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Jonathan Martel concentrates his practice on Clean Air Act and related matters, including regulatory and compliance counseling, participation in EPA rulemaking activities, government and citizen enforcement actions, appellate litigation challenges to rules, and other litigation matters. Jonathan's recent work includes representation of automotive, engine, nonroad equipment, railroad, gasoline, renewable fuel, natural gas, fertilizer, chemical, and other diversified producers and manufacturers. He appears regularly before U.S. EPA, the various EPA regional offices, and various state agencies, including the California Air Resources Board. He served for several years in the Office of General Counsel of the U.S. Environmental Protection Agency (EPA). While at the EPA, he was involved primarily in the implementation of the Clean Air Act Amendments of 1990.

Jonathan has been an adjunct professor of law at Georgetown University Law Center, where he taught courses on the Clean Air Act and environmental law, and speaks widely on webinars and at professional conferences and law schools. He has contributed the Clean Air Act chapter to the American Bar Association's book Global Climate Change and U.S. Law, a chapter on the fuels provisions of the Clean Air Act for the American Bar Association's Handbook for the Clean Air Act, the transportation chapter for the American Bar Association book, The Law of Clean Energy, and a chapter explaining key principles of climate risk for the forthcoming ABA Book on Law of ESG.

Jonathan's air quality work includes representation of clients with respect to both stationary and mobile sources of air emissions.

With respect to mobile sources, Jonathan has one of the leading practices representing automobile, engine, equipment, and fuel manufacturers in compliance and enforcement matters under Title II of the Clean Air Act and parallel California requirements, as well as fuel economy rules administered jointly by the National Highway Traffic Safety Administration and EPA. He regularly assists in addressing vehicle and engine certification issues, defect reporting and recalls, importation, alternative fuel and technology issues, labeling and exemption issues, and enforcement matters. He has also represented manufacturers in rulemaking proceedings and litigation regarding those rules, litigation regarding preemption of state regulation, and consumer class action and tort claims relating to air emissions from mobile sources. Regarding fuels, he has assisted oil and gasoline blending in compliance and enforcement matters concerning gasoline regulations, and the renewable fuels industry with regard to EPA and California rulemaking and related litigation.

With respect to stationary sources, Jonathan assists in addressing, among other topics, permit issues, including New Source Review and New Source Performance Standards applicability and compliance; hazardous air pollutant (also known as "NESHAP" or "MACT") compliance and enforcement, Title V permitting, Regional Haze and Best Available Retrofit Technology rulemakings and disputes; rulemaking and compliance matters relating to National Ambient Air Quality Standards, and various greenhouse gas rulemaking and compliance matters, including EPA methane regulation and Greenhouse Gas Reporting rules.

Jonathan also represents manufacturers of consumer products with regard to the use of the Agency's Energy Star trademark.


  • Manufacturers of off-highway vehicles and engines in multiple EPA and California compliance investigations and enforcement actions.
  • Major global automobile, engine and equipment companies and trade associations in a wide range of EPA, NHTSA and California regulatory matters, including defense of major enforcement actions alleging use of "defeat devices," negotiation of an agreement on greenhouse gas emissions standards, negotiation of major recall investigations, compliance matters under the EPA and ARB greenhouse gas rules, congressional inquiries regarding those rules, litigation challenging or assisting in defense of major agency rules, and regulatory questions and enforcement matters regarding labeling, onboard diagnostics, defect reporting, European greenhouse gas requirements, and federal fleet purchasing requirements.
  • Multiple chemical companies in conducting comprehensive air emissions compliance audits.
  • Truck Trailer Manufacturers Association in successful challenge to EPA and NHTSA greenhouse gas regulations applicability to trailers.
  • Major natural gas processor in defense of state enforcement proceeding regarding New Source Review and related air emissions requirements.
  • Renewable fuels trade association and manufacturer in rulemakings and litigation regarding EPA renewable fuels regulations, registration requirements, and related requirements.
  • Major gasoline companies in defense of EPA enforcement actions concerning volatility, sulfur, and benzene requirements for gasoline.
  • Battery recycling company in addressing various regulatory and enforcement issues related to air emissions.
  • U.S. chemical company in defense of U.S. EPA claims for New Source Review and Prevention of Significant Deterioration violations, defense of U.S. EPA claims for violations of hazardous air pollutant requirements, and assistance in air permitting, including for a major new plant with novel issues raised by emissions of greenhouse gases.
  • Refrigerator manufacturer and a ventilation fan manufacturer with regard to potential Energy Star disqualification.


Looking Ahead — Implementation of EPA’s New Methane Rule
Environmental Edge: Climate Change & Regulatory Insights
Tracking Greenhouse Gas Emissions and Climate Risks
Environmental, Social, Governance: The Professional's Guide to the Law and Practice of ESG
Chambers Global 2024 Ranks 35 Arnold & Porter Lawyers, 31 Practice Areas
Environmental, Social, Governance: The Professional's Guide to the Law and Practice of ESG
Environmental, Social, Governance: The Professional's Guide to the Law and Practice of ESG
Fuel Economy Proposal Emerges in Complex Regulatory Landscape


Chambers Global
Climate Change — Global Market Leaders (2021-2024)
Best Lawyers
Environmental Law — DC (2009-2024)
"Lawyer of the Year" Environmental Law — DC (2016, 2018)
The Legal 500 U.S.
"Leading Lawyers" Environment Regulatory (2023)
Environment: Regulatory (2017-2022)



  • J.D., Yale Law School, 1989
  • A.B., Dartmouth College, 1986, summa cum laude, Phi Beta Kappa


  • District of Columbia

Government & Military Service

  • Office of General Counsel, U.S. Environmental Protection Agency


  • U.S. Court of Appeals for the First Circuit, The Honorable Levin H. Campbell


  • Vice Chair, ABA Section on Environment Energy and Resources, Air Quality Committee (1994-2016)
  • Clean Air: Law, Policy and Practice Annual Advanced ALI-ABA Course of Study, co-sponsored by the Environmental Law Institute (ELI), Arnold & Porter LLP, Washington, DC (Co-Chair, 2007-2011)