In a cloud of uncertainty, the Idaho Board of Environmental Quality backed off its efforts to strengthen rules to regulate industries that emit mercury into the air.

The board voted down a motion Feb. 12 that would have asked industries to voluntarily install the best available technology for removing mercury from their smokestacks under a well-coordinated lobbying effort by the Idaho Association of Industry and Commerce, the Idaho Council on Industry and Environment and Monsanto Corp., whose P4 phosphate plant in Caribou County in Southeast Idaho is the state's largest mercury source.

The industry groups rolled over the Idaho Conservation League, which had petitioned to get the board to regulate mercury in the state in an effort to combat the pollutant that accumulates in fish and can cause brain damage and learning disabilities in babies and young children. The ICL and its program manager Justin Hayes had successfully led the effort to get the state of Nevada to require gold mines in that neighboring state to restrict much higher mercury emissions after studies showed that winds were carrying the neurotoxin into Idaho and that at least one reservoir, Salmon Falls Creek south of Twin Falls, had high mercury levels.

Hayes had convinced federal and Nevada officials that their voluntary program was allowing miners to pump thousands of pounds of mercury into the air. Today, Nevada has one of the strongest mercury abatement programs for mines in the world.

But the case for regulation was not as clear in Idaho, and the industry groups were far more sophisticated about exploiting the uncertainty in the science.

They hired one of the world's top mercury pollution experts, Steve Lindberg, a retired environmental chemist from Oak Ridge National Laboratory in Tennessee. He has helped develop mercury rules for states and the EPA and has worked on both sides of the issue throughout his career.

He said in a report and a presentation to the board that the science linking a source like the P4 plant to high mercury levels in fish in nearby reservoirs was not yet clear enough. He raised questions about whether atmospheric mercury pollution was as serious a problem in the American West as it is in the East, where there is more rain and more wet deposition of the pollutant.

And he even raised doubts, based on yet unpublished research, that the high mercury levels in Salmon Falls Creek Reservoir were linked to the massive mercury pollution that had come from the mines in Nevada before they were regulated.

Previously, the board had heard from U.S. Environmental Protection Agency experts that models showed a source like the P4 plant could be linked to the elevated mercury levels in nearby lakes. But even Hayes acknowledged that science was not yet clear.

He urged the board to put in place regulations that would limit mercury pollution, especially in new sources. The current regulations are aimed at keeping mercury inhalation by workers and people near a plant low. But they allow a company to emit huge levels of mercury, as much as 100,000 pounds, which all agree would be harmful to the state's aquatic systems.

But the P4's emissions, at 600-700 pounds, are far below such numbers. They still are higher than coal-fired power plants. Its officials say they have erred on the high side of their estimates because EPA reporting requirements have high penalties for reporting below actual emissions.

And Monsanto says its scrubbers for other pollutants have reduced mercury emissions. It proposed that the state use water quality regulations to control mercury levels in lakes instead of air regulations.

"This confusion and uncertainty makes it hard for us to make rules," said Nick Purdy, a board member from Picabo.

So the state's flawed rules - even by Lindberg's opinion - stay in place for now.

Rocky Barker: 377-6484