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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?

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Environmentalists contend that while the mercury may start out in the vats of old-line chlor-alkalai plants, it may well evaporate into the atmosphere, wafting out windows - or leak into the soil and water around these plants.

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"The EPA darn well better find the lost mercury from chlorine plants because people's health depends on it," says Linda Greer, a scientist with the NRDC. "But the larger issue is that there is no reason for these plants to continue consuming mercury to produce chlorine."

Indeed, most of the 43 chlor-alkalai manufacturing plants in the US today use advanced mercury-free manufacturing processes that are relatively clean. But nine US factories - and 53 older ones in Europe - still use older "mercury-cell" technology that requires huge quantities of mercury to do the same job, Oceana reports.

The mercury-cell process involves pumping salt brine through mercury vats, or "cells." Each cell can be more than 50 feet long and 5 feet wide and hold in the neighborhood of 8,000 pounds of mercury. An electric current flowing into the cell creates a reaction that produces chlorine and caustic soda, also called lye.

Even though most factories have shifted to nonmercury technologies, the Chlorine Institute does not support phasing out mercury's use. "There is no good reason to eliminate more US manufacturing jobs by closing plants that are operating safely and performing above and beyond all federal and local standards," writes Ms. Cullen.

It's not clear whether regulators will force a change. Despite growing pressure to clamp down on mercury emissions, "Clear Skies" legislation reintroduced last week in Congress is focused primarily on power plants.

Environmentalists hope, however, that modifications to another new federal rule, currently being reviewed by the EPA, will target lost mercury from chlor-alkalai plants. The original rule was delayed after the NRDC and Sierra Club sued the EPA, arguing it would not adequately deal with unaccounted-for mercury.

Meanwhile, Europe is moving ahead to phase out mercury in its chlor-alkalai plants by 2007. In 2000, the mercury-cell chlorine plants in the first 15 member states of the European Union reported using 104 tons - with 96 tons of that unaccounted for, Oceana reports.

With phaseout, however, arises a major problem over what to do with hundreds of tons of mercury inside these older plants.

In Maine, after the mercury-cell chlorine plant near Mr. Judd closed, the mercury was sold to a broker who planned to sell more than 100 tons of it abroad. An outcry by environmental groups brought a shipload of 20 tons, already bound for India, back to the US. Today, the bulk of the mercury sits in Wisconsin storage tanks, Maine environmentalists say.

"I lived next to that plant for 10 years without any idea there was that much mercury there," Judd says. "People would tell us it was a chlorine plant. But that's what you put in your pool, right, to clean up water? We all use chlorine in our washing machines, swimming pools, and everything else. It took us awhile to wake up."

Chlorine: from pipe to paper

Discovered in 1774, this greenish-yellow gas (after the Greek chloros, "greenish yellow") is so reactive that it appears on Earth only combined with other elements, especially sodium, to create salt. Among chlorine's many uses:

• Water purification. It's employed the world over to help purify drinking water and to clean swimming pools.

• Plastic: Polyvinylchloride or PVC pipe is the preferred conduit for sewage and water supply because it doesn't rust.

• Bleach: Besides the household variety, chlorine compounds are used to bleach pulp for paper.

• Poison gas: Fatal at high concentrations, chlorine became a weapon in World War I.

Sources: CRC Handbook of Chemistry and Physics; American Chemical Society; Environmental Literacy Council