In question is the metal selenium, which is a byproduct of coal- and phosphate-mining, copper-smelting and agriculture. At low levels, selenium is an essential nutrient for healthy immune systems, but at higher levels it can be toxic, as scientists found at California’s Kesterson Wildlife Refuge in the 1980s. There, high levels of selenium from agricultural runoff killed and deformed thousands of waterbirds.
In 1998, the EPA ruled that levels of selenium in water could not exceed 5 parts per billion. But in March 2002, the EPA proposed a new standard that would be measured in fish tissue, rather than in water samples; the new standard would be a much higher 7.9 parts per million, levels that the agency admitted would kill one-fifth of all fish. "For some reason known only to them, their goal was 20 percent mortality," says Joseph Skorupa, a selenium expert with the U.S. Fish and Wildlife Service. "We wrote a letter saying this isn’t suitable under the Endangered Species Act."
Researchers then realized fish mortality would be even higher because the EPA had made a mathematical error: With concentrations of 7.9 ppm in their bodies, more than 60 percent of the fish would die.
But by early 2004, coal-mining companies were pressing the EPA to move ahead. In July, the EPA released another draft, still pushing the 7.9 standard.
According to Skorupa, before the EPA could finalize the rule in late August as planned, an article about the selenium standard appeared in the Sacramento (Calif.) Bee. After outcries from the public and politicians such as Sen. Dianne Feinstein, D-Calif., the EPA pulled back.
"We received some additional information that we wanted to take a look at and consider and review before we put out a final notice," says Cathy Milbourn, an EPA spokeswoman. She adds that the issue was "not driven by the election – it’s something that is still under internal review and when that review is complete, it will be out for public comment."