LARGO — Old cleaning solvents are polluting the groundwater under Progress Energy's operations center next to Walsingham Park near Largo, and over the years the polluted groundwater has spread beneath the Pinellas County park, too.
Now, 14 years after the pollution was discovered, the utility has gotten a green light from the state Department of Environmental Protection for a plan to clean up the mess before it spreads to the Walsingham Reservoir.
The plan calls for pumping in a strain of bacteria specifically chosen because they will gobble up the pollution, leaving behind harmless byproducts like carbon dioxide, Progress Energy spokeswoman Suzanne Grant said Friday. The work is scheduled to begin next month, she said.
Because the pollution is all underground, "there has been no human contact with the solvents," Grant said. About 70 people work at the building at 12600 Walsingham Road.
The cleanup has been a long time coming. Workers discovered the pollution in 1997 while testing around the utility's property for any signs of leaking from underground gasoline tanks. Instead of chemicals related to gasoline, they found a plume of chemicals from an old type of cleaning solvents no longer in use.
The solvents contained chlorinated hydrocarbons — organic compounds of hydrogen and carbon to which chlorine has been added. They can cause liver and kidney damage, and have been shown to cause cancer in laboratory animals.
The groundwater flows to the southeast, so the pollution oozed underground beyond the utility's property line to contaminate the area under the county park, too. It has not reached the reservoir.
Progress Energy's cleanup plan calls for sinking monitoring wells in the park and on Progress Energy's land, then pumping out the contaminated groundwater for treatment and injecting bacteria in its place to consume what's left.
As to why 14 years passed between the discovery of the Walsingham pollution and the start of a cleanup, "The project has required multiple stages of assessments," Grant said in an e-mail.
The long delay echoes a similar situation that occurred with the Raytheon factory near Tyrone Square Mall in St. Petersburg.
Workers building a leg of the Pinellas Trail next to the Raytheon plant found groundwater pollution in 1991. Despite cleanup efforts then, Raytheon and DEP officials learned in 1999 that the plume had spread beyond Raytheon's property to the surrounding Azalea neighborhood. But no one alerted the neighbors to the situation until 2008.
DEP officials approved Raytheon's plan for cleaning up the pollution earlier this year.
Craig Pittman can be reached at email@example.com.