William Duffy’s practice spans a broad range of environmental and natural resources issues. Since 1991, he has been a significant provider of legal services for Atlantic Richfield Company in the Rocky Mountain region on matters related to CERCLA and state law cleanups, including the Clark Fork River NPL sites in Montana. A substantial portion of his work has been related to natural resource damages claims asserted by state and Native American tribal trustees. His practice focus is litigation defense, including natural resource damages and CERCLA contributions claims, and negotiation of consent decrees and administrative orders, and other administrative proceedings.

In addition, Mr. Duffy has represented clients in administrative proceedings before the Colorado Water Quality Control Commission and the Air Quality Control Commission. His litigation experience includes numerous trials before state and federal district courts, and Water Court in Colorado. He has also lectured on issues related to negotiation of CERCLA administrative orders and performance of remedial action.

Prior to joining the firm in 1999, he was a director at the law firm of Parcel Mauro, P.C. He began his legal career at Kelly, Stansfield and O’Donnell. Before beginning his legal career, Mr. Duffy worked as a hydrogeologist managing CERCLA and RCRA technical investigations for industrial clients.  Mr. Duffy is listed in Who’s Who in America, Who’s Who in American Law, the 2006 edition of The Best Lawyers in America®, and is active in the Natural Resources and Energy and Environmental Law Sections of the American Bar Association.