Douglas McWilliams’ practice encompasses all areas of environmental counseling, with an emphasis on Clean Air Act (CAA) issues, enforcement and rule development. Douglas has particular experience in transportation, metals and energy sectors; helping manufacturers identify and resolve compliance issues; navigating certification and permitting requirements for vehicle manufacturers and upstream supply chain businesses (e.g., engines, metals, tires, coatings, etc.); influencing complex rulemaking to advance client interests; and advising on strategic business pursuits in this complex and changing environmental regulatory landscape. He also counsels clients on wastewater and hazardous waste issues related to manufacturing and project development. He provides environmental legal services in the context of a deep understanding of his clients’ businesses.

Douglas’ mobile source experience includes regulatory counseling and enforcement defense for non-road, marine and highway engine and vehicle manufacturers, with a focus on helping companies navigate complex state and federal standards. He conducts compliance assessments to identify issues and opportunities and, when needed, internal investigations into civil and criminal allegations. He helps manufacturers navigate disclosure obligations, warranty claims and recalls for environmental issues and emissions-related equipment. He defends manufacturers and resolves disputes in administrative, civil and criminal proceedings.

He also develops and implements rulemaking strategies to advance business interests and relieve regulatory burdens. This includes appellate-level advocacy for rule changes at the federal and state levels. Douglas recently provided oral arguments before the DC Circuit Court of Appeals on federal CAA rules governing hazardous air pollutant standards and ambient air quality issues. He works with companies to obtain complex permits and clear regulatory obstacles to their new business ventures and expansions.

Douglas brings decades of experience working with manufacturers, utilities and local governments on environmental issues. He gains knowledge through the rulemaking process that is particularly useful in helping his clients navigate compliance options and enforcement risks.

Douglas’ air experience began with his work as a permit engineer for one of Southern California’s air pollution control districts, where he processed air permit applications and implemented one of the first rules governing emission reduction credit banking and trading. He now advises clients in market-driven strategies for environmental compliance and innovative permitting solutions. In addition, Douglas led the effort to reform federal industrial boiler rules to eliminate obstacles to the use of process gases to displace fossil fuels in the generation of steam and electricity for industrial use.

Douglas has trial and appellate experience under the CAA and in the areas of hazardous waste litigation under the Comprehensive Environmental Response, Compensation and Liability Act (CERCLA) and related state law claims. He also serves as common counsel to PRP organizations and advises clients on strategies for brownfield disposition and redevelopment.

Douglas is a member of the Section of Environment, Energy, and Resources of the American Bar Association, the Ohio Bar Association and the Cleveland Metropolitan Bar Association. He has been listed in The Best Lawyers in America since 2006 and is listed in Ohio Super Lawyers. He is also recommended by Chambers USA as a Leading Lawyer for Business in the area of Environmental Law.

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  • Jointly representing truck and engine manufacturer in disclosure of audit findings and implementation of negotiated administrative remedy with the US Environmental Protection Agency (EPA) to address non-compliance.
  • Advising engine manufacturer regarding voluntary recall campaign for emission-related engine components in coordination with the EPA, California Air Resources Board and Environment Canada.
  • Conducting attorney-directed compliance assessment for manufacturer’s US coating operations and developing findings prioritization and implementation strategy for risk mitigation.
  • Implementing onsite audit of environmental compliance for mining and processing facilities in multiple states to develop uniform metrics for process risk management.
  • Engaging in due diligence of environmental compliance issues for buyer of iron and steel manufacturing facilities in multiple states, including South Carolina, Pennsylvania, Ohio, Indiana and Illinois.
  • Assisting municipal electric plant with US Department of Energy-funded battery storage project and related matters.
  • Representing specialty truck and vehicle manufacturer in the development of federal rules governing greenhouse gas emissions.
  • Negotiating consent decree with the EPA and the US Department of Justice (DOJ) to clean up solvents spilled on soils effecting groundwater adjacent to a river and managing implementation of clean up.
  • Reviewing and updating stormwater pollution prevention plan and related NPDES permit for discharges to surface water from airport operations.
  • Drafting the renewable energy credit transfer provisions for a power purchase agreement for a rooftop solar installation.
  • Conducting complex netting analyses to facilitate permitting new boilers burning process gases previously flared and other alternative and renewable fuel sources.
  • Developing consistent national environmental management systems for appliance manufacturer doing business in multiple jurisdictions, including South Carolina and California, consistent with international standards.
  • Negotiating resolution of federal and state enforcement allegations against iron foundry operations, including a consent decree with the EPA and the DOJ.
  • Briefing and arguing municipal petitioners’ challenge to the Industrial, Commercial and Institutional Boiler and Process Heater MACT rule before the DC Circuit Court.
  • Advising on New Source Review (NSR) and Prevention of Significant Deterioration (PSD) permitting for major modifications at major manufacturing facilities.
  • Challenging BART determinations before state and federal tribunals and obtaining a stay of the federal BART rule in the Eighth Circuit Court of Appeals for taconite processing facilities.


  • University of California, Berkeley, J.D., 1994
  • Oberlin College, B.A., 1984


  • Ohio, 1994


  • U.S. Ct. of App., District of Columbia Circuit
  • U.S. Ct. of App., Eighth Circuit
  • U.S. Ct. of App., Seventh Circuit
  • U.S. Ct. of App., Sixth Circuit
  • U.S. Dist. Ct., N. Dist. of Ohio
  • U.S. Dist. Ct., S. Dist. of Ohio

Memberships & Affiliations

  • Member, Section of Environment, Energy, and Resources of the American Bar Association
  • Member, Ohio Bar Association
  • Member, Cleveland Metropolitan Bar Association
  • Named by The Legal 500 US 2023 as a key lawyer for both Environment: Litigation and Environment: Regulatory
  • Recognized in The Best Lawyers in America 2023 and 2024 for Environmental Law
  • Listed in Who’s Who Legal: Environment 2022
  • Recognized in Chambers USA for Natural Resources & Environment in Ohio every year since 2006
  • Named by The Best Lawyers in America 2017 as Lawyer of the Year for Cleveland Environmental Law

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