Her arrival at Earthjustice in July 2008 marked a return to the practice of environmental law, where she spent the first decade of her legal career. As an attorney at the law firms Berle, Kass & Case and Arnold & Porter, she concentrated in cases involving environmental impact review, historic preservation, and hazardous waste issues. She was lead counsel at the U.S. Supreme Court for the county intervenors in New York v. United States, 505 U.S. 144 (1992) (overturning portions of the Low Level Radioactive Waste Policy Amendments Act). While in private practice, she also co-authored with Michael B. Gerrard the environmental law column of the New York Law Journal.