William J. Walsh

William J. Walsh

Of Counsel

Washington, DC
Phone: 202.220.1424    Fax: 202.220.1665


"Great insight into federal environmental regulation." -- Chambers USA 2015 

William J. Walsh is of counsel in the Washington office of Pepper Hamilton LLP, where he heads that office’s Environment and Energy Practice Group. He also is a member of the firm’s Sustainability, CleanTech and Climate Change Team. Mr. Walsh provides a range of environmental counseling, compliance, permitting, transactional and litigation services (including defense of personal injury claims) to foreign and domestic clients of varying size across the spectrum of business and industry. His experience encompasses all major federal environmental statutes, such as the Clean Air Act, the Clean Water Act, Superfund, the Resource Conservation and Recovery Act, the Toxic Substances Control Act, and many state and local environmental laws. He has also assisted clients in matters involving foreign environmental laws. Often, his counseling involves innovative scientific, regulatory, legal and policy questions.

Mr. Walsh has written and spoken on a wide range of topics, including risk assessment, the toxicology of polychlorinated biphenyls (PCBs), EPA’s sediment cleanup initiative, the issues raised by EPA’s endocrine disrupter theory, choosing cleanup goals and technologies, the use of groundwater models in the regulatory system and toxic torts.

Before joining Pepper in 1986, Mr. Walsh served as section chief of the U.S. Environmental Protection Agency (EPA) Office of Enforcement and was lead EPA counsel on the precedent setting hazardous waste lawsuits brought against Occidental Chemical Corporation concerning the Love Canal and related landfills. He also worked in the Office of Water Enforcement.


  • J.D., George Washington University National Law Center , 1978, Elected to the Order of the Coif.
  • B.S., Physics, cum laude, Manhattan College, 1968

Bar Admissions

  • District of Columbia

Practice Areas