Martha Thomsen is an experienced environmental litigator and advisor who helps clients navigate complex litigation and evolving regulations.

"Martha's judgment makes her stand out" – Chambers USA 2024

Environmental Litigation Work

Martha's litigation practice extends from pre-litigation resolutions through all stages of lawsuits, including discovery, motions practice, trial, and appeal. Martha has particular experience in highly technical suits involving waste and water issues, including claims arising under the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) and the Resource Conservation and Recovery Act (RCRA). As part of her litigation and CERCLA work, Martha engages with experts and consultants on cost, allocation, and remediation issues.

Select recent cases include: arguing and winning a motion to dismiss a state's natural resource damages (NRD) claims against a manufacturing company; participating on the CERCLA trial team for one of the country's first ever trials that was converted from in-person to virtual mid-spring 2020 and securing cost recovery from the Government on behalf of an oil-and-gas company; and representing several companies in ongoing litigation addressing responsibility for cleanup costs at a Superfund Site estimated to cost more than $2 billion.

Regulatory Compliance and Engagement with State and Federal Agencies

Martha also helps clients navigate compliance with evolving state and federal environmental laws and represents clients before environmental agencies. She takes a holistic approach to regulatory compliance issues that accounts for short-term and long-term client planning, agency and other stakeholder positions, and technical compliance criteria and requirements. As part of this work, Martha engages directly with state and federal agencies to advocate on behalf of clients, clarify agency positions, and engage in formal and informal dispute resolution.

This work spans a variety of environmental statutes, including CERCLA and RCRA as well as the Clean Water Act (CWA), wildlife, and state laws. She also works with clients on renewable and clean energy projects.

Particular areas of experience include coal combustion residuals (CCR) liability and regulatory issues, PFAS, and as well as renewable and clean energy projects. With respect to CCR work, Martha helps power companies navigate a constantly shifting regulatory landscape through counseling, risk management, advising on prospective regulation, and agency engagement.

Select recent work includes: advising numerous power companies on CCR regulatory compliance; representing several power companies on CCR Part A/Part B applications; representing a power company in dispute resolution with a state agency regarding the scope of CCR-related cleanup and associated financial assurance, resulting in a significant reduction in financial assurance requirements; and advising several companies in a variety of industries on ongoing state and federal cleanups.

In 2021, Martha was recognized both by Chambers USA as an environmental "Associate to Watch" and by Bloomberg Law as a "Fresh Face to Know in Environmental Law." In 2022, following her promotion to Partner, Martha was recognized by Chambers USA as "Up & Coming," and in 2024, Martha was ranked by Chambers USA for Environment in D.C.

Prior to joining Baker Botts in 2012, Martha interned for the U.S. Department of Justice. She also worked as a legal research assistant at the University of Michigan in the area of liability insurance. Prior to law school, she worked for Foster Wheeler in Abu Dhabi.