The bill, which would have affected Olin Corp.'s Augusta plant and three others in the U.S., was screened by a Republican administration favorable to big business -- and never passed.
In January, however, the sponsor of that 2006 bill -- Barack Obama -- becomes president, and environmental groups hope to successfully resurrect the mercury issue.
"It can be brought up again very easily, and we believe it will be," said Jackie Savitz, senior campaign director at the environmental group Oceana, which has lobbied for years to bring an end to the use of toxic mercury in the chlorine industry.
More than 95 percent of U.S. chlorine plants have converted to mercury-free technology, she said. The remaining plants using mercury include Olin's Augusta plant and three other sites in Tennessee, West Virginia and Ohio.
Such plants make chlorine by pumping saltwater through a "cell" of mercury to create a chemical reaction. The process causes mercury to be released into the environment, where it can accumulate in fish and be passed along to humans.
Olin has invested in technology to reduce mercury emissions, and reported releasing 137.85 pounds in 2007, down almost 85 percent from the 834.5 pounds the plant released in 2005.
Ms. Savitz said supporters of the initial legislation are optimistic.
"The politics really got in the way before, but with the new reality of Sen. Obama in the White House, I think we have a very good chance of getting that bill through," she said.
Olin officials have said conversion to modern technology -- costing as much as $90 million -- is neither necessary nor financially feasible.
David Blair, Olin's Augusta plant manager, said the site remains in compliance with state and federal permits and has reduced mercury emissions by investing in better technology.
"Changing the existing technology at our facility would require tearing down and rebuilding the entire plant, potentially affecting hundreds of people in the region," he said, adding that converting to mercury-free technology is "simply not warranted."
He would not say what would happen if Congress does pass a law.
"We decline to speculate on legislation that may be proposed, including how such proposed legislation may impact our operations," Mr. Blair said.
Mercury is a persistent and potent neurotoxin that damages neurological development in children and cardiac health in adults, according to environmental groups, who contend companies can save money on electricity, waste disposal and environmental compliance by switching to modern technology.
Reach Rob Pavey at 868-1222, ext. 119, or firstname.lastname@example.org.