CHATTANOOGA, Tenn. (AP) -- An environmental group has renewed its call for an Olin Corp. chlorine plant to stop mercury pollution that is contaminating the Hiwassee River in eastern Tennessee.
Dianne Saenz, a spokeswoman for Washington-based Oceana, said a new study shows that Olin's plant at Charleston is the ''chief source of mercury contamination'' in the river.
It also describes the plant as ''the largest emitter of mercury to the air in all of Tennessee and the largest total mercury emitter of the four remaining mercury-based chlorine plants in the U.S.''
Plant manager Tom Tirabassi said in an e-mail statement that mercury air emissions have been reduced significantly and its use is careful and controlled.
Oceana representatives last year called on Olin to follow the lead of more than 100 other chlorine plants that have changed from a mercury-based process to nonpolluting technology.
Mercury is a neurotoxin that accumulates in fish. Ingesting mercury can cause nerve and brain damage to pregnant women, women of childbearing age and young children. Mercury also can lead to kidney damage in children.
The Oceana report shows the Tennessee Department of Environment and Conservation issued a new fish consumption warning for a 7-mile stretch of the river and determined it was no longer ''fishable'' due to mercury.
''The mercury levels in sediment upstream of Olin are low and below levels associated with harm, while those levels near Olin's pipes and downstream are so high (more than 100 times higher than average) that some sediment-dwelling organisms are predicted to die within 10 days of exposure to those toxic sediments,'' the report said.
Department spokeswoman Tisha Calabrese-Benton said Olin's five-year national pollutant discharge permit is up for renewal and the application is ''under review by the department at this time.''
She said the Environmental Protection Agency will also be involved in a review and controls that timetable.
''It is important to note that the Hiwassee River watershed is quite large, covering three states,'' Calabrese-Benton said in an e-mail statement. ''We don't think it's correct to say Olin is the only source of mercury in the watershed. A unified approach that considers all potential sources is needed.''
Oceana contends that even though changing to membrane-cell technology would reduce costs for the chlorine plants, the four that continue to use mercury are Olin's plants in Charleston and Augusta, Ga.; Ashta Chemicals in Ashtabula, Ohio and PPG Industries in Natrium, W. Va.
Chlorine is used in swimming pools, plastic tents and paper towels and is produced in a chemical reaction that involves pumping a saltwater solution through a vat of mercury, or a mercury cell.
Tirabassi said the plant reduced mercury air emissions ''by over 60 percent in 2007, over and above our previous reductions.''
''Our use of mercury is careful and controlled,'' he said. ''We discharge less than one-third of what the government allows for water and meet all other regulations as well. In fact, we reduced mercury emissions 87 percent in the past 20 years. During an eight-year period, we spent $54 million to update the Charleston plant, including $2.6 million over the last two years to meet stricter government mercury regulations.''
Tirabasi's statement said there are about 460 employees at the Charleston plant, a total of about 900 related jobs and ''our products are vital to public health.''
He said changing to non-mercury technology would require the company to ''dismantle most of the plant and rebuild it, interrupting production and impacting the lives of people in this area.''
A 2005 EPA regulation called for a 70-percent cut in mercury releases over the next decade. Congressional legislation that would put deadlines on the use of mercury in chlorine or caustic soda manufacturing has languished.