The Department of Environmental Quality has removed five groundwater cleanup systems in Riverton, mostly at former gas stations and car dealerships. They had been set up to remove excess hydrocarbon pollution caused by leaking gas tanks there. Now, the DEQ will continue monitoring the sites to make sure pollution levels weaken on their own, or at least don’t get worse.

The DEQ’s Storage Tank Program has remediated more than one-thousand sites like these since the early 1990s, starting with the worst offenders. There are about 600 left on the to-do list.

Mark Thiesse  is a project manager with the program in Riverton. He says groundwater pollution is hard to contain, but it’s a good sign when sites no longer need pumps working to remove the hydrocarbons.

"We’re certainly making progress and heading in the right direction. It just takes a long time, unfortunately."

Thiesse says clean-up sites like these have become more rare since EPA regulations began requiring companies to be more careful when storing gasoline.