"We have people working into their early 60s without any problems," he said. "We're seeing quite a bit of retirees at that age leading the plant. Those are celebrations on our part."Quinn Smith, a 28-year-old who lives in the Navajo community of Shiprock, N.M., recalled stories from elders about the land being more lush before the power plants were built and the air more clear. Mercury has been linked to cancer, heart disease and premature death. "Even right now, I'm looking out and there's a yellow mist," he said. Farmington Mayor Tommy Roberts, whose New Mexico city sits in the shadow of the Four Corners and San Juan plants, said the challenge for city leaders with any EPA regulations has been to assess whether the benefits associated with them are real. "I say as frequently as I can that we want clean water, we want clean air but we also want a healthy economy and the challenge is to find an appropriate balance," Roberts said. Aside from oil and natural gas development, Farmington's economy depends on the hundreds of jobs and millions of dollars in taxes generated by the power plants, which straddle the San Juan River, and their associated mines. Michael Capps, a 62-year-old Farmington resident who helped build Four Corners and the San Juan plants, doesn't buy the argument that pollution controls can help the aging plants. "What people are not realizing is both plants are worn out," he said. "There's nothing you can do; they cannot be fixed. They need to be replaced. Period. That would solve a whole lot of problems." ___ Associated Press writer Susan Montoya Bryan reported from Albuquerque, N.M.