Cathy Behr says she won"t forget the smell that nearly killed her. An emergency-room nurse in Durango, Colo."s Mercy Regional Medical Center, Behr was working the April 17 day shift when Clinton Marshall arrived complaining of nausea and headaches. An employee at an energy-services company, Weatherford International, Marshall, according to Behr, said that he was caught in a "fracturing-fluid" spill. [Fracturing chemicals are routinely used on oil and gas wells where they are pumped deep into the ground to crack rock seams and increase production.] The chemical stench coming off Marshall"s boots was buckling, says Behr. Mercy officials took no chances. They evacuated and locked down the ER, and its staff was instructed to don protective masks and gowns. But by the time those precautions were enacted, Behr had been nursing Marshall for 10 minutes--unprotected. "I honestly thought the response was a little overkill, but good practice," says Behr, 54, a 20-year veteran at Mercy.

A few days later, Behr"s skin turned yellow. She began vomiting and retaining fluid. Her husband rushed her to Mercy where Behr was admitted to the ICU with a swollen liver, erratic blood counts and lungs filling with fluid. "I couldn"t breath," she recalls. "I was drowning from the inside out." The diagnosis: chemical poisoning. The makers of the suspected chemical, Weatherford, tell NEWSWEEK that they aren"t sure if their brand of fracking fluid can be blamed for her illness.

Throughout the Rocky Mountain states, Behr"s run-in with fracturing fluid is getting a lot of attention and exacerbating already frayed nerves. After nearly eight years of some of the most intense oil and gas development ever recorded in the American West, concerns over the environmental and health impacts are bubbling over. On Tuesday, Colorado"s top oil and gas regulatory authority—the Colorado Oil and Gas Conservation Commission (COGCC)—endorsed a sweeping set of rules that environmentalists call long overdue; industry warns of dire economic impacts.