Timothy K. Webster

Tim Webster is a co-leader of the Sidley Austin’s Environmental, Health, and Safety practice. He joined the firm’s Washington, D.C. office from the U.S. Department of Justice where he served as a Trial Attorney in the Environmental Enforcement Section. His practice includes both civil and criminal environmental enforcement defense, as well as challenges to government actions, internal investigations, and regulatory advocacy and compliance counseling. Tim has handled a wide variety of civil and criminal cases under statutes such as the Clean Air Act (including stationary sources, mobile sources, greenhouse gases, and stratospheric ozone, and the Risk Management Program), the Clean Water Act (including oil spills and permit violations), CERCLA (including cost recovery, contribution, and release reporting), the Federal Insecticide, Fungicide, and Rodenticide Act (misapplication and misbranding), as well as “toxic tort” and other matters.

Tim served as the 44th President of the District of Columbia Bar, a position he held while remaining a partner at the firm. This “unified” bar is the mandatory licensing authority for all District of Columbia lawyers and has over 100,000 members and about 150 employees. He also led the D.C. Bar Pro Bono Center, an affiliated 501(c)(3) entity that recruits, trains, and mobilizes volunteer attorneys to take pro bono cases serving individuals living in poverty. In addition, Timothy served as outside General Counsel of the D.C. Bar from 2004–2010, advising on business matters and defending the Bar and its employees in litigation.

While at the University of Virginia School of Law, Tim served as editor-in-chief of the Virginia Environmental Law Journal. After clerking, he joined the DOJ, where he litigated complex civil enforcement cases brought under a variety of federal environmental statutes, including CERCLA, the Clean Air Act, the Clean Water Act, and the Oil Pollution Act, among others.

Tim is listed in Who’s Who Legal, Chambers USA, and The Best Lawyers in America®. He is ranked by Chambers USA for Environment in District of Columbia (2009–2025) and is recognized as a “Litigation Star” in the Environmental category by Benchmark Litigation (2016–2025). He is also featured by Washingtonian Magazine among its 2024 “Top Lawyers” list, named by Lawdragon for “Green 500: Leaders in Environmental Law” (2023–2025). Tim was recognized by Best Lawyers as “Lawyer of the Year” for Environmental Law (2023, 2026) and he was ranked by Best Lawyers in America® for Environmental Law (2009–2026) and Litigation-Environmental (2011–2026).