Aaron represents clients in major environmental litigation and regulatory matters across the country, including nearly every significant proceeding involving the Environmental Protection Agency’s Regional Haze Program. His clients rely on his thorough legal analysis and strategic thinking to solve problems and guide their short-term decision-making and long-term planning.

Clients turn to Aaron when they face significant Clean Air Act regulatory matters. He has helped to resolve these matters before EPA, at the White House, and through his extensive litigation experience before the federal courts. Aaron’s previous roles as a legal advisor to the US Congress and as a lawyer for the White House help him provide insight and practical advice when counseling clients ranging from utilities to major corporations and trade associations in the energy, mining and transportation industries.

As a leader of the firm’s visibility practice, Aaron has been called upon to testify before the US House of Representatives. Aaron has also litigated significant visibility rules before numerous federal courts of appeals, arguing most recently before the Ninth Circuit. 

Aaron’s climate change work has involved every significant EPA rulemaking action since the US Supreme Court’s decision in Massachusetts v. EPA. He has, for instance, helped clients develop their responses and find creative solutions in response to EPA’s Endangerment Finding, its mobile source rules, and the Clean Power Plan for existing electric generating facilities.

Aaron’s practice extends to a number of other areas, including environmental permitting on Tribal lands, litigation in the DC Circuit over fuel regulation, and new source performance standards (NSPS) and hazardous air pollutant (HAP) regulations. Most significantly, he is integral to the firm’s national ambient air quality standards (NAAQS) practice, and has led successful efforts before the DC Circuit and the White House to protect clients from new, unprecedented standards.

Aaron is admitted to practice before the US Supreme Court and the US Courts of Appeals for the Third, Fourth, Fifth, Sixth, Eighth, Ninth, Tenth, and DC Circuits. He is also admitted to the US District Court for the District of Columbia.  

Relevant Experience

  • Advises clients on preparation for the Regional Haze Program’s second implementation period.
  • Represents industry in DC Circuit litigation supporting EPA’s rule allowing compliance with the Cross-State Air Pollution Rule to satisfy regional haze requirements.
  • Represented four western utilities in major challenges to EPA’s visibility rules in the Ninth and Tenth Circuit courts.
  • Led industry efforts challenging the establishment of new secondary NAAQS for nitrogen and sulfur oxides, particulate matter and ozone.
  • Represented trade associations in preparing comments on EPA’s proposed Federal Plan and Model Trading Rule to implement the Clean Power Plan.
  • Helped to guide interagency regulation of genetically modified organisms as part of the White House Ag-Biotech Working Group.
  • Represented the White House Office of Science and Technology Policy (OSTP) in regulatory review meetings and meetings of the Committee for Foreign Investment in the United States (CFIUS).
  • Advised members and committees of Congress on development of the Energy Policy Act of 2005 and drafted key reports on liquefied natural gas (LNG) regulation, public lands policy, military base closure and property redevelopment (BRAC), and offshore and onshore oil, gas, and renewables development.

Awards & Recognition

  • 2017 Chambers USA Environment Law Firm of the Year
  • Listed for Environment: Litigation, Legal 500 United States, 2016
  • Named among Rising Stars for Environmental Law, Law360, 2016
  • Selected as a Top Litigator Under 40, Benchmark Litigation, 2017