Joan Mulhern, 51, a forceful advocate for the environment who lobbied Congress and often rallied public support to sway lawmakers to her cause, died Dec. 18 of liver disease at MedStar Georgetown University Hospital in Washington.
Her death was relayed by a sister, Marie Mulhern.
Ms. Mulhern had been the senior legislative counsel for Earthjustice, a nonprofit environmental law firm, since 1999.
She fought repeated attempts by Congress to limit the scope of the Clean Water Act and battled coal companies and government officials over mountaintop-removal coal mining, in which mountains are blasted away to create strip mines.
"Joan did what Joan does best, and that was to loose the dogs of war," Martin Hayden, her former boss at Earthjustice, said.