DEF 14A of Clean Harbors Inc, Apr 10, 2026

DEF 14A of Clean Harbors Inc

Filed Apr 10, 2026 · FY20250000822818-26-000013

Open on EDGAR

  1. ELECTION OF DIRECTORS

    ELECTION OF DIRECTORS

  2. (Proposal 1 on Proxy Form)

    (Proposal 1 on Proxy Form) The Board is the ultimate decision-making body of the Company except with respect to those matters reserved to the shareholders by law or pursuant to the Company’s Restated Articles of Organization or its By-Laws. The Board is responsible for selection of the Chief Executive Officer(s) and for advising the Chief Executive Officer(s) with respect to the selection of a management team, providing oversight responsibility and direction to management, and evaluating the performance of management on behalf of the shareholders. As more fully described above under “Director Independence”, the Board has determined that, except for Alan S. McKim, the Company’s Executive Chairman and Chief Technology Officer, and Michael L. Battles and Eric W. Gerstenberg, the Company's Co-Chief Executive Officers, all of the current members of the Board are “independent directors” as defined by the NYSE rules. In 2025, the Board held six meetings. Overall attendance at Board and committee meetings was over 95% and attendance was at least 75% for each director. All current members of the Board who were then serving as directors also attended the 2025 annual meeting of shareholders in person. While the Company does not have a formal policy, it has been longstanding practice that all directors attend the annual meeting of shareholders unless there are unavoidable schedule conflicts or unforeseen circumstances. The Board is currently composed of 13 directors classified into three classes. There are currently four Class I directors, four Class II directors, and five Class III directors. One class of directors is elected each year for a term of three years. The term of the current Class I directors, Edward G. Galante, Alison A. Quirk, Shelley Stewart, Jr., and John R. Welch, will expire at the 2026 annual meeting and the Board has nominated all of the four current Class I directors to stand for re-election as Class I directors at the 2026 annual meeting, each to serve for a term of three years until the 2029 annual meeting of shareholders and until their respective successors are duly elected and qualified or their earlier resignation or removal.

  3. Board Matrix

    Board Matrix The following matrix provides information regarding the 13 current members of the Board, including certain types of knowledge, skills, experiences, and attributes possessed by one or more of the directors that the Board believes are relevant to our business and corporate structure. The matrix does not encompass all of the knowledge, skills, experiences, or attributes of our directors, and the fact that a particular knowledge, skill, experience, or attribute is not listed does not mean that a director does not possess it. In addition, the absence of a particular knowledge, skill, experience, or attribute with respect to any of the directors does not mean the director in question is unable to contribute to the decision-making process in that area. The type and degree of knowledge, skill, and experience listed below may vary among the members of the Board. As more fully described above under “Board of Directors and Corporate Governance - Board Committees,” the Board's Corporate Governance and Sustainability Committee, which is composed solely of independent directors, is responsible for selecting nominees to recommend to the full Board for election as directors. In that capacity, the Corporate Governance and Sustainability Committee and the full Board determine on an annual basis the appropriate characteristics, skills, and experience for the Board as a whole and for its individual members. The following tables summarize the composition of the Company’s Board: In evaluating the suitability of individual Board members, the Corporate Governance and Sustainability Committee and the full Board take into account many factors in addition to high personal and professional ethics, integrity, and values, including particular industry or geographic experience; understanding of the business of the Company; particular disciplines such as finance, sales, management, engineering and technology; cybersecurity risk experience; and personal, educational, and professional background. The Corporate Governance and Sustainability Committee and the full Board evaluate each individual in the context of the Board as a whole, with the objective of recommending nominees for election as director who can best enhance the success of the Company and represent shareholder interests through the exercise of sound judgment in the context of the diversity of experience of the various directors. In choosing individuals to recommend for nomination to the Board, the Corporate Governance and Sustainability Committee seeks individuals with particular skills complementary and additive to those currently held by the Board or knowledge and experience that the Board is likely to need in the future. The Board also has a policy under which each director who wishes to stand for re-election will be evaluated by the other members of the Board based on such director’s contributions to the activities of the Board prior to being nominated by the Board for re-election.

  4. Board Nomination Process

    Board Nomination Process In the past, all nominees for the Board have been submitted to the Corporate Governance and Sustainability Committee by members of the Board. However, the Corporate Governance and Sustainability Committee will also consider shareholder recommendations for Board candidates. The Corporate Governance and Sustainability Committee has not adopted a formal policy with regard to the consideration of director candidates recommended by shareholders; however for any candidate properly proposed by a shareholder as described in the following paragraph, the Corporate Governance and Sustainability Committee will use the same evaluation criteria as are described above in assessing such candidate for purposes of potential recommendation to the Board. For the 2027 annual meeting of shareholders, any shareholder wishing to propose a candidate for consideration by the Corporate Governance and Sustainability Committee should deliver a notice addressed to the Chair, Corporate Governance and Sustainability Committee, in the manner described above under “Board of Directors Overview - Communications to the Independent Directors.” Unless the shareholder desires to formally nominate a director for election at the 2027 annual meeting, in which event the shareholder would need to comply with the procedures described below in this proxy statement under “Shareholder Proposals,” such notice should be delivered by not later than the close of business on March 22, 2027 (60 calendar days prior to the anniversary of the 2026 annual meeting). Such notice should include the name of the proposed candidate for election as a director and a brief biography, a document indicating the candidate's willingness to serve, evidence of the nominating person's ownership of Company stock, and certain other information about the candidate and the shareholder that is described in Article II, Section 2(b) of the Company’s By-Laws. A copy of the Company’s By-Laws as now in effect is available at the SEC's website at http://www.sec.gov as Exhibit 3.4D to the Company’s Current Report on Form 8-K filed on March 16, 2022, and may also be obtained without cost by writing to Clean Harbors, Inc., 42 Longwater Drive, Norwell, MA 02061, Attention: Executive Office.

  5. Current Directors and Nominees

    Current Directors and Nominees The following paragraphs provide information as of the date of this proxy statement about each of the Company’s 13 current directors. The directors include the four current Class I directors standing for re-election at the annual meeting, namely Edward G. Galante, Alison A. Quirk, Shelley Stewart, Jr., and John R. Welch, and the nine current directors who are not standing for re-election at the annual meeting but will continue to serve in accordance with their current terms as Class II directors until 2027 or Class III directors until 2028. The information includes age, positions, principal occupation, and business experience of each director for at least the past five years, the names of other publicly-held companies of which he or she currently serves as a director or has served as a director during the past five years, and any material legal proceedings during the past ten years that might be relevant to service as a director. The information also includes the Board committees on which each of the directors now serves. In addition to the information presented below regarding each director's specific experience, qualifications, attributes, and skills that led the Corporate Governance and Sustainability Committee and full Board to conclude that he or she should serve as a director, the Corporate Governance and Sustainability Committee and Board also believe that all of the directors have high personal and professional ethics, integrity, and values, and each of them has demonstrated business acumen, sound judgment, and a commitment of service to the Company. Current Class I Directors Standing for Re-election at the Meeting:

  6. Current Directors and Nominees

    | Edward G. Galante Age: 75 Director Class: I Director Since: 2010 Committees: Lead Director | Mr. Galante retired in 2006 after more than 30 years with Exxon Mobil Corporation. Prior to his retirement, he most recently served as a Senior Vice President and member of the Management Committee of Exxon Mobil Corporation. His principal responsibilities included the worldwide Downstream business: Refining & Supply, Fuels Marketing, Lubricants and Specialties Marketing and Research, and Engineering. He was also responsible for Exxon Mobil's corporate Public Affairs and Safety, Health and Environmental activities. Mr. Galante received his Bachelor of Science degree in civil engineering from Northeastern University, and he now serves as a Vice Chairman of Northeastern's Board of Trustees. He is currently a director of Celanese Corporation (NYSE: CE), where he chairs the board of directors. Within the past five years, Mr. Galante was also a director of Linde plc (NYSE:LIN), where he chaired the compensation and executive development committee and sat on the audit committee, and Marathon Petroleum Corporation, (NYSE: MPC) where he chaired the compensation and organizational development committee and served on the sustainability committee. Mr. Galante is also a director of the United Way Foundation of Metropolitan Dallas and of Artis-Naples. Skills and Qualifications: In addition to his extensive experience with Exxon Mobil in the oil and gas industry, Mr. Galante's experience as a director and board committee member of three other major public companies give him valuable insight into corporate governance, public affairs, environmental, compensation, and audit matters. |

  7. Current Directors and Nominees

    | Alison A. Quirk Age: 64 Director Class: I Director Since: 2022 Committees: Compensation and Human Capital (Chair) Corporate Governance and Sustainability | Ms. Quirk is the former Executive Vice President, Chief Human Resources and Citizenship Officer at State Street Corporation. Ms. Quirk retired from State Street in 2017, where she worked for 15 years, the last seven as a member of the company’s senior-most strategy and policy making group. As Chief Human Resources and Citizenship Officer, she was responsible for all aspects of human resources and corporate citizenship, leading a global team of more than 500 people. Prior to State Street, Ms. Quirk spent two decades in human resources and business planning roles at FleetBoston Financial, Liberty Financial Companies and Boston Financial Data Services, Inc. Ms. Quirk is an independent non-executive director of Janus Henderson Group plc (NYSE/ASX:JHG), where she is the chair of the human capital and compensation committee. She is also a member of the board of Embrace Boston, an equity and social justice organization focused on arts/culture and research/policy, where she is also a member of the executive committee and the program committee and chair of the compensation committee. She previously served as a member of the compliance committee of Wynn Resorts, Limited (NASDAQ:WYNN) and on the Legg Mason board of directors as a member of the finance committee and the nominating and governance committee, as well as chairperson of the compensation committee. She also served on a special committee of the board that oversaw the sale of Legg Mason. She holds a bachelor’s degree in Communications from the University of New Hampshire. Skills and Qualifications: Ms. Quirk brings valuable board-level experience advising on corporate strategy, mergers and acquisitions, and company growth objectives. Her background as a senior human resources executive fully aligns with the Company’s initiatives around recruiting, retention, and employee engagement. | | Shelley Stewart, Jr. Age: 72 Director Class: I Director Since: 2022 Committees: Audit Environmental, Health, and Safety | Mr. Stewart leads the consulting firm Bottom Line Advisory LLC as Managing Partner. Mr. Stewart retired in 2018 after six years as Chief Procurement Officer at DuPont where he led procurement, global sourcing, and logistics, as well as real estate and facility services. Prior to joining DuPont in 2012, he spent nearly a decade at Tyco International, where he was Senior Vice President of Operational Excellence and Chief Procurement Officer and oversaw multiple Lean Six Sigma initiatives. Previously, he held senior executive supply chain positions at Raytheon and Invensys PLC. He also spent 19 years at United Technologies Corporation, where he held numerous positions around global sourcing. Mr. Stewart currently serves on the boards of Otis Worldwide Corporation (NYSE:OTIS) and Kontoor Brands Inc. (NYSE:KTB), where he sits on their respective nominating and governance and audit committees. He also serves on the Board of Trustees of Howard University and the Board of Governors for the University of New Haven. He previously spent several years serving on the board of directors for the Institute for Supply Management. He holds a bachelor’s degree and master’s degree in criminal justice from Northeastern University and received his MBA from the University of New Haven. Skills and Qualifications: Mr. Stewart brings significant expertise in areas such as logistics, supply chain management, and operational improvement. His strategic insights, combined with his chemical industry background, are a significant asset to Clean Harbors as the Company continues to execute its growth strategy. |

  8. Current Directors and Nominees

    | John R. Welch Age: 69 Director Class: I Director Since: 2014 Committees: Compensation and Human Capital Environmental, Health, and Safety Ad Hoc Cyber (Chair) | Mr. Welch retired as a Senior Partner from McKinsey & Company, an international consulting firm, in 2015 after 30 years, and is now a Senior Partner Emeritus. While at McKinsey, he served clients across a variety of industries, served as the Managing Partner of McKinsey’s New England Practice from 2007 to 2012, and led McKinsey's Strategy Practice from 2001 to 2005. Prior to joining McKinsey, Mr. Welch was a project engineer with Hooker Chemical and with Caltex Petroleum, and worked in the Municipal Lending Group at Bank of America. Mr. Welch is currently an Executive Partner at Bridge Growth Partners, LLC, a private equity firm, and he previously served on the board of Finalsite, a private software company. He holds an MBA from the University of Chicago, and BS and MS degrees in chemical engineering from Cornell University. Skills and Qualifications: Mr. Welch brings to the Board his considerable experience in business consulting, operations, and finance. |

  9. Current Directors and Nominees

    Continuing Directors Not Standing for Re-election at the Meeting:

  10. Current Directors and Nominees

    | Michael L. Battles Age: 57 Director Class: III Director Since: 2024 Committees: None | Michael L. Battles was appointed as the Company’s Co-Chief Executive Officer and Co-President effective March 31, 2023, and has been a member of the Board since August 2024. He joined the Company in September 2013 as Senior Vice President, Corporate Controller and Chief Accounting Officer and was appointed as Executive Vice President and the Company’s Chief Financial Officer in January 2016. Mr. Battles previously served in a variety of senior financial positions at PerkinElmer Inc., a global leader in human and environmental health. His roles included financial leadership of the Human Health business, Chief Accounting Officer, and acting Chief Financial Officer. Prior to PerkinElmer, Mr. Battles worked for Deloitte & Touche LLP in various positions of increasing management responsibility within the firm's audit function, including an assignment in accounting research at Deloitte & Touche LLP’s national office. Mr. Battles is a member of the board of directors of Casella Waste Systems, Inc. (NASDAQ: CWST), a regional solid waste, recycling and resource management service company, and serves on its audit committee and nominating and ESG committee. He holds a BS in Business Administration with a concentration in Accounting from the University of Vermont and is a certified public accountant. He also has a Certificate in Cybersecurity Oversight issued by the National Association of Corporate Directors and Carnegie Mellon University. Skills and Qualifications: Mr. Battles has accumulated significant expertise in finance, accounting, risk management, cyber security, and capital management through his extensive experience both at the Company and in previous roles. | | Eric W. Gerstenberg Age: 57 Director Class: III Director Since: 2024 Committees: None | Eric W. Gerstenberg was appointed as the Company’s Co-Chief Executive Officer and Co-President effective March 31, 2023 and has been a member of the Board since August 2024. Prior to his current role, Mr. Gerstenberg served as the Company’s Chief Operating Officer since January 2015. Mr. Gerstenberg started with the Company in 1989 in Field Operations. From 1989 to 1997, he held a variety of management positions, including General Manager of multiple facilities. From 1997 to 1999, Mr. Gerstenberg was the Vice President of Operations for Pollution Control Industries, a privately-owned environmental services company. Mr. Gerstenberg rejoined the Company in June 1999 as Executive Vice President - Environmental Services and became President, Environmental Services in June 2014. Mr. Gerstenberg holds a BS in Engineering from Syracuse University. In 2017, he attended and received certification at the Harvard Business School Advanced Management Program (AMP193). Skills and Qualifications: Mr. Gerstenberg has accumulated extensive experience in operations, safety, strategy, and business development through his various roles at the Company and his engineering background. |

  11. Current Directors and Nominees

    | Alan S. McKim Age: 71 Director Class: II Director Since: 1980 Committees: None | Mr. McKim founded the Company in 1980 and has served as the Chairman of the Board of Directors since its founding and as the Chief Technology Officer since March 31, 2023. Prior to that, Mr. McKim had served as the Company’s Chief Executive Officer and President since the Company’s founding in 1980. Mr. McKim holds an MBA from Northeastern University's D'Amore - McKim School of Business and an honorary doctorate from the Massachusetts Maritime Academy. He serves on Northeastern University's Board of Trustees and South Shore Health's Board of Directors. Skills and Qualifications: Mr. McKim is recognized as an industry leader, with more than four decades of experience in the environmental services business. He is also the largest individual shareholder of the Company, and his interests are therefore significantly aligned with those of the other shareholders. | | Karyn Polito Age: 59 Director Class: II Director Since: 2023 Committees: Audit Corporate Governance and Sustainability Environmental, Health, and Safety | Ms. Polito is the Principal of Polito Development Corporation, a commercial and industrial real estate development firm. She served as 72nd Lieutenant Governor of Massachusetts from 2015 to 2023. Prior to her election as Lieutenant Governor, Ms. Polito was a member of the Massachusetts House of Representatives and a Partner at Milton, Laurence & Dixon, LLP. She is an independent director for Beacon Financial Corporation (NYSE:BBT), following the merger of Berkshire Hills Bancorp, Inc. (NYSE:BHLB), a company for which Ms. Polito had previously been a board member, and Brookline Bancorp, Inc. Ms. Polito serves on the compensation committee and corporate governance and nominating committee of Beacon Financial Corporation. She also serves as an independent director for The Andover Companies, a private mutual insurance group. She holds a Bachelor of Science from Boston College and a Juris Doctor from New England Law School. Skills and Qualifications: Ms. Polito brings to the Board a wealth of experience across the public and private sectors, including environmental issues, government, regulations, and public affairs, as well as serving on the board of another public company. | | John T. Preston Age: 76 Director Class: II Director Since: 1995 Committees: Corporate Governance and Sustainability (Chair) Ad Hoc Cyber | Mr. Preston is the Managing Partner of TEM Capital, a private equity investment company, and is currently a director of numerous private companies. From 1992 through 1995, he served as Director of Technology Development at the Massachusetts Institute of Technology (“MIT”). Prior to that he was the Director of the MIT Technology Licensing Office where he was responsible for the commercialization of intellectual property developed at MIT. Some of Mr. Preston's prior appointments include director or advisory positions for the Governor of Massachusetts, the U.S. Department of Defense, the National Aeronautics and Space Administration, and the National Technology Board of Singapore. He holds a BS in Physics from the University of Wisconsin and an MBA from Northwestern University. Skills and Qualifications: Mr. Preston brings to the Board his considerable experience in technology development, corporate growth and corporate governance. Mr. Preston also has a Certificate in Cybersecurity Oversight issued by the National Association of Corporate Directors and Carnegie Mellon University. |

  12. Current Directors and Nominees

    | Marcy L. Reed Age: 63 Director Class: II Director Since: 2021 Committees: Audit (Chair) Environmental, Health, and Safety Ad Hoc Cyber | Ms. Reed retired in 2021 after more than 30 years with National Grid, an investor-owned public utility providing New York, Rhode Island and Massachusetts with natural gas and electricity for homes and businesses. Prior to her retirement, she had served for a decade as President of National Grid Massachusetts and Executive Vice President U.S. Energy Policy and Social Impact. She has been a certified public accountant since 1988. A frequent speaker on topics of leadership, energy policy, innovation, and the evolving energy paradigm, she has been recognized with numerous leadership and philanthropic awards, including being named three times as one of Boston’s Top 100 Leaders. In February 2022, Ms. Reed joined the board of Edison International (NYSE:EIX), the parent company of Southern California Edison. She serves as an independent director for Blue Cross Blue Shield of Massachusetts and is on the board of Northeastern University where she serves as the chair of the audit committee. She also is a board member of Qualus, a private equity-backed electric power engineering company. Ms. Reed previously served as board chair of The Partnership, Inc., an organization working to build racially diverse leadership pipelines. She earned an AB in Economics from Dartmouth College and an MS in Accounting from Northeastern University and holds Executive Education Certificates from the Wharton School of the University of Pennsylvania and INSEAD. Skills and Qualifications Ms. Reed brings to the Board her considerable experience in the energy industry, accounting, and regulatory matters. Ms. Reed qualifies as an “audit committee financial expert” under Regulation S-K under the Exchange Act. | | Andrea Robertson Age: 68 Director Class: III Director Since: 2004 Committees: Audit Corporate Governance and Sustainability | Ms. Robertson was the Group Executive, Corporate Treasurer of MasterCard Worldwide from 2003 to June 2010. Ms. Robertson held financial management positions with RR Donnelley & Sons Company from 1996 to 2003, and with International Business Machines Corporation ("IBM") from 1984 to 1996. From 1979 to 1982, she was an auditor with Coopers & Lybrand. She holds a BS in Accounting from Merrimack College and an MBA in Finance/Management Information Systems from the University of Chicago. She is a certified public accountant. She is an Impact Partner for Prevent Child Abuse America, where she had previously sat on the board. Skills and Qualifications: Ms. Robertson brings to the Board her considerable knowledge and experience in finance and risk management from her training as an accountant and her work in financial management positions. She qualifies as an “audit committee financial expert” under Regulation S-K of the Exchange Act. |

  13. Current Directors and Nominees

    | Lauren C. States Age: 69 Director Class: III Director Since: 2016 Committees: Compensation and Human Capital Environmental, Health, and Safety (Chair) Ad Hoc Cyber | Ms. States retired in 2014 after more than 36 years with IBM. Prior to her retirement, she served as Vice President, Strategy and Transformation for IBM’s Software Group and as a member of the Growth and Transformation senior leadership team. Her principal responsibilities included leading the global sales force strategy and go-to-market for IBM’s multi-billion dollar software business. From 2008 to 2013, she was a leader in IBM’s transformation to cloud computing, working with clients to provide insights to IBM’s strategy and serving as Chief Technology Officer in the corporate strategy function. Over her career, she has served in a broad variety of roles including technology, transformation, sales, and talent development. Ms. States received her BS in Economics from The Wharton School of the University of Pennsylvania. In 2015, she completed a Fellowship with Harvard University’s Advanced Leadership Initiative. She is a director of Webster Financial Corporation (NYSE:WBS) and Quid, a privately held company and, through early 2023, served on the board of directors of Diebold Nixdorf Inc. (NYSE:DBD). Ms. States serves as Trustee for International House, New York and Mercy High School in Middletown, Connecticut. Ms. States also serves on the board of Code Nation and previously served on the board of the New England Science and Sailing Foundation through April 2023. Skills and Qualifications: Ms. States brings to the Board her considerable experience in sales, technology, and strategy at a major technology company, as well as from serving as a director of other public companies. Ms. States also has a Certificate in Cybersecurity Oversight issued by the National Association of Corporate Directors and Carnegie Mellon University. | | Robert J. Willett Age: 58 Director Class: III Director Since: 2019 Committees: Compensation and Human Capital Corporate Governance and Sustainability | Mr. Willett was Chief Executive Officer of Cognex Corporation (NASDAQ: CGNX), a machine vision company, from 2011 through June 2025, where he oversaw all aspects of strategy and operations. He joined Cognex in 2008 as Executive Vice President and President of the Modular Vision Systems Division. He was promoted to Chief Operating Officer in 2010 and to Chief Executive Officer in 2011. Mr. Willett served on the Cognex board of directors from 2011 to 2026. Before joining Cognex, he served as Group Vice President of Business Development and Innovation for the Product Identification business group at Danaher Corporation (NYSE:DHR), a diversified manufacturer of industrial controls and technologies. Prior to that, he served as President of Danaher subsidiary Videojet Technologies. From 1998 to 2003, Mr. Willett served as Chief Executive Officer of Willett International Ltd., a $125 million private coding company with 30 wholly-owned sales companies around the world, which he sold to Danaher in 2003. In February 2026, Mr. Willett was appointed to the board of Formlabs, a privately held company, and in March 2026, he retired from the board of Cognex, which he joined in 2011. Mr. Willett holds a BA from Brown University and an MBA from Yale University. Skills and Qualifications: As the former chief executive officer of a public machine vision company, Mr. Willett has a deep industrial and technology background and expertise in leadership development. He serves as a valuable resource as the Company continues to execute its growth strategy. |

  14. Current Directors and Nominees

    Election of each of the four Class I directors standing for re-election will require the affirmative vote of the holders of a majority of the votes cast on the election of such nominee at the annual meeting. Abstentions and broker non-votes will not have any impact on the outcome of this proposal, and votes withheld from any nominee will have the effect of “against” votes with respect to such nominee. Any incumbent director who fails to receive the required number of votes for his or her re-election is required by our By-Laws to submit his or her resignation to the Board. Our Corporate Governance and Sustainability Committee will then make a recommendation to the Board as to whether such resignation should be accepted or rejected, or whether other action should be taken. The Board is required to act on the tendered resignation and publicly disclose its decision within 90 days of the certification of the shareholder vote for the annual meeting. Any director who tenders his or her resignation may not participate in such process regarding his or her resignation. If such director's resignation is not accepted by the Board, such director will continue to serve until the next annual meeting of shareholders and until his or her successor is duly elected and qualified, or his or her resignation or removal. Unless otherwise specified therein, shares represented by the accompanying form of proxy will be voted to re-elect Edward G. Galante, Alison A. Quirk, Shelley Stewart, Jr., and John R. Welch as Class I directors of the Company for a three-year term until the 2029 annual meeting of shareholders and until their respective successors are duly elected and qualified or until their earlier death, resignation or removal. In the event that any of the nominees is unable to stand for election (which is not now contemplated), the holders of the accompanying form of proxy will vote for the election of such other person as the remaining members of the Board may recommend. The Board recommends shareholders vote “FOR” the election of Edward G. Galante, Alison A. Quirk, Shelley Stewart, Jr., and John R. Welch as Class I directors.

  15. DIRECTOR COMPENSATION

    DIRECTOR COMPENSATION During 2025, the Company paid an annual cash retainer fee of $90,000 to each non-employee director, plus $65,000 for serving as the Lead Director, $25,000 for serving as the Chair of the Audit Committee, $20,000 for serving as the Chair of the Compensation and Human Capital Committee, and $15,000 for serving as the Chair of the Corporate Governance and Sustainability Committee, the Environmental, Health, and Safety Committee, or the Ad Hoc Cyber Committee. Directors are not paid for attendance at meetings, but non-employee directors are reimbursed for expenses they incur in connection with service on the Board and its committees. The Company does not provide any pension, deferred compensation, or charitable award programs to any of its non-employee directors. Any director who is an employee of the Company does not receive any additional compensation for serving as a director. In addition to the cash compensation described above, immediately following the 2025 annual meeting of shareholders, each non-employee director either elected at the 2025 annual meeting or then continuing to serve as a director received 789 restricted shares of the Company’s common stock under the Company’s 2020 Stock Incentive Plan, having a grant date fair value of approximately $180,000. The share quantity awarded was calculated using the closing share price on May 21, 2025. All of the restricted shares granted to the non-employee directors immediately following the 2025 annual meeting are for services provided as non-employee directors through the 2026 annual meeting of shareholders and will vest at that time provided such directors continue to serve as directors through such date. The Corporate Governance and Sustainability Committee reviews non-employee director compensation on a periodic basis. The Corporate Governance and Sustainability Committee then recommends any changes in the compensation for non-employee directors to the full Board for its consideration and approval. Many factors are considered in making a recommendation to the Board, including market trends, responsibilities of our non-employee directors, the anticipated time commitment and amount of work, the responsibilities of various committees of our Board, and the ability to attract and retain non-employee directors with desired attributes to serve on the Board. The C&HC Committee also engaged Meridian Compensation Partners, to provide input to the Corporate Governance and Sustainability Committee regarding compensation for non-employee directors. The following table describes the compensation paid by the Company to each of the non-employee directors during 2025:

  16. DIRECTOR COMPENSATION

    | Name | Fees Earned or Paid in Cash ($) | Stock Awards (1)(2) ($) | Total ($) | | Edward G. Galante | 155,000 | 179,987 | 334,987 | | Karyn Polito | 90,000 | 179,987 | 269,987 | | John T. Preston | 105,000 | 179,987 | 284,987 | | Alison A. Quirk | 110,000 | 179,987 | 289,987 | | Marcy L. Reed | 115,000 | 179,987 | 294,987 | | Andrea Robertson | 90,000 | 179,987 | 269,987 | | Lauren C. States | 105,000 | 179,987 | 284,987 | | Shelley Stewart, Jr. | 90,000 | 179,987 | 269,987 | | John R. Welch | 105,000 | 179,987 | 284,987 | | Robert J. Willett | 90,000 | 179,987 | 269,987 |

  17. DIRECTOR COMPENSATION

    ____________________________ (1) The grant date fair value of stock awards is calculated in accordance with Financial Accounting Standards Board (“FASB”) Accounting Standards Codification (“ASC”) Topic 718. For restricted stock awards subject to time-based vesting, the grant date fair value is based on the value of the awards on the grant date using the closing price of the Company’s common stock on such date. As of December 31, 2025, each non-employee director, held 789 unvested restricted shares. (2) None of the non-employee directors was granted any stock options during 2025, nor do they currently hold any stock options.

  18. Executive Summary

    | Name | Base Salary (1) ($) | Target Annual Cash Incentives (2) ($) | Target Annual Long-Term Incentives (3) ($) | | Michael L. Battles | 1,000,000 | 1,500,000 | 3,810,000 | | Eric W. Gerstenberg | 1,000,000 | 1,500,000 | 3,810,000 | | Eric J. Dugas | 565,000 | 734,500 | 904,000 | | Brian P. Weber | 630,000 | 819,000 | 1,008,000 | | Jeroen Diderich | 625,000 | 812,500 | 1,000,000 | | Alan S. McKim | 900,000 | 1,350,000 | — |

  19. Executive Summary

    (1) Reflects base salary in effect for each NEO as of December 31, 2025 and may differ from the amounts reported in the Summary Compensation Table which reflect the actual salary earned during 2025. (2) Reflects 2025 target incentive amounts, calculated as a percentage of the Base Salary amounts in the table above. These values differ from the amounts reported in the Summary Compensation Table, which reflect the actual incentives earned for 2025 and were paid in the first quarter of 2026. (3) Reflects target value of annual performance-based and time-based restricted shares. Amounts above may differ from the amounts reported in the Stock Awards column of the Summary Compensation Table, which presents the grant date fair value, as computed in accordance with FASB ASC 718. The C&HC Committee generally designs the Company’s compensation programs so that at least 70% of the NEOs’ total target compensation is at risk. In designing the total compensation package, the C&HC Committee took into consideration that Mr. McKim is the Company’s founder and largest individual shareholder and therefore his interests are significantly aligned with those of the other shareholders. As such, Mr. McKim generally does not receive equity awards as part of his compensation. The total potential compensation for the remaining NEOs for 2025 was, on average, more than 70% at risk. The portion of total compensation which is at risk consists of: i.annual cash incentives at target, the value of which is determined and earned only if the predetermined Company or individual goals approved by the C&HC Committee are achieved, ii.performance-based restricted shares at target that are earned and become eligible to vest only if certain predetermined objective Company goals approved by the C&HC Committee are achieved, and iii.time-based restricted shares with vesting dependent upon continued employment of the recipient over the vesting period and whose ultimate value to the employee is dependent upon the performance of the Company’s common stock price. The portion of total compensation that is not at risk consists of base salaries that are generally competitive with those offered by other companies with which the Company competes for executive talent. The charts below depict the target compensation mix for both the Co-CEOs and the average of the other NEOs (excluding Mr. McKim) using total compensation as described above: The C&HC Committee established the goals for performance-based cash bonuses and performance-based restricted share awards, which are discussed further in Compensation Philosophy and Objectives, at levels it believes are sufficiently difficult to achieve in order to provide a significant incentive for participants to drive the Company’s performance. The C&HC Committee has also obtained advice concerning the structuring of the Company’s executive compensation plans from Meridian Compensation Partners, LLC, an independent compensation consulting firm specializing in the development and implementation of executive compensation systems. Pursuant to its commitment to pay-for-performance and good corporate governance, the C&HC Committee has implemented the following compensation related practices as in effect for 2025: This CD&A addresses the Company and individual performance goals for the NEOs. Those goals are disclosed in the limited context of the Company’s executive compensation programs, and investors should not interpret them as statements of the Company’s expectations or as any form of guidance.

  20. Use of Compensation Consultants

    Use of Compensation Consultants Under its charter, the C&HC Committee has authority to select and retain its own executive compensation consultants, legal counsel, and other advisors to assist the C&HC Committee in its determinations. The C&HC Committee has engaged an outside compensation consultant to assist the C&HC Committee in applying its compensation philosophy for our executive officers, analyzing current compensation conditions in the marketplace generally and among our peers specifically, and assessing the competitiveness and appropriateness of compensation levels for our executive officers. The C&HC Committee retained Meridian Compensation Partners, LLC (“Meridian”) as its independent compensation consultant in early 2025, a role which Meridian began in early 2022. Representatives of Meridian regularly attend C&HC Committee meetings, both with and without members of management present, and interact with members of our human resources department with respect to its assessment of the compensation for our executive officers. The C&HC Committee has also engaged Meridian to provide input to the Corporate Governance and Sustainability Committee regarding compensation for non-employee directors. The Corporate Governance and Sustainability Committee then recommends any changes in the compensation and benefits for non-employee directors to the full Board for its consideration and approval. After considering the independence assessment factors provided under the NYSE listing rules, the C&HC Committee determined that Meridian is independent and that the work Meridian performed during 2025 did not raise any conflicts of interest. The C&HC Committee considered the services provided by Meridian, as well as informational responses provided by Meridian to the C&HC Committee on topics relevant to assessing Meridian's relationship with Clean Harbors and our management team, and determined that such services do not compromise Meridian's independence as the C&HC Committee's independent compensation consultant.

  21. Use of Market Data and Competitive Compensation Positioning

    Use of Market Data and Competitive Compensation Positioning Our executive compensation program takes into account the compensation practices of companies with which we compete or could compete for executive talent. For compensation decisions made related to 2025, the relevant peer group as selected by the C&HC Committee, in consultation with Meridian, included the following companies, after consideration of a number of financial, industry, and qualitative factors, including overall business model comparability, operating size, valuation, margins, growth, and shareholder returns:

  22. Use of Market Data and Competitive Compensation Positioning

    | ABM Industries Incorporated | EMCOR, Inc. | Republic Services, Inc. | | Advanced Drainage, Inc. | Enviri Corporation | Rollins, Inc | | APi Group Corporation | GFL Environmental Inc. | Stericycle | | Chemed Corporation | Huntsman Corporation | Tetra Tech Inc. | | The Chemours Company | Iron Mountain, Inc. | Waste Connections, Inc. | | Darling Ingredients Inc. | KBR, Inc. | Waste Management, Inc. | | Ecolab Inc. | | |

  23. Use of Market Data and Competitive Compensation Positioning

    In August 2024, the C&HC Committee elected to use the peer group listed above for the 2025 compensation benchmarking. At the time the peer group was selected, we estimated that the Company was positioned at approximately the 35th percentile of the group in revenue and 55th in market capitalization. While the C&HC Committee considers comparative data from this peer group to be a useful reference in evaluating and adjusting executive compensation, it does not target overall compensation—or any specific element—to fall within a particular percentile or range relative to peers. Instead, the Committee reviews peer group information alongside relevant industry compensation surveys to ensure that our executive compensation program remains competitive. In setting target compensation levels, the C&HC Committee applies judgment and discretion, taking into account not only market data, but also each executive’s experience, scope of responsibilities, critical skills, and expertise.

  24. Performance-Based Cash Bonuses

    Performance-Based Cash Bonuses The C&HC Committee is authorized to grant cash bonuses to the NEOs under the MIP. Cash bonuses for NEOs under the MIP are earned based on the achievement of performance goals established by the C&HC Committee in two components, a Company performance component based on the achievement of Company performance goals (“Annual MIP Bonus”), and for all of the NEOs other than the Co-CEOs and Mr. McKim, an individual performance component based on the achievement of individualized performance objectives (known as the Supplemental Executive Incentive Plan or “SEIP”). Each NEO has an annual incentive target that is expressed as a percentage of the NEO’s base salary, as shown for 2025 in the table below:

  25. Performance-Based Cash Bonuses

    | Name | Annual MIP % | SEIP % | Combined % | | Michael L. Battles | 150% | — | 150% | | Eric W. Gerstenberg | 150% | — | 150% | | Eric J. Dugas | 50% | 80% | 130% | | Brian P. Weber | 50% | 80% | 130% | | Jeroen Diderich | 50% | 80% | 130% | | Alan S. McKim | 150% | — | 150% |

  26. Performance-Based Cash Bonuses

    Annual MIP Bonus For the Annual MIP Bonus, the C&HC Committee establishes performance metrics during the first quarter of each fiscal year and determines the achievement levels for those metrics during the first quarter of the following fiscal year. On January 27, 2025, the C&HC Committee identified revenue, Adjusted EBITDA, Adjusted FCF, and TRIR as the performance metrics for the 2025 Annual MIP bonus, as defined in the Definitions for 2025 Incentive Compensation section of Appendix B. The performance metrics were established based on the 2025 budget, which was approved by the Board in December 2024, and therefore are linked with the strategic initiatives for the year. Additionally, these key financial targets measure strategic annual growth, overall operating performance, and cash flow generation, which align with measures of the Company’s performance and shareholder value. Finally, safety is a core value throughout Clean Harbors. Employees at all levels of our organization share this belief and are committed to keeping our teams, customers, and communities safe, and therefore the C&HC Committee has selected TRIR to reflect our continued commitment to safety. To reflect the market driven variability inherent in the Safety‑Kleen Sustainability Solutions (“SKSS”) segment, the revenue metric applies only to Environmental Services and Corporate (“ES & Corp”) operations. In addition, the C&HC Committee established separate Adjusted EBITDA metrics—one for ES & Corp operations, and another for the SKSS segment—with proportional weightings assigned to each. The following table summarizes the C&HC Committee’s determination of the weighting, threshold, target and maximum levels for each of the performance metrics for the 2025 Annual MIP Bonus (in thousands, except percentages and TRIR):

  27. Performance-Based Cash Bonuses

    | Metric | Weighting | Threshold | Target | Maximum | | Revenue - ES & Corp ($) | 20% | 5,016 | 5,232 | 5,544 | | Adjusted EBITDA - ES & Corp ($) | 35% | 984 | 1,036 | 1,088 | | Adjusted EBITDA - SKSS ($) | 5% | 131 | 154 | 177 | | Adjusted Free Cash Flow ($) | 20% | 395 | 440 | 485 | | TRIR | 20% | 0.70 | 0.69-0.60 | 0.60 |

  28. Performance-Based Cash Bonuses

    The achievement of the metrics is determined in the first quarter of the following year. The Annual MIP payout is calculated as follows: Annual MIP Bonus = Base Salary × Annual MIP % × Performance Factor. The performance factor is based on the achievement of the metrics in the table above. For the Co-CEOs and Mr. McKim, the performance factors are: 50% at threshold, 100% at target, and 150% at maximum. For the remaining NEOs, the performance factors are: 40% at threshold, 100% at target, and 140% at maximum. For amounts in between the threshold and target or target and maximum, the performance factor is based on a predetermined linear scale for all the metrics other than TRIR, which has a tiered payout of the performance factor noted in the previous paragraph with no interpolation in between the Threshold, Target and Maximum. As described in the Role of the C&HC Committee above, over the course of the year, the C&HC Committee determines whether any adjustments are appropriate in consideration of extraordinary events such as a major acquisition or divestiture, or a change in GAAP or applicable law. For 2025, the results have been adjusted for the enactment of One Big Beautiful Bill in July 2025, which impacted Adjusted FCF, as well as certain acquisition, divestiture, severance, and integration related costs, all of which were not contemplated in the 2025 Annual MIP targets. Additionally, the results were adjusted for a strategic capital project that was included in the target but was not included in the externally disclosed Adjusted FCF for 2025. Please see Reconciliation of Actual Results for Annual Incentive Performance Measures in Appendix B for more information of such adjustments. The table below summarizes the achievement for the Annual MIP bonus for 2025, which the C&HC Committee approved on March 6, 2026, and the actual earned bonuses subsequently paid out to the NEOs (amounts in thousands, except percentages and TRIR):

  29. Performance-Based Cash Bonuses

    | Metric | Weighting | 2025 Results | Co-CEO/ McKim Performance Factor | NEO Performance Factor | | Revenue - ES & Corp ($) | 20% | 5,153.7 | 16.4% | 15.6% | | Adjusted EBITDA - ES & Corp ($) | 35% | 1,038.7 | 36.0% | 35.8% | | Adjusted EBITDA - SKSS ($) | 5% | 137.5 | 3.2% | 2.8% | | Adjusted Free Cash Flow ($) | 20% | 480.6 | 29.0% | 27.2% | | TRIR | 20% | 0.49 | 30.0% | 28.0% | | | | | 114.6% | 109.4% |

  30. Performance-Based Cash Bonuses

    SEIP Bonus The individual goals under the SEIP are based on the personal management responsibilities of each such member and may include financial metrics associated with the leader’s area of responsibility, leadership development, cost reductions, reduction of the average duration of the Company’s outstanding receivables, or completion/integration of acquisitions or information technology systems. Each individual goal is weighted and payouts are determined based on the C&HC Committee’s evaluation of performance against the established goals, with no available over-achievement. Additionally each year, a common goal is also established for the SEIP participants. In 2025, this goal was focused on improving the health of the accounts receivables and was established at 5% of each SEIP participant’s base salary. The common goal is in addition to any achievement of the individual goals allowing for up to a total of 105% achievement. The SEIP payout is calculated as follows: SEIP Bonus = Base Salary × SEIP % × SEIP Achievement % (up to 100% for individual targets + up to 5% for the common goal) . The individual goals and common goal for 2025 were set at levels the C&HC Committee believes are sufficiently difficult to achieve in order to provide a significant incentive for participants to drive the Company’s performance. In January 2025, the C&HC Committee reviewed the individual goals and common goal that were established for 2025 under the SEIP bonus and in March 2026, the C&HC Committee approved the SEIP payout achievement as follows: Mr. Dugas: 101%, Mr. Weber: 100%, and Mr. Diderich: 96%. Total MIP Bonus Achievement The following table summarizes the total MIP bonus achievement (Annual MIP and SEIP) for 2025 for the NEOs (amounts in table may not calculate exactly due to rounding):

  31. Performance-Based Cash Bonuses

    | | Salary for Cash Bonus Payout ($) | Annual MIP | | | SEIP | | | Total Combined Cash Bonus ($) | | Name | | % of Salary | Performance Factor | Annual MIP Payout ($) | % of Salary | SEIP Achievement | SEIP Payout ($) | | | | A | B | C | A*B*C | D | E | A*D*E | | | Michael L. Battles | 1,000,000 | 150% | 114.6% | 1,719,000 | — | — | — | 1,719,000 | | Eric W. Gerstenberg | 1,000,000 | 150% | 114.6% | 1,719,000 | — | — | — | 1,719,000 | | Eric J. Dugas | 565,000 | 50% | 109.4% | 309,055 | 80% | 101% | 457,650 | 766,705 | | Brian P. Weber | 630,000 | 50% | 109.4% | 344,610 | 80% | 100% | 503,997 | 848,607 | | Jeroen Diderich | 625,000 | 50% | 109.4% | 341,877 | 80% | 96% | 481,252 | 823,129 | | Alan S. McKim | 900,000 | 150% | 114.6% | 1,547,100 | — | — | — | 1,547,100 |

  32. Performance-Based Cash Bonuses

    The C&HC Committee believes that the goals for Company-wide performance and the SEIP individual and common goals established under the MIP for 2025 were sufficiently difficult to achieve in order to provide a significant incentive for the participants to achieve and exceed the Company’s performance during that year. The C&HC Committee also believes that such goals did not encourage any of the participants to cause the Company to take excessive risks in connection with achieving the goals and that, by including targets for health and safety in the overall Annual MIP bonus goals of the NEOs, the goals were consistent with reducing the Company’s overall risks.

  33. Long-Term Equity Incentives

    Long-Term Equity Incentives The final element of our compensation program for senior executives is long-term equity incentives designed to align the interests of participants with those of the Company’s shareholders and encourage retention of senior executives. All of the equity incentives provided have been in two forms: (i) performance-based restricted shares (“performance shares”), which are earned and become eligible to vest (subject to continued employment) only if the Company satisfies certain predetermined objective performance goals approved by the C&HC Committee prior to the grant date, and (ii) time-vesting restricted shares (“time-vesting shares”), which vest only if the recipient remains employed by the Company through certain specified future dates and which therefore serve as a retention incentive as well as increasing the respective ownership interest of the recipients in the Company during such vesting period. All of the equity grants in 2025 were granted under the Company’s 2020 Stock Incentive Plan. Performance Shares The C&HC Committee grants performance shares as a form of long-term equity incentive with performance goals as described below and additional vesting requirements based on continued employment. In 2025, all of the NEOs received such grants other than Mr. McKim, who does not receive any equity compensation. On January 27, 2025, the C&HC Committee established Adjusted EBITDA and Adjusted EBITDA Margin as the two performance goals (weighted 50% each) for the performance shares granted in 2025 (“2025 Performance Awards”). The C&HC Committee selected these metrics for their direct alignment with the Company’s long-term profitable growth and the generation of shareholder value. Each metric under the 2025 Performance Award has a threshold, target, and maximum as shown in the table below:

  34. Long-Term Equity Incentives

    | Metric | Threshold | Target | Maximum | | Adjusted EBITDA ($ millions) | 1,220.0 | 1,250.0 | 1,310.0 | | Adjusted EBITDA Margin (%) | 19.3% | 19.4% | 19.6% |

  35. Long-Term Equity Incentives

    Each performance metric is evaluated independently. Beginning in 2025, the structure of the performance shares awards has been updated so that performance is measured solely on the Company’s results achieved during the year following the year in which the grant occurs. In prior years, performance awards could be earned based on meeting a metric’s performance goal in either the grant year or the subsequent year. To support a longer‑term performance horizon, awards can no longer be earned for performance achieved in the year of grant. Additionally, to better align with performance award practices among the Company’s peers, the 2025 awards now include a maximum payout opportunity of 200% of target. Shares associated with the 2025 Performance Award may be paid at threshold (50%), target (100%), or maximum (200%) for one or both metrics. Previously, awards included only threshold and target levels, with payouts of 50% and 100%, respectively. The C&HC Committee adopted these changes to more closely reflect market practices, emphasize longer‑term performance, and establish objectives that encourage overachievement to further drive the Company’s growth. Achievement of 2025 Performance Awards will be determined in the first quarter of 2027, based on the Company’s performance in 2026. Any earned shares will vest in two equal, annual installments beginning on March 15, 2027 (subject to the NEOs’ continued employment). If the Company does not achieve at least the threshold level for a particular metric of the 2025 Performance Awards by December 31, 2026, all of the performance shares awarded under the 2025 Performance Award that are eligible to be earned based on achievement of that metric will be forfeited. Performance shares granted have a value equal to a percentage of the individual’s annual base salary. The following table sets forth the 2025 Performance Awards granted to the NEOs, which were granted on February 1, 2025, both as a percentage of their base salary and the number of shares at target:

  36. Long-Term Equity Incentives

    | | Shares Awarded | | | Name | % of Base Salary | # of Shares | | Michael L. Battles | 124.5% | 5,325 | | Eric W. Gerstenberg | 124.5% | 5,325 | | Eric J. Dugas | 120% | 2,924 | | Brian P. Weber | 120% | 3,260 | | Jeroen Diderich | 120% | 3,234 | | Alan S. McKim | — | — |

  37. Long-Term Equity Incentives

    Mr. McKim did not receive any equity awards in 2025 given that his interests are already significantly aligned with those of the other shareholders as the Company’s founder and largest individual shareholder. The share quantity was calculated using the average price for the last ten business days in December 2024 and the shares were granted on February 1, 2025. As noted above, the plan structure for performance awards changed in 2025. Prior to that, the awards could be earned either in the grant year or in the subsequent year. For the performance awards granted in 2024 (“2024 Performance Awards”), the two equally weighted performance goals were Adjusted Return on Invested Capital (“Adjusted ROIC”) and Adjusted EBITDA Margin and any earned shares would vest, subject to continued employment, in either five equal installments beginning on March 15, 2025 (for performance achieved in 2024) or in four equal installments beginning on March 15, 2026 (for performance achieved in 2025). In March 2025, the C&HC Committee determined that the Company achieved the target level for the Adjusted EBITDA Margin goal in 2024, and the 50% of the 2024 Performance Awards subject to this goal began to vest on March 15, 2025 and will continue to vest annually through March 15, 2029. In March 2026, the C&HC Committee determined that the Company did not achieve the threshold level for the ROIC goal in either 2024 or 2025, and the 50% of the 2024 Performance Awards subject to this goal was forfeited on March 13, 2026. On February 1, 2026, the C&HC Committee granted performance awards to each of our NEOs other than Mr. McKim (“2026 Performance Awards”). The 2026 Performance Awards will again be earned based on achievement of equally weighted Adjusted EBITDA and Adjusted EBITDA Margin goals for 2027. The 2026 Performance Awards again have a threshold (50%), target (100%), and maximum (200%) for each metric. To the extent that the 2027 performance goals are achieved, earned shares will vest, subject to continued employment, 50% on March 15, 2028 and 50% on March 15, 2029. Time-Based Shares In addition to the performance shares described above, on February 1, 2025, the C&HC Committee granted time-based shares to the NEOs. The following table sets forth the individual time-based share grants made to the NEOs on February 1, 2025 both as a percentage of their base salary and the number of shares:

  38. Long-Term Equity Incentives

    | | Shares Awarded | | | Name | % of Base Salary | # of Shares | | Michael L. Battles | 256.5% | 11,059 | | Eric W. Gerstenberg | 256.5% | 11,059 | | Eric J. Dugas | 40% | 975 | | Brian P. Weber | 40% | 1,087 | | Jeroen Diderich | 40% | 1,078 | | Alan S. McKim | — | — |

  39. Long-Term Equity Incentives

    The share quantity for the 2025 time-based shares was calculated using an average pri ce for the last ten business days in December 2024 and the shares were granted on February 1, 2025. The time-based shares granted vest in equal annual installments over four years beginning on February 1, 2026 (subject to the NEOs’ continued employment). Mr. McKim did not receive any time-based shares in 2025 given that his interests are already significantly aligned with those of the other shareholders as the Company’s founder and largest individual shareholder.

  40. Policies Related to Timing of Stock Option Grants

    Policies Related to Timing of Stock Option Grants The Company has not granted any stock options for more than ten years. If the Company were to grant any stock options in the future, the C&HC Committee would endeavor not to make any such grants at times when there may be material nonpublic information concerning the Company that might affect the market price of the Company’s common stock. Similarly, it is our practice not to time the release of material nonpublic information based on equity award grant dates or for the purpose of impacting the value of executive compensation.

  41. Clawback Policy

    Clawback Policy The Board adopted a clawback policy that complies with the listing standards of the NYSE effective October 2, 2023 in accordance with Section 10D of the Exchange Act, and the regulations adopted on February 22, 2023 by the SEC under such section. A copy of the clawback policy is filed as Exhibit 97 to our Annual Report on Form 10-K for the year ended December 31, 2025, and the following summary of the provisions of the policy is subject to the full terms of the policy itself. Our clawback policy provides that if the Company is required in the future to prepare an accounting restatement of its financial statements because of the Company’s material noncompliance with any financial reporting requirement under the federal securities laws, the Board will, subject to certain limited exceptions permitted under the final clawback rules, require reimbursement or forfeiture of any “excess incentive compensation,” whether in the form of cash or equity, received by any current or former executive officer of the Company and its subsidiaries as determined by the Board in accordance with Section 10D and such other employees who may from time to time be deemed subject to the policy by the Board (“covered executives”), during the three completed fiscal years immediately preceding the date on which the Company is required to prepare the accounting restatement. For this purpose, “excess incentive compensation” means the amount of incentive compensation that was paid over the amount that would have been paid to the covered executives if it had been based on the restated results, as determined by the Board. Unless the Board determines to itself administer the clawback policy, the policy shall be administered by the C&HC Committee and references therein to the Board shall be deemed references to the C&HC Committee. This clawback policy was effective as of August 30, 2023, the date it was adopted by the Board, and applies to incentive compensation approved, awarded or granted to covered executives on and after that date. With respect to incentive compensation that was approved, awarded or granted to certain executive officers of the Company prior to the effective date of the clawback policy, the Company’s prior clawback policy will remain in effect. Under that prior policy, any cash bonus awarded by the C&HC Committee to any executive officer (as that term is defined in Section 16 of the Exchange Act) in any of the Company’s cash incentive or bonus plans is subject to recoupment if either (i) the Company’s financial statements are restated and the C&HC Committee determines that any misstatement in such financial statements that gave rise to payment of such bonus resulted from such recipient’s gross negligence, intentional misconduct, or fraud or (ii) such recipient causes, in the sole determination of the C&HC Committee, material reputational or economic damage to the Company by reason of such recipient’s violation of any non-competition, non-solicitation, non-disclosure, non-disparagement or similar obligation or such recipient’s gross negligence or violation of any applicable law. In addition, the Company’s 2020 Stock Incentive Plan (under which all equity incentives have been awarded since its adoption in 2020) provides that the C&HC Committee has full authority to implement any policies and procedures necessary to comply with Section 10D of the Exchange Act and any rules promulgated thereunder, and all awards made pursuant to that Plan shall be subject to the clawback policies of the Company adopted from time to time by the Board. Without limiting the foregoing, the C&HC Committee may or shall, to the extent required by the Company’s current or prior clawback policies described above, cancel vesting of outstanding awards and recoup realized value and gains derived from awards to the extent such vesting or gains were derived from such misstated financial results.

  42. Employment, Termination of Employment, and Change of Control Agreements and Arrangements

    Employment, Termination of Employment, and Change of Control Agreements and Arrangements The Company does not have employment agreements with any of its NEOs, although offer letters entered into with NEOs in connection with their initial hiring or subsequent significant changes in their responsibilities typically contain terms relating to initial base salaries, opportunities for potential cash bonuses, and rights to receive grants of restricted shares under the Company’s equity incentive plan. Under the Company’s MIP, in the event of an executive’s death or disability, the executive is entitled to a pro-rated portion of the bonus the executive would have otherwise earned had the executive been employed for the full year based on actual achievement of the performance metrics. In addition, under the MIP, if a Change in Control (as defined in the MIP) occurs after the actual annual incentive bonus to be paid with respect to a plan year has been determined but before such bonus has been paid, such bonus shall be paid immediately in cash, (ii) if a Change in Control occurs after the end of the plan year but before the amount of the actual bonus to be paid has been determined, such bonus shall be immediately determined and paid in cash, and (iii) if a Change in Control occurs during the year, a pro-rata portion of the bonus shall immediately be paid, with the performance criteria deemed to have been satisfied at the midpoint between the threshold and maximum levels. Beginning in 2025, the C&HC Committee approved two key policy changes affecting awards granted under the 2020 Stock Incentive Plan. First, in the event of an executive’s death or disability, all unvested time‑based restricted shares and any earned, but unvested performance‑based restricted shares will vest immediately. In addition, any outstanding unvested and unearned performance‑based restricted shares will be deemed earned and vest at 100% of target. Second, the C&HC Committee approved accelerated vesting of certain unvested shares upon a qualified retirement. A qualified retirement is defined as a retirement in which the individual is (i) at least 55 years old, (ii) has a minimum of 10 years of service with the Company, (iii) provides at least one year’s advance notice of retirement, (iv) to the extent permitted by applicable law, signs a restrictive covenant agreement with restrictions extending for at least one year following termination of employment, and (v) is in good standing at the time notice of retirement is provided and at the time of termination of employment. When these criteria are met, the annual long‑term incentive plan awards become eligible for accelerated vesting. Only performance shares that have been earned as of the retirement date may be accelerated. Any grants made outside the regular annual long‑term incentive cycle (e.g., discretionary or one‑time awards) are not eligible for acceleration. For individuals whose age plus years of service (measured at the time notice of retirement is provided) equals at least 70, 75% of their unvested annual long‑term incentive plan shares, including any earned but unvested performance-based shares, will accelerate and vest upon a qualified retirement. For those whose age plus years of service equals at least 80, 100% of their unvested annual long‑term incentive plan shares, including any earned but unvested performance-based shares, will accelerate and vest upon a qualified retirement. The Company has a Key Employee Retention Plan for certain members of senior management other than Mr. McKim and has entered into Severance Agreements with each of Mr. Battles and Mr. Gerstenberg. Each of the NEOs, in order to receive severance payments, must sign a severance agreement and a confidentiality and non-competition agreement under which, among other matters, such participant agrees not to compete with the Company for a specified period following termination of employment. Under the Key Employee Retention Plan, upon a termination of employment other than for death, Disability, or Cause and not related to a Change of Control (each as defined in the Key Employee Retention Plan and the severance agreement), each covered executive is eligible to receive continued payment to the executive of base salary for one year and continued medical, dental, life insurance, and other benefits, if any, for up to 12 months following termination of employment and, if the employee has not obtained other employment, up to $15,000 in outplacement benefits. Under the Severance Agreements with Mr. Battles and Mr. Gerstenberg, upon a termination of employment other than for death, Disability, or Cause and not related to a Change of Control (as each is defined in the applicable Severance Agreement), each Co-CEO is eligible to receive continued payment of base salary for 24 months and an amount equal to the average of the last two cash bonuses the executive received over the two years immediately prior to the year in which severance has occurred, paid over 24 months. In addition to such severance, each of Mr. Battles and Mr. Gerstenberg is eligible for continued medical, dental, life insurance, and other benefits, if any, for up to 24 months following termination of employment and up to $25,000 in outplacement benefits. Under the Key Employee Retention Plan or the Severance Agreements, as applicable, in the event of a Change of Control, an eligible executive who participates in the Key Employee Retention Plan will receive the same severance benefits as those described above (but the cash payments will be payable in a lump sum) if either (i) the executive does not receive a position equal to the position that the executive held prior to the Change of Control or (ii) the executive accepts a position with the successor corporation after the Change of Control, and, within one year of the Change in Control, (1) the executive’s employment is terminated other than for Cause or (2) the executive's position is changed by the Company or its successor so as not to be equal to his or her position prior to the Change of Control. Under the Company’s 2020 Stock Incentive Plan, upon the occurrence of a Reorganization Event (as defined in the 2020 Stock Incentive Plan) involving the liquidation or dissolution of the Company, except to the extent specifically provided to the contrary in the restricted stock award agreement or any other agreement between a participant and the Company, all restrictions and conditions on all restricted stock awards then outstanding shall automatically be deemed terminated or

  43. Employment, Termination of Employment, and Change of Control Agreements and Arrangements

    satisfied. In addition, under the 2020 Stock Incentive Plan, any stock option or stock appreciation right granted one year or more prior to a Change-in-Control (as defined in the 2020 Stock Incentive Plan) that is neither assumed nor substituted for by the acquirer in connection with any such Change-in-Control shall become fully vested and exercisable immediately prior to the Change-in-Control. Any stock option or stock appreciation right granted less than one year prior to the Change-in-Control that is neither assumed nor substituted for by the acquirer in connection with the Change-in-Control shall, to the extent not previously vested and exercisable, become vested and exercisable immediately prior to the Change-in-Control as to a pro-rated portion of the number of shares originally subject to such award and such award shall terminate with respect to all remaining shares subject thereto. For purposes of determining the number of shares that will become fully vested and exercisable under any performance-based award that is neither assumed nor substituted by the acquirer in connection with any such Change-in-Control, the target level of achievement shall be deemed to apply. Under the 2020 Stock Incentive Plan all outstanding awards other than stock options and stock appreciation rights that are assumed or substituted by the acquirer in connection with such Reorganization Event will become fully vested and all restrictions on such awards will lapse if the participant’s employment is terminated at any time during the 24‑months period following the Reorganization Event either (i) by the acquirer without Cause (as defined in the 2020 Stock Incentive Plan) or (ii) by the participant for Good Reason (as defined in the 2020 Stock Incentive Plan). Any such award that is neither assumed nor substituted by the acquirer in connection with the Change-in-Control shall become fully vested and all restrictions shall be released immediately prior to the Change-in-Control.

  44. 2025 Summary Compensation Table

    2025 Summary Compensation Table For 2025 our NEOs are Michael L. Battles and Eric W. Gerstenberg, our Co-Chief Executive Officers and Co-Presidents, Eric J. Dugas, our Executive Vice President and Chief Financial Officer, Alan S. McKim, our Executive Chairman and Chief Technology Officer, Brian P. Weber, our President of Safety-Kleen Sustainability Solutions, and Jeroen Diderich, our President of Environmental Sales and Services, the three most highly compensated executive officers of the Company and its subsidiaries who were employed by the Company as of December 31, 2025 other than the Co-CEOs and the CFO. The following table sets forth information regarding fiscal years 2025, 2024, and 2023 compensation for our NEOs.

  45. 2025 Summary Compensation Table

    | Name and Principal Position(1) | Year | Salary ($) | Bonus ($) | Stock Awards (2) ($) | Non-Equity Incentive Plan Compensation (3) ($) | All Other Compensation (4) ($) | Total ($) | | Michael L. Battles | 2025 | 1,000,000 | — | 3,197,110 | 1,719,000 | 11,702 | 5,927,812 | | Co-Chief Executive Officer and | 2024 | 900,000 | — | 2,881,028 | 1,493,831 | 11,186 | 5,286,045 | | Co-President | 2023 | 810,000 | — | 2,931,746 | 1,168,875 | 6,691 | 4,917,312 | | Eric W. Gerstenberg | 2025 | 1,000,000 | — | 3,197,110 | 1,719,000 | 13,312 | 5,929,422 | | Co-Chief Executive Officer and | 2024 | 900,000 | — | 2,881,028 | 1,493,831 | 7,986 | 5,282,845 | | Co-President | 2023 | 831,250 | — | 2,931,746 | 1,168,875 | 6,672 | 4,938,543 | | Eric J. Dugas | 2025 | 565,000 | — | 567,821 | 766,705 | 4,627 | 1,904,153 | | Executive Vice President and | 2024 | 425,000 | — | 353,181 | 589,513 | 7,658 | 1,375,352 | | Chief Financial Officer | 2023 | 399,750 | — | 145,738 | 480,571 | 4,560 | 1,030,619 | | Brian P. Weber | 2025 | 630,000 | — | 633,061 | 848,607 | 8,349 | 2,120,017 | | President, Safety-Kleen | 2024 | 576,667 | — | 537,711 | 709,930 | 5,918 | 1,830,226 | | Sustainability Solutions | 2023 | 532,125 | — | 904,466 | 564,582 | 5,414 | 2,006,587 | | Jeroen Diderich | 2025 | 625,003 | — | 627,935 | 823,129 | 6,567 | 2,082,634 | | President, Environmental Sales | 2024 | 386,278 | 100,000 | 2,382,490 | 869,431 | 101,232 | 3,839,431 | | and Services | | | | | | | | | Alan S. McKim | 2025 | 900,000 | — | — | 1,547,100 | 18,797 | 2,465,897 | | Executive Chairman and | 2024 | 900,000 | — | — | 1,493,831 | 16,354 | 2,410,185 | | Chief Technology Officer | 2023 | 991,250 | — | — | 1,287,386 | 17,928 | 2,296,564 |

  46. 2025 Summary Compensation Table

    (1) The respective principal position of each NEO is stated as of December 31, 2025. (2) Represents the aggregate grant date fair value, as computed in accordance with FASB ASC Topic 718. For a description of the assumptions used in determining these values, see Note 16, “Stock-Based Compensation” to the financial statements in the Company’s Annual Report on Form 10-K for the year ended December 31, 2025. With respect to the performance-based restricted stock grants, the value in the table above is based on the probable outcome of the applicable performance conditions as of the grant date, which was 50% of target as of the grant date. The value of such performance-based restricted stock awards granted in 2025 assuming the target achievement of the performance conditions is as follows: Mr. Battles - $1,240,725 and Mr. Gerstenberg - $1,240,725, Mr. Dugas - $681,292, Mr. Weber - $759,580, and Mr. Diderich - $753,522. Mr. McKim was not granted any performance-based equity awards in 2025. (3) Amounts reported in the Non-Equity Incentive Plan Compensation represent annual cash incentive awards pursuant to the MIP, as such plans have been described in the accompanying Compensation Discussion and Analysis – Performance-Based Cash Bonuses. The Company did not have any other non-equity incentive plan, long-term cash incentive plan, pension plan, or deferred compensation plan under which any of the NEOs participated in the periods presented. (4) Amounts for 2025 consist of matching 401(k) Plan contributions, Company contributions to health savings plans, and group term life insurance benefits, all of which are available to all other full-time employees on a nondiscriminatory basis.

  47. Grants of Plan-Based Awards

    Grants of Plan-Based Awards The following table sets forth, for each of the NEOs, (i) the threshold, target, and maximum potential cash bonuses, subject to achievement of certain Company and/or individual performance criteria in 2025, and (ii) the time-vesting shares and performance-based shares granted during 2025 under the Company’s 2020 Stock Incentive Plan. The actual amounts of the cash bonuses paid for 2025 under the MIP to each of the NEOs are presented in the Non-Equity Incentive Plan Compensation column in the 2025 Summary Compensation Table above. During 2025, the only equity awards made to the NEOs were the time-vesting and performance-based shares presented in the following table, and no stock options, stock appreciation rights, or similar equity awards were issued, repriced, or otherwise modified during 2025.

  48. Grants of Plan-Based Awards

    | | | Estimated Possible Payouts Under Non-Equity Incentive Plan Awards (1) | | | Estimated Possible Payouts Under Equity Incentive Plan Awards (2) | | | All Other Stock Awards: Number of Shares of Stock or Units (#) | Grant Date Fair Value of Stock Awards (3) ($) | | Name | Grant Date | Threshold ($) | Target ($) | Maximum ($) | Threshold (#) | Target (#) | Maximum (#) | | | | Michael L. Battles | N/A | 750,000 | 1,500,000 | 2,250,000 | | | | | | | | 2/1/2025 | | | | 2,663 | 5,325 | 10,650 | | 620,363 | | | 2/1/2025 | | | | | | | 11,059 | 2,576,747 | | Eric W. Gerstenberg | N/A | 750,000 | 1,500,000 | 2,250,000 | | | | | | | | 2/1/2025 | | | | 2,663 | 5,325 | 10,650 | | 620,363 | | | 2/1/2025 | | | | | | | 11,059 | 2,576,747 | | Eric J. Dugas | N/A | 565,000 | 734,500 | 847,500 | | | | | | | | 2/1/2025 | | | | 1,462 | 2,924 | 5,848 | | 340,646 | | | 2/1/2025 | | | | | | | 975 | 227,175 | | Brian P. Weber | N/A | 630,000 | 819,000 | 945,000 | | | | | | | | 2/1/2025 | | | | 1,630 | 3,260 | 6,520 | | 379,790 | | | 2/1/2025 | | | | | | | 1,087 | 253,271 | | Jeroen Diderich | N/A | 625,000 | 812,500 | 937,500 | | | | | | | | 2/1/2025 | | | | 1,617 | 3,234 | 6,468 | | 376,761 | | | 2/1/2025 | | | | | | | 1,078 | 251,174 | | Alan S. McKim | N/A | 675,000 | 1,350,000 | 2,025,000 | | | | | |

  49. Grants of Plan-Based Awards

    (1) Amounts include both the Annual MIP Bonus and the SEIP Bonus (with respect to Mr. Dugas, Mr. Weber and Mr. Diderich) as discussed in Compensation Discussion and Analysis-Performance-Based Cash Bonuses above. SEIP Bonuses are included at 100% of target achievement in all columns. (2) The amounts reported represent the threshold, target, and maximum number of performance-based restricted shares granted to NEOs in 2025. These awards will vest and be earned only if certain performance goals are achieved as described in the Compensation Discussion and Analysis - Long-Term Equity Incentives above. (3) The grant date fair values of restricted stock awards are computed in accordance with FASB ASC Topic 718. For a description of the assumptions used in determining these values, see Note 17, “Stock-Based Compensation,” to the financial statements in the Company’s Annual Report on Form 10-K for the year ended December 31, 2025. The values reported for the performance based restricted stock awards represent the grant date fair values of such stock awards assuming the probable outcome of the performance conditions. The values of such awards assuming the maximum achievement of the applicable performance conditions are reported in footnote 2 to the 2025 Summary Compensation Table above.

  50. Outstanding Equity Awards at Fiscal Year-End

    Outstanding Equity Awards at Fiscal Year-End The following table sets forth the outstanding equity awards held at December 31, 2025 by each of the NEOs, which consisted of (i) unvested time-vesting restricted shares, (ii) performance-based restricted shares for which the performance goals had been satisfied but remained subject to vesting based on continued employment requirements, and (iii) performance-based restricted shares for which the performance goals had not yet been satisfied but remained eligible for potential future vesting upon satisfaction of both performance goals and continued employment requirements.

  51. Outstanding Equity Awards at Fiscal Year-End

    | | | Stock Awards | | | | | Name | Grant Date | Number of Shares or Units of Stock that Have Not Vested (#) | Market Value of Shares or Units of Stock that Have Not Vested (1) ($) | Equity Incentive Plan Awards: | | | | | | | Number of Unearned Shares, Units or Other Rights That Have Not Vested (#) | Market or Payout Value of Unearned Shares, Units or Other Rights that Have Not Vested (1) ($) | | Michael L. Battles | 7/1/2021 | 1,540(2) | 361,099 | — | — | | | 7/1/2021 | 593(3) | 139,047 | — | — | | | 2/7/2022 | 2,902(4) | 680,461 | — | — | | | 2/7/2022 | 1,117(3) | 261,914 | — | — | | | 2/1/2023 | 1,464(5) | 343,279 | — | — | | | 2/1/2023 | 13,470(6) | 3,158,446 | — | — | | | 2/1/2024 | 1,732(7) | 406,119 | — | — | | | 2/1/2024 | 11,619(6) | 2,724,423 | — | — | | | 2/1/2025 | 11,059(8) | 2,593,114 | — | — | | | 2/1/2025 | — | — | 2,663(9) | 624,303 | | Eric W. Gerstenberg | 7/1/2021 | 1,166(2) | 273,404 | — | — | | | 2/7/2022 | 2,196(4) | 514,918 | — | — | | | 2/1/2023 | 1,464(5) | 343,279 | — | — | | | 2/1/2023 | 13,470(6) | 3,158,446 | — | — | | | 2/1/2024 | 1,732(7) | 406,119 | — | — | | | 2/1/2024 | 11,619(6) | 2,724,423 | — | — | | | 2/1/2025 | 11,059(8) | 2,593,114 | — | — | | | 2/1/2025 | — | — | 2,663(9) | 624,303 | | Eric J. Dugas | 7/1/2021 | 724(2) | 169,764 | — | — | | | 7/1/2021 | 198(3) | 46,427 | — | — | | | 2/7/2022 | 1,474(4) | 345,624 | — | — | | | 2/7/2022 | 402(3) | 94,261 | — | — | | | 2/1/2023 | 894(5) | 209,625 | — | — | | | 2/1/2023 | 1,116(3) | 261,680 | — | — | | | 2/1/2024 | 1,059(7) | 248,314 | — | — | | | 2/1/2024 | 722(3) | 169,295 | — | — | | | 2/1/2025 | 975(8) | 228,618 | — | — | | | 2/1/2025 | — | — | 1,462(9) | 342,810 |

  52. Outstanding Equity Awards at Fiscal Year-End

    | | | Stock Awards | | | | | Name | Grant Date | Number of Shares or Units of Stock that Have Not Vested (#) | Market Value of Shares or Units of Stock that Have Not Vested (1) ($) | Equity Incentive Plan Awards: | | | | | | | Number of Unearned Shares, Units or Other Rights That Have Not Vested (#) | Market or Payout Value of Unearned Shares, Units or Other Rights that Have Not Vested (1) ($) | | Brian P. Weber | 7/1/2021 | 1,260(2) | 295,445 | — | — | | | 7/1/2021 | 420(3) | 98,482 | — | — | | | 2/7/2022 | 2,376(4) | 557,124 | — | — | | | 2/7/2022 | 792(3) | 185,708 | — | — | | | 2/1/2023 | 1,263(5) | 296,148 | — | — | | | 2/1/2023 | 1,926(3) | 451,608 | — | — | | | 2/1/2023 | 3,000(6) | 703,440 | — | — | | | 2/1/2024 | 1,495(7) | 350,548 | — | — | | | 2/1/2024 | 1,246(3) | 292,162 | — | — | | | 2/1/2025 | 1,087(8) | 254,880 | — | — | | | 2/1/2025 | — | — | 1,630(9) | 382,202 | | Jeroen Diderich | 6/1/2024 | 7,334(10) | 1,719,676 | — | — | | | 2/1/2025 | 1,078(8) | 252,769 | — | — | | | 2/1/2025 | — | — | 1,617(9) | 379,154 | | Alan S. McKim | 7/1/2021 | 2,776(2) | 650,916 | — | — | | | 2/7/2022 | 5,231(4) | 1,226,565 | — | — |

  53. Outstanding Equity Awards at Fiscal Year-End

    (1) The market or payout value of the restricted stock is computed using the closing stock price as of December 31, 2025, the last trading day of 2025, of $234.48. (2) Represents shares earned under performance-based awards that vest on July 1, 2026. (3) Represents an annual grant of time-vesting shares that vest 60% on the third anniversary of the grant date and 20% on each of the fourth and fifth anniversaries of the grant date. (4) Represents shares earned under performance-based awards that vest ratably on March 15, 2026 and March 15, 2027. (5) Represents shares earned under performance-based awards that vest ratably on March 15, 2026, March 15, 2027, and March 15, 2028. (6) Represents an annual grant of time vesting shares that vest ratably on the anniversary of the grant date over five years. (7) Represents shares earned under performance-based awards that vest ratably on March 15, 2026, March 15, 2027, March 15, 2028 and March 15, 2029. (8) Represents a grant of time-vesting shares vesting ratably on the anniversary of the grant date over four years. (9) Represents performance-based awards granted in 2025 which are eligible to be earned based upon achievement of performance metrics in 2026. The amounts reported represent the threshold level of achievement as 2025 actual performance of the performance metrics was below threshold. (10) Represents a grant of time-vesting shares vesting ratably on the anniversary of the grant date over three years.

  54. Option Exercises and Stock Vested

    Option Exercises and Stock Vested The Company has not granted any stock options to its NEOs for more than ten years. The following table shows for each NEO the aggregate number of restricted shares that vested during 2025, including time-based shares and performance-based shares, and the value of those shares upon vesting based on the closing price of the Company's common stock on the vesting date. The low and high closing prices of the Company's common stock in 2025 were $182.10 and $250.43, respectively. The closing price on December 31, 2025, the last trading day of 2025, was $234.48.

  55. Option Exercises and Stock Vested

    | | Stock Awards | | | Name | Number of Shares Acquired on Vesting (#) | Value Realized on Vesting ($) | | Michael L. Battles | 14,607 | 3,297,321 | | Eric W. Gerstenberg | 16,843 | 3,839,358 | | Eric J. Dugas | 4,834 | 1,059,479 | | Brian P. Weber | 6,513 | 1,429,964 | | Jeroen Diderich | 3,666 | 831,412 | | Alan S. McKim | 5,391 | 1,141,628 |

  56. Potential Payments Upon Termination or Change of Control

    Potential Payments Upon Termination or Change of Control The following table sets forth the amounts that would potentially become payable for each of the NEOs (subject to certain conditions, including compliance with severance agreements) under existing plans and arrangements if the executive's employment had been terminated under certain circumstances on December 31, 2025. The amounts reflect the executive's level of compensation and term of service as of December 31, 2025,

  57. Potential Payments Upon Termination or Change of Control

    | Name | Termination Without Cause not in Connection with a Change of Control ($) | Involuntary Termination in Connection with a Change of Control (1) ($) | Death or Disability ($) | Dissolution or Liquidation ($) | Qualified Retirement (6) ($) | | Michael L. Battles | | | | | | | Base Salary (2) | 2,000,000 | 2,000,000 | — | — | — | | Performance Based Cash Bonus (3) | 3,050,353 | 3,050,353 | 3,050,353 | — | — | | Stock Awards (4) | — | 12,424,392 | 12,424,392 | 12,424,392 | — | | Other Compensation (5) | 87,679 | 87,679 | — | — | — | | Eric W. Gerstenberg | | | | | | | Base Salary (2) | 2,000,000 | 2,000,000 | — | — | — | | Performance Based Cash Bonus (3) | 3,050,353 | 3,050,353 | 3,050,353 | — | — | | Stock Awards (4) | — | 11,770,193 | 11,770,193 | 11,770,193 | 7,420,589 | | Other Compensation (5) | 89,450 | 89,450 | — | — | — | | Eric J. Dugas | | | | | | | Base Salary (2) | 565,000 | 565,000 | — | — | — | | Performance Based Cash Bonus (3) | 766,705 | 766,705 | 766,705 | — | — | | Stock Awards (4) | — | 2,769,678 | 2,769,678 | 2,769,678 | — | | Other Compensation (5) | 42,364 | 42,364 | — | — | — | | Brian P. Weber | | | | | | | Base Salary (2) | 630,000 | 630,000 | — | — | — | | Performance Based Cash Bonus (3) | 848,607 | 848,607 | 848,607 | — | — | | Stock Awards (4) | — | 4,688,193 | 4,688,193 | 4,688,193 | 2,527,225 | | Other Compensation (5) | 47,160 | 47,160 | — | — | — | | Jeroen Diderich | | | | | | | Base Salary (2) | 625,003 | 625,003 | — | — | — | | Performance Based Cash Bonus (3) | 823,129 | 823,129 | 823,129 | — | — | | Stock Awards (4) | — | 2,730,754 | 2,730,754 | 2,730,754 | — | | Other Compensation (5) | 45,803 | 45,803 | | | — | | Alan S. McKim | | | | | | | Base Salary (2) | — | — | — | — | — | | Performance Based Cash Bonus (3) | 1,547,100 | 1,547,100 | 1,547,100 | — | 1,547,100 | | Stock Awards (4) | — | 1,877,481 | 1,877,481 | 1,877,481 | — |

  58. Potential Payments Upon Termination or Change of Control

    (1) Assumes that restricted stock awards are assumed in connection with a Change of Control. (2) Base salary payments are made over a one-year period (two years for the Co-CEOs) in accordance with the Key Employee Retention Plan and/or severance agreements, provided, however, that base salary payments made to the Co-CEOs in the event of an involuntary termination with a Change of Control are payable in a lump sum. Mr. McKim is not a participant in the Key Employee Retention Plan. (3) The MIP Bonus payment is calculated based on the level of achievement of the relevant performance criteria for 2025 as determined by the C&HC Committee on March 6, 2026 and is payable in a lump sum. For Mr. Battles and Mr. Gerstenberg, the severance agreements also provide for a bonus payment in the amount of the average of the last two annual cash bonuses the executive received. (4) Assumes restricted stock awards are assumed in connection with the Change of Control and assumes target level for any unearned performance-based awards. Upon death or Disability, vesting for all restricted stock awards accelerates, with unearned performance-based awards deemed earned at the target level of achievement. The restricted share awards are valued using the closing stock price as of December 31, 2025, the last trading day of the year, of $234.48. (5) Other compensation represents continued medical, dental, vision, life insurance benefits, and outplacement services that are provided to the employee at termination in accordance with the Key Employee Retention Plan or applicable severance agreement. Amounts are estimated based upon 2025 benefit costs (24 months for Mr. Battles and Mr. Gerstenberg and 12 months for Mr. Dugas, Mr. Weber and Mr. Diderich). (6) Messrs. Gerstenberg, Weber, and McKim meet the age and tenure requirements under the Company’s qualified new retirement policy (fully described in the Employment, Termination of Employment, and Change of Control Agreements and Arrangements section above; however, none has satisfied the required one‑year notice or other conditions. The values shown assume all requirements were met as of December 31, 2025 and reflect accelerated vesting of certain unvested shares. Had each met all the requirements and retired December 31, 2025, 31,647 shares, 10,778 shares, and 8,007 shares, respectively, would have vested.

  59. CEO Pay Ratio Information

    CEO Pay Ratio Information The SEC requires disclosure of the relationship between the annual total compensation of our Chief Executive Officer (“CEO”) and our median employee. For 2025, the average annual total compensation of our Co-CEOs was $5,928,617. The annual total compensation of the median employee identified was $86,500, resulting in a CEO pay ratio of approximately 69:1. To calculate the ratio above, we used the same median employee that we had identified as of December 31, 2023 because there have been no significant changes in the employee population or compensation arrangements that would significantly impact the pay ratio this year. Our median employee has been identified from a list of Company active employees located in the United States, Canada and India, whether employed on a full-time, part-time or temporary basis as of December 31, 2023, excluding our Co-CEOs. Specifically, to calculate the median employee in 2023, we converted the earnings of each listed employee to U.S. Dollars at an appropriate exchange rate for non-U.S. employees, and annualized for any full-time or part-time employee who did not work for the Company for the entire year. We did not apply any cost-of-living adjustments, nor did we use any form of statistical sampling. For the 2025 pay ratio calculation, we recalculated the median employee’s compensation for 2025 in accordance with SEC Regulation S-K, Item 402(c)(2)(x) requirements for reporting total compensation in the Summary Compensation Table, and then compared the 2025 compensation of such median employee to the average 2025 compensation of our Co-CEOs as reported in the Summary Compensation Table earlier in this proxy statement. In their roles as Co-CEOs, Mr. Battles and Mr. Gerstenberg have the same annual total compensation (other than a small difference in their All Other Compensation amounts).

  60. PAY VERSUS PERFORMANCE

    PAY VERSUS PERFORMANCE In accordance with the SEC’s disclosure requirements regarding pay versus performance (“PVP”), the following information is being provided to illustrate the relationship between the Compensation Actually Paid (calculated in accordance with Item 402(v) of Regulation S-K) (“CAP”) to our NEOs and certain financial performance measures of the Company. For information regarding how the C&HC Committee makes its compensation decisions, see Compensation Discussion and Analysis and Advisory Vote on Executive Compensation earlier in this proxy statement.

  61. Pay Versus Performance Table

    Pay Versus Performance Table The following table sets forth information concerning the compensation of our principal executive officer (“PEO”) and other NEOs for each of the fiscal years ended December 31, 2025, 2024, 2023, 2022 and 2021, and our financial performance for each of such fiscal years as computed in accordance with SEC rules. Specifically, the table includes the Summary Compensation Table (“SCT”) Totals and CAP for compensation to our PEOs and an average for our Non-PEO NEOs.

  62. Pay Versus Performance Table

    | | PEO McKim (1) | | Co-PEO Battles (1) | | Co-PEO Gerstenberg (1) | | Average SCT Total for Non-PEO NEOs(3)(4) ($) | Average CAP to Non-PEO NEOs(3)(9) ($) | Value of Initial Fixed $100 Investment Based On: | | | | | Year | SCT Total(2) ($) | CAP(9) ($) | SCT Total(2) ($) | CAP(9) ($) | SCT Total(2) ($) | CAP(9) ($) | | | TSR(5) ($) | Peer Group TSR(6) ($) | Net Income ('000)(7) ($) | Adjusted EBITDA ('000)(8) ($) | | 2025 | — | — | 5,927,812 | 6,042,760 | 5,929,422 | 6,059,705 | 2,143,175 | 2,134,404 | 307.97 | 178.04 | 390,974 | 1,169,939 | | 2024 | — | — | 5,286,045 | 8,062,035 | 5,282,845 | 8,209,001 | 2,399,973 | 2,991,475 | 302.30 | 164.99 | 402,299 | 1,116,934 | | 2023 | 2,296,564 | 3,620,475 | 4,917,312 | 9,168,758 | 4,938,543 | 10,246,152 | 1,344,687 | 3,379,706 | 229.26 | 140.22 | 377,856 | 1,012,570 | | 2022 | 6,241,356 | 6,773,049 | — | — | — | — | 2,755,014 | 3,349,545 | 149.94 | 113.50 | 411,744 | 1,022,128 | | 2021 | 5,612,724 | 6,601,096 | — | — | — | — | 2,931,679 | 3,736,275 | 131.10 | 129.58 | 203,247 | 676,606 |

  63. Pay Versus Performance Table

    (1) During the period from January 1, 2023 through March 31, 2023 and for all of 2022 and 2021, the Company had one PEO, namely Alan S. McKim. Effective March 31, 2023, Michael L. Battles (who had previously served as the Company's Chief Financial Officer) and Eric. W. Gerstenberg (who had previously served as the Company's Chief Operating Officer) were appointed as the Company's Co-Chief Executive Officers, and served concurrently in that capacity for the remainder of 2023 and for all of 2024 and 2025. (2) The dollar amounts reported in this column are the amounts of total compensation reported for Mr. McKim, Mr. Battles or Mr. Gerstenberg in the “Total” column of the Summary Compensation Table for years in which they held the role of PEO. (3) For 2025, the Non-PEO NEOs whose average compensation is reported in this column included Mr. Dugas, Mr. Weber, Mr. Diderich and Mr. McKim. For 2024, the Non-PEO NEOs whose average compensation is reported in this column included Mr. Dugas, Mr. Diderich, Mr. McKim, and Sharon M. Gabriel. For 2023, the Non-PEO NEOs whose average compensation is reported in this column include Mr. Dugas, Ms. Gabriel, Mr. Weber, and Robert E. Speights. For each of 2022 and 2021 the Non-PEO NEOs whose average compensation is reported in this column include Mr. Battles, Mr. Gerstenberg, Mr. Weber, and Mr. Speights. (4) The dollar amounts reported in this column are the average of the Non-PEO NEOs for each corresponding year in the “Total” column of the Summary Compensation Table. (5) Reflects total shareholder return (“TSR”) based on a fixed investment of $100 on December 31, 2020. (6) Represents the weighted peer group TSR based on a fixed investment of $100 on December 31, 2020. For each of the five fiscal years presented in the table above, the peer group was composed of ABM Industries Incorporated, Advanced Drainage Systems, Inc., APi Group Corporation, Chemed Corporation, The Chemours Company, Darling Ingredients, Inc., Ecolab Inc., EMCOR Group, Inc., Enviri Corporation, GFL Environmental, Inc., Huntsman Corporation, Iron Mountain Inc., KBR, Inc, Republic Services, Inc., Rollins, Inc., Tetra Tech, Inc., The Chemours Company, Waste Connections, Inc., and Waste Management, Inc. Although Stericycle was included in the Company’s peer group for compensation benchmarking purposes for both 2024 and 2025, it was excluded from the TSR calculation in the table because it was acquired by Waste Management in 2024. (7) The dollar amounts reported represent the amount of net income reflected in the Company’s audited financial statements for the applicable fiscal year. (8) Adjusted EBITDA is defined and reconciled to the Company’s net income in Appendix A: Reconciliation of GAAP Measure to Corresponding Non-GAAP Measures earlier in this proxy statement. (9) CAP is calculated in accordance with the Item 402(v) of Regulation S-K. Reconciliations of Summary Compensation Table data to CAP for fiscal 2025, 2024, 2023, 2022, and 2021 for the PEOs and the Non-PEO NEOs are included in the tables below. Mr. McKim was not a PEO during 2025 or 2024 and accordingly, there are no amounts included in that column of the PEO (Alan S. McKim) table. Mr. McKim is a Non-PEO NEO in 2025 and 2024 so his amounts are included therein.

  64. Pay Versus Performance Table

    | | PEO (Alan S. McKim) | | | | | | Year | 2025 | 2024 | 2023 | 2022 | 2021 | | Summary Compensation Table Total Compensation | $— | $— | $2,296,564 | $6,241,356 | $5,612,724 | | Less: Grant Date Fair Value of Stock Awards (from Summary Compensation Table) | — | — | — | 1,199,998 | 1,293,846 | | Add: | | | | | | | Change in Fair Value of Awards Granted During Year and Outstanding and Unvested as of Year-End | — | — | — | 1,492,575 | 1,384,608 | | Change in Fair Value of Prior Year Awards Unvested as of Year-End | — | — | 1,134,728 | 159,314 | 150,020 | | Change in Fair Value of Prior Year Awards that Vested During Year | — | — | 189,183 | 79,802 | 747,590 | | Total Additions to Compensation Actually Paid | — | — | 1,323,911 | 1,731,691 | 2,282,218 | | Compensation Actually Paid | $— | $— | $3,620,475 | $6,773,049 | $6,601,096 | | | Co-PEO (Michael L. Battles) | | | | | | Year | 2025 | 2024 | 2023 | 2022 | 2021 | | Summary Compensation Table Total Compensation | $5,927,812 | $5,286,045 | $4,917,312 | $— | $— | | Less: Grant Date Fair Value of Stock Awards (from Summary Compensation Table) | 3,197,110 | 2,881,028 | 2,931,746 | — | — | | Add: | | | | | | | Change in Fair Value of Awards Granted During Year and Outstanding and Unvested as of Year-End | 3,217,535 | 4,339,520 | 5,086,269 | — | — | | Change in Fair Value of Prior Year Awards Unvested as of Year-End | 158,857 | 1,799,853 | 1,250,254 | — | — | | Change in Fair Value of Prior Year Awards that Vested During Year | (64,334) | 345,520 | 846,669 | — | — | | Change in Fair Value of Prior Year Awards that Forfeited During Year | — | (827,875) | — | — | — | | Total Additions to Compensation Actually Paid | 3,312,058 | 5,657,018 | 7,183,192 | — | — | | Compensation Actually Paid | $6,042,760 | $8,062,035 | $9,168,758 | $— | $— | | | Co-PEO (Eric W. Gerstenberg) | | | | | | Year | 2025 | 2024 | 2023 | 2022 | 2021 | | Summary Compensation Table Total Compensation | $5,929,422 | $5,282,845 | $4,938,543 | $— | $— | | Less: Grant Date Fair Value of Stock Awards (from Summary Compensation Table) | 3,197,110 | 2,881,028 | 2,931,746 | — | — | | Add: | | | | | | | Change in Fair Value of Awards Granted During Year and Outstanding and Unvested as of Year-End | 3,217,535 | 4,339,520 | 5,086,268 | — | — | | Change in Fair Value of Prior Year Awards Unvested as of Year-End | 146,748 | 1,769,034 | 1,792,496 | — | — | | Change in Fair Value of Prior Year Awards that Vested During Year | (36,890) | 526,505 | 1,360,591 | — | — | | Change in Fair Value of Prior Year Awards that Forfeited During Year | — | (827,875) | — | — | — | | Total Additions to Compensation Actually Paid | 3,327,393 | 5,807,184 | 8,239,355 | — | — | | Compensation Actually Paid | $6,059,705 | $8,209,001 | $10,246,152 | $— | $— |

  65. Pay Versus Performance Table

    | | Average of Non-PEO NEOs | | | | | | Year | 2025 | 2024 | 2023 | 2022 | 2021 | | Summary Compensation Table Total Compensation | $2,143,175 | $2,399,973 | $1,344,687 | $2,755,014 | $2,931,679 | | Less: Grant Date Fair Value of Stock Awards (from Summary Compensation Table) | 457,204 | 908,296 | 342,733 | 1,371,984 | 1,604,777 | | Add: | | | | | | | Change in Fair Value of Awards Granted During Year and Outstanding and Unvested as of Year-End | 460,108 | 1,204,668 | 1,281,296 | 1,706,493 | 1,643,335 | | Change in Fair Value of Prior Year Awards Unvested as of Year-End | 46,648 | 429,686 | 844,916 | 325,300 | 543,138 | | Change in Fair Value of Prior Year Awards that Vested During Year | (58,323) | 113,946 | 251,540 | (65,278) | 318,653 | | Change in Fair Value of Prior Year Awards that Forfeited During Year | — | (248,502) | — | — | (95,753) | | Total Additions to Compensation Actually Paid | 448,433 | 1,499,798 | 2,377,752 | 1,966,515 | 2,409,373 | | Compensation Actually Paid | $2,134,404 | $2,991,475 | $3,379,706 | $3,349,545 | $3,736,275 |

  66. Graphical Description of Pay Versus Performance

    Graphical Description of Pay Versus Performance In accordance with the SEC's PVP rules, we are also providing the following graphical illustrations of the relationship between the information presented in the Pay Versus Performance Table above. The following chart sets forth the relationship between CAP for the PEO (which, for years when more than one individual held the role, represents the average of the total annual compensation paid for those PEOs), and, on average, to the other NEOs, and the Company’s TSR and that of our peer group over the five most recently completed fiscal years.

  67. PEO and Average Other NEO Compensation Actually Paid Versus Clean Harbors TSR

    PEO and Average Other NEO Compensation Actually Paid Versus Clean Harbors TSR The following chart sets forth the relationship between CAP for the PEO (which, for years when more than one individual held the role, represents the average of the total annual compensation paid for those PEOs), and on average to the other NEOs, and the Company's net income during the five most recently completed fiscal years.

  68. PEO and Average Other NEO Compensation Actually Paid Versus Clean Harbors Net Income

    PEO and Average Other NEO Compensation Actually Paid Versus Clean Harbors Net Income The following chart sets forth the relationship between CAP for the PEO (which, for years when more than one individual held the role, represents the average of the total annual compensation paid for those PEOs), and, on average, the other NEOs and the Company's Adjusted EBITDA during the five most recently completed fiscal years.

  69. PEO and Average Other NEO Compensation Actually Paid Versus Clean Harbors Adjusted EBITDA

    PEO and Average Other NEO Compensation Actually Paid Versus Clean Harbors Adjusted EBITDA