TVA is investigating a spill at a gypsum pond at Widows Creek Fossil Plant in Stevenson, Ala. The spill was discovered before 6 a.m. on Friday.
TVA officials said water and gypsum from the gypsum pond drained into an adjacent settling pond after a cap dislodged from a 30-inch standpipe, which had at one time been used to drain water from the gypsum pond into the settling pond. When the cap dislodged, water and gypsum flowed into the settling pond, which filled to capacity and then overflowed.
The overflow stopped when the level in the gypsum pond dropped to the level of the standpipe.
Some material overflowed into Widows Creek, although most of the gypsum remained in the settling pond, officials said.
TVA said it notified appropriate federal and state authorities, as well as Stevenson, Scottsboro, and Huntsville utilities, to inform them of the incident. The closest municipal water system is in Stevenson, but the Stevenson system does not withdraw water directly from the Tennessee River, it was stated.
Booms are being installed in Widows Creek and the Tennessee River adjacent to the plant to contain the gypsum.
TVA is performing permanent repairs to the standpipe, officials said.
Gypsum ponds hold limestone spray from TVA’s scrubbers that clean sulfur dioxide (SO2) from coal-plant emissions. Gypsum contains calcium sulfate, which is commonly used in drywall, a commercially sold construction material.