BOISE, Idaho (AP) -- Idaho water quality regulators must go back to the drawing board after the federal government this week rejected a 2-year-old rule that allowed some new pollution to be discharged into the state's prized waterways without review.
In 2011, the U.S. Environmental Protection Agency approved an Idaho Department of Environmental Quality rule exempting activities such as mining from review, provided their accompanying water pollution fell below a certain threshold.
The Greater Yellowstone Coalition and Earthjustice sued, saying that was too lenient, especially in instances where pollution builds up in aquatic ecosystems. They worried, among other things, that toxic chemicals that persist in the environment and accumulate in food chains could pose health risks.
In April, the EPA agreed in U.S. District Court in Pocatello to reconsider whether Idaho could exempt from review certain polluting activities on rivers and lakes that had been designated under the Clean Water Act as "Tier 2" waters — in other words, those whose water quality is so good it exceeds levels necessary to support fish, shellfish and wildlife, as well as recreation.
With Tuesday's decision, the agency has now concluded DEQ's exemption went too far and gave the state agency several options to remedy the situation, including simply throwing out the exemption altogether.
"The provision could require Idaho to deem insignificant and, therefore, exempt from Tier 2 review, certain proposed activities or discharges involving bioaccumulative pollutants even though such activities or discharges may cause significant degradation," wrote Daniel Opalski, director of the EPA's Office of Water and Watersheds, on why his federal agency reversed course.
Barry Burnell, head of the DEQ's water quality office in Boise, said his agency will consider each of the options proposed by federal regulators. He said it's difficult to measure the impact the reversal will have across the state until his agency decides how to respond.
The EPA said Idaho DEQ has several options, now that the rule is no longer in effect.
It could simply delete the exemption and require all proposed polluting activities be reviewed; it could revise Idaho law with respect to how such exemptions apply to pollutants that could build up in the food chain; or it could revise the law to make exemptions possible, but only on a case-by-case basis.
"The state is obligated to revise the anti-degradation rule ... or we face the EPA making a rule for us," Burnell said. "We're going to prepare to undertake rule-making on this."
Waters where pollution could have been allowed without review under Idaho law included the Clearwater, Selway, Bear, Lochsa, Kootenai, Coeur d'Alene, Pahsimeroi and Boise rivers, among numerous others prized by recreationalists for fish and other qualities.
These rivers have been deemed able to continue to support fish, shellfish, wildlife and recreation even if a small amount of pollution is absorbed, subject to review.
Here's where Idaho's exemption came in: Two years ago, state regulators decided polluting activities didn't need to undergo formal review, if they consumed less than 10 percent of the water body's ability to accommodate pollution.
Environmental groups lauded Tuesday's announcement rejecting this exemption as a big victory.
"EPA's decision protects Idaho's most pristine water bodies against a 'death by a thousand cuts' from toxic chemicals that can accumulate to create a big pollution problem," Earthjustice attorney Laura Beaton said. "Going forward, no one may pollute the state's cleanest waters without an in-depth review — and that's just common sense, which is desperately needed if we want our waters to be clean and safe."