Areas of Practice
  • Yale Law School, J.D., 1980
  • University of North Carolina, Chapel Hill, B.A., 1977
Judicial Clerkships
  • Hon. Robert R. Merhige, Jr., US District Court for the Eastern District of Virginia, 1981-1982
Bar & Court Admissions
  • District of Columbia

William T. Hassler

1330 Connecticut Avenue, NW
Washington DC 20036
TEL: +1 202 429 6469
FAX: +1 202 429 3902

William T. Hassler is a partner in Steptoe’s Washington office, where his practice has encompassed a broad range of criminal and civil cases.  Prior to joining the firm, Mr. Hassler served as a prosecutor for the Office of Independent Counsel investigating the Iran/Contra affair, and in the Environmental Crimes Section of the US Department of Justice.  He is a former Special Assistant to the Director of the Federal Bureau of Investigation (FBI).

Civil Litigation

Mr. Hassler’s practice has included a variety of civil disputes involving environmental matters, including enforcement issues relating to pipeline spills.  His experience includes the trial of CERCLA liability issues, as well as defense of civil environmental enforcement actions, criminal environmental enforcement matters, and criminal and civil claims relating to alleged corporate misconduct, including the defense of Tyco’s former general counsel. 

White-Collar Criminal Defense

Mr. Hassler has represented numerous companies and individuals subject to criminal investigation.  He has handled cases involving complex environmental matters, charges of healthcare fraud, other corporate misconduct, the regulation of medical devices, and the representation of witnesses subject to investigation by Congressional committees.

Representative Matters

Recent Trial Experience (selected examples):

  • Represented pipeline company in connection with resolution of claims relating to major inland oil spill
  • Represented William Facteau in US v. Facteau (D. Mass. 2016) (jury trial that resulted in defendant’s acquittal of multiple felony charges)
  • Represented plaintiff American International Surplus Lines, Inc. (AISLIC) in AISLIC v. United States (C.D. Cal) (March 2012) (bench trial; damages phase of prior successful liability trial brought under the Comprehensive Environmental Response Liability Act)
  • Represented defendant Lauren Stevens in United States v. Stevens, (D. Md.) (2011) (jury trial; charges against client dismissed by judge at close of government’s case)
  • Represented AISLIC in first phase of AISLIC v. United States (C.D. Cal) (2010) (bench trial involving CERCLA claims that resulted in finding of liability against United States)
  • Represented Mark Belnick, former general counsel of Tyco, in connection with multiple actions, including In re Tyco International Ltd., Securities, Derivative, & ERISA Litigation, (Multidistrict Litigation heard in D. N. H. 2002 to 2007) (class action litigation, resolved by settlement)
  • Represented Lexington Insurance Company in Alcoa v. Accident & Cas. Ins. Co. (Super. Ct. Wash. 2002-03) and UTC v. American Home Ins. Co. (D.Conn. 2001-02) (large, multi-site litigations regarding insurance claims for environmental damages; resolved by settlement)
  • Represented C&A Carbone and National Solid Waste Management Association in Atlantic Coast Demolition & Recycling, Inc., v. Board of Chosen Freeholders of Atlantic County (D.N.J.) (bench trial and injunctive action) and in Atlantic Coast Demolition & Recycling, Inc., v. Board of Chosen Freeholders of Atlantic County, 112 F.3d 652 (3rd Cir. 1997) (invalidating statewide, New Jersey solid waste system as inconsistent with the Commerce Clause in light of firm’s representation of same client in C&A Carbone v. Town of Clarkson, 511 U.S. 383 (1994)).


  • Legal 500 US, Litigation: White-Collar Criminal Defense, 2016
  • Washington, DC Super Lawyers, Criminal Defense: White Collar, 2016-2017

Select News & Events

Selected Publications

  • Congressional Oversight of Federal Environmental Prosecutions; 24 Envir'tl Law Rev. 10074
    February 1994
  • Co-Author, Coal and the Clean Air Act ; Yale Press

Professional Affiliations

  • American Bar Association, Litigation Section; Section of Natural Resources, Energy and Environmental Law