Mercury is a potent neurotoxin that damages the brain and nervous system. It's particularly detrimental to developing fetuses, which are often exposed to mercury when their mothers eat contaminated fish.
All Minnesota rivers and lakes have advisories that warn pregnant and nursing mothers and children to limit their fish intake. But environmental groups have long argued that the warnings are not enough. They've been calling on the state for years to do more about mercury.
Most of the mercury that's deposited into Minnesota waterways gets carried here by the wind. Much of that mercury comes from power plants scattered throughout the U.S. and world that emit mercury as a byproduct of burning coal.
Minnesota power companies contribute about 10 percent of the state's mercury pollution.
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That's not a lot in the big scheme of things. But David Thornton, Assistant Commissioner of the Minnesota Pollution Control Agency, says it's a problem the state must tackle.
"If we're going to try to get other states and other countries to reduce their mercury emissions, we need to set a good example," Thornton says.
Federal law already requires mercury emissions reductions. Thornton says Minnesota can do better.
"We think that the EPA rule just isn't quite good enough, actually. It doesn't get large enough emissions reductions, and it takes too long to do it," Thornton says.
In February, Gov. Pawlenty announced that he wanted state lawmakers to pass a bill requiring faster, more substantial mercury emissions reductions at the state's two largest coal-fired power plants.
That move surprised and pleased many environmentalists, among them the Clean Water Action Alliance of Minnesota's Erin Jordahl-Redlin.
"We thought, wow, if the governor is supporting this legislation we might actually get somewhere this year," Jordahl-Redlin says.
The governor's plan calls for a 90 percent reduction in mercury emissions at Xcel Energy's Sherco plant near Becker, and at Minnesota Power's Clay Boswell plant near Grand Rapids, by 2013. These two power plants produce the largest percentage of emissions coming from Minnesota facilities.
A Senate committee quickly approved a version of the bill that went even further. It added power plants in Burnsville and Stillwater, and moved up the compliance date to 2011.
Environmental groups and their lobbyists were dismayed when the House weakened the governor's proposal by pushing the compliance date out to 2015. Jordahl-Redlin says the House bill is barely stronger than the federal government's plan, which takes effect in 2018.
From our perspective, it's unconscionable to wait when you've got the technology.
"The main problem with the bill right now is that those coal plants are just given more time to pollute mercury, and it also includes a lot of outs for the coal plants. So if they can't get to 90 percent reductions, there's not a firm requirement that they ever get to 90 percent," she says.
Jordahl-Redlin blames the weaker bill on the effectiveness of the power company lobby.
One of those lobbyists is Margaret Hodnik with Minnesota Power. She says her company prefers the House bill, because it gives utilities more time to prepare for complicated and costly retrofitting projects.
Hodnik says Minnesota Power is looking out for its customers' best interests. She says about half of the utility's revenue comes from mining and paper companies.
"Those customers will pay for the largest proportion of anything that we do. And it's in our interest, and I think in the interest of the state for those industries that are globally competitive, to have time to adjust to these cost impacts," Hodnik says.
Hodnik says Minnesota Power has already come up with its own plans to reduce mercury at several of its plants. She says those plans require a slower retrofitting schedule, that staggers the projects over several years.
Xcel Energy lobbyist Rick Evans says his company also prefers the longer timeline in the House legislation. He says mercury emissions technology isn't good enough yet, especially for coal-fired units with wet scrubbers.
Wet scrubbers are air pollution control devices that use a liquid spray to capture pollutants from the air stream before they leave the smokestack.
"Nobody knows how to do mercury emission reductions, especially at a level of 90 percent on a wet-scrubbed unit. We think that technology is being developed, and we think it will develop in coming years," says Evans. "But we want to make sure that this legislation gives us the flexibility, and the time that we need to apply that technology as it comes on line."
Evans says if utilities buy the pollution control equipment currently on the market, they will only solve part of the mercury problem.
Bill Grant with the Izaak Walton League says delay is not the best route.
"From our perspective, it's unconscionable to wait when you've got the technology," Grant says.
He says if Minnesota passes a law requiring better mercury emissions equipment, inventors will find a way to develop the technology faster. "Even if you can't initially get all the way to the 90 percent goal, you know, let's get going and install the technology that's the best available today, and attempt to optimize that where we can," says Grant, "and take another five years from now to see whether or not the technology has advanced to allow us to achieve the 90 percent goal."
Despite Grant's concerns about the House mercury proposal, he believes it is still possible to resolve the differences between it and the Senate's bill. He says returning to the governor's original proposal might be a good approach.
But Clean Water Action's Erin Jordahl-Redlin is somewhat less optimistic. She views the weaker emissions bill in the Republican-controlled House as a sign that Gov. Pawlenty is not pushing his mercury reduction plan forcefully enough with members of his own party. She's concerned that Pawlenty might not object to the House bill.
"For me this really sent mixed messages," she says. "Is mercury reduction a priority of the governor's? Where's the leadership?"
The governor's spokesman Brian McClung says the governor's priorities on mercury reduction are clear.
"The governor has led on this. He stepped forward before the legislative session in February," McClung says.
McClung thinks it's likely that Senate and House lawmakers will ultimately return to the governor's original proposal as they try to work out their differences.
"We think, at the end of this process that the governor's proposal is a strong, solid step forward, and it's a consensus package that we're hopeful both the House and the Senate can agree with," McClung says.
There's no guarantee the governor's bill -- or any of the other mercury proposals -- will pass. But many of those involved say with a month and a half to go in the session, there's still enough time to salvage some form of a mercury emissions reduction bill.