The Minnesota Pollution Control Agency approved an air pollution permit Tuesday for a major expansion at U.S. Steel's taconite plant in Keewatin on the Iron Range.
The company is venturing into new territory as it promises to control the increased mercury emissions that will come from new production. The permit does not include a specific limit on mercury; rather, the MPCA will wait to see how well the company's controls work before it sets a restriction.
Environmental groups are dismayed. They say the permit includes no guarantees that mercury pollution will be reduced.
Taconite processing is the second-largest source of mercury pollution in Minnesota, after electric power plants.
Mercury is a neurotoxin that can build up in fish tissue, and it can cause nerve damage and developmental problems in humans. That's why the state advises people to limit their fish consumption from Minnesota lakes.
U.S. Steel officials say they're going to test a system that captures mercury as it leaves the stacks. It's a system that's used in power plants.
U.S. Steel environmental director Chrissy Bartovich says activated carbon injection will capture mercury, but the company has to change the scrubbers on its stacks, from wet scrubbers to dry.
"We know for our facilities that this is going to work. That's what we're going with, a known technology," said Bartovich. "Activated carbon was something we had problems with in the past, because it's not compatible with wet systems. That's why we decided to go with the dry controls."
The air permit directs U.S. Steel to test the activated carbon system, shoot for an 80 percent reduction in mercury emissions and report back to the MPCA. Then, the agency will set a limit on the mercury emissions.
That's a problem for environmental groups, which would rather see a numerical limit in the permit to begin with.
"This is a pretty big departure from what would normally be required in a permit -- that is enforceable conditions that both the MPCA and other citizen groups that are concerned about the environment can go to court to enforce," said Kevin Reuther, an attorney with the Minnesota Center for Environmental Advocacy.
The MPCA says it's confident the process will work. Agency engineer Anne Jackson says once the bugs are worked out, she hopes the company can reduce mercury emissions by even more than 80 percent.
"It's a push to make sure you look at 80 percent, and they'll probably be able to do better than that," she said. "If that's the case, we'll have accomplished that much more in terms of reducing emissions overall."
Environmental groups are also frustrated because they say the MPCA is allowing U.S. Steel to bypass the state's plan for mercury pollution reduction. Paula Maccabee, an attorney with Water Legacy, says the state mercury plan requires U.S. Steel to find ways to reduce mercury emissions in other parts of its operation before it can increase emissions with the expansion.
"What the board is asking is, 'isn't it required that when you put new mercury in the air, you offset it pound-for-pound in addition to what's already required by the mercury implementation plan?' And the answer is yes," said Maccabee.
But the citizen's board of the MPCA voted unanimously to approve the permit. That vote indicates the board members trust that U.S. Steel's foray into mercury reduction will be successful enough to prompt other companies to adopt the same technologies.
The federal government will have its say on the permit over the next month. U.S. Steel will be back at the MPCA in a few months to apply for a water permit. The company hopes to start construction on its $300 million project late next year.