Chlorine dilemma: clean pool, dirty air
Old factories emit more mercury than do power plants. Even more of the toxin is 'lost.' But who's paying attention?
A few years ago, when his state's legislators were debating a ban on mercury thermometers, Richard Judd would have gladly pointed them to a much bigger threat. Down the road from his home in Orrington, Maine, sat 260,000 pounds of the potent toxin in corroding vats at an aging chlorine plant.Skip to next paragraph
Subscribe Today to the Monitor
"You could look out over what was really a lake of mercury almost the size of a basketball court," he recalls of a tour he once took of the plant. "I just could not have imagined that much mercury in one spot. It's incredible when you know that one teaspoonful can contaminate a small lake."
For those trying to highlight the link between mercury pollution and the industry that makes the basic ingredient for everything from household bleach to paper, such disregard seems typical. While public attention focuses mostly on coal-fired power plants spewing mercury into the air, nine old-line chlorine plants in the United States are also leaking an equally large amount, environmentalists say.
Or at least, they may be. On top of the 5 to 7.7 tons officially "emitted" into the environment, according to various estimates, far more tons of mercury mysteriously disappear every year during chlorine manufacturing. Older plants use mercury to create chlorine. "A lot of people just don't know there's this other source of mercury out there," says Dawn Winalski, pollution-projects manager for Oceana, a Washington environmental group that released a scathing report about the chlorine industry's mercury problems last week.
The 13 million to 14 million tons of chlorine produced in the US annually is used to purify water, bleach paper, and make myriad products: from car dashboards to bulletproof vests.
Although the industry has significantly reduced the amount of unaccounted-for mercury, no one knows for sure where it's located. In 2000, for instance, these chlorine plants reported 79 tons of mercury consumed, according to federal and industry data cited in the report. Fourteen of those tons were emitted or released into the environment; the rest - 65 tons - was officially classified as "unaccounted for" by the US Environmental Protection Agency (EPA).
That's an amount that shocks environmentalists because, by contrast, the nation's 497 mercury-emitting power plants sent 49 tons of the toxin into the air that year, Oceana reports.
"Sixty-five tons of mercury is a lot," says Jon Devine, a lawyer for the Natural Resources Defense Council (NRDC). "If a significant amount of this stuff is going out into the atmosphere, then these plants could rival power plants in terms of their contribution to mercury emissions in the US."
Chlorine industry officials argue that most of the mercury probably stays on the factory site trapped inside equipment and factory pipes.
"The chlorine industry can account for 99 percent of our total mercury inventory - but we realize that's not good enough," Tracy Cullen, a spokeswoman for the Chlorine Institute in Arlington, Va., writes in an e-mail. "We're fully committed to 100 percent accountability. And we're now working with EPA on new, more advanced methods for monitoring fugitive air emissions."
The best information so far indicates that unaccounted-for mercury is not being leaked into the air, the EPA says. Also, the industry's mercury consumption has fallen from an annual average of about 160 tons in the early 1990s to 30 tons in 2002, an 81 percent drop.
Even so, what happened to the missing mercury is a mystery. "The fate of all the mercury consumed at mercury cell chlor-alkalai plants remains somewhat of an enigma," the EPA declared in 2003 in the Federal Register.
"We agreed to conduct a detailed study to help us account for the mercury," says Cynthia Bergman, an EPA spokeswoman in an e-mail. "The unaccounted-for mercury from mercury cell chlor-alkalai plants is a very important issue to the agency."