State brings in the big guns to clean up old gas

Wednesday, March 21, 2007

By PJH Staff

Jackson Hole, Wyo---The Wyoming Department of Environmental Quality will ramp up its efforts to purge downtown Jackson of spilled contaminants this summer.

Troublesome gasoline leaks from underground tanks are the biggest concern, with state agencies battling cleanup logistics for over a decade.

Beginning May 15, DEQ will launch a more aggressive campaign against a nasty constituent of petroleum: benzene.

The problem began in the 1970s, when Bill Hansen’s gas station, Bill’s Standard, began operation at West Broadway and Millward. Hansen began noticing an unexplained and unaccountable fuel inventory loss.

“Word was, Bill thought his employees were stealing from him,” said town engineer Shawn O’Malley.

“We had all sorts of drivers coming and going and we never had leak detection go off,” Hansen recalled. Through the years, Hansen repeatedly called DEQ and other state and local officials, but investigations turned up no definitive answers.

“Finally, I filled the tanks and pumped no gas for 24 hours. That’s when I knew. We dug up everything.”

The leak, occurring between 1973 and 1985, put some 187,000 gallons of gas in the Jackson aquifer, 30 to 40 feet below ground. To date, DEQ has spent nearly $6 million on this Jackson spill according to Doug Gilmer, DEQ project manager for storage tank remediation program.

“We are nowhere near being done,” he added. “Bill’s [Standard] happens to be a very, very large site. When we first started, we had no idea it was so big. We have it now fully delineated, and we have contamination data for a couple of years now, and that has allowed us to design a cleanup.”

The cleanup of what is being called “Bill’s Standard Plume” has involved drilling wells at various locations in town and forcing oxygen underground into the aquifer. Oxygen assists in a naturally occurring process of biodegradation that destroys benzene, a carcinogen. Eighteen wells were drilled with all but six still in operation today.

“We’ve shrunk the plume in the five years where we have been doing active remediation,” Gilmer said.

However, recent charting (see map) has shown the overall perimeter to be growing and headed southwest, toward Flat Creek and the city’s drinking water supply.

“We’re trying to figure out if it is following the topography and heading for lower ground,” said O’Malley, who has ordered several test well sites be drilled and monitored in Karns Meadows. “But indications are it is being carried along by underground water flow.”

No increase in benzene levels or any other contaminant has been detected by the test wells. FDA maximum contaminant levels (MCLs) allow for five parts of benzene per billion.

“Anything over that is deemed a risk to humans,” Gilmer said. “There is no imminent threat to Flat Creek or town wells. We have all looked very, very carefully at that.”

“We will catch it long before it gets to the city’s water supply and drinking water,” assured O’Malley, adding that the neighborhoods above the plume are not affected in any way.

The city’s water supply was threatened recently when tetrachloroethylene (PCE) – a manufactured chemical widely used in the dry cleaning of fabrics, metal degreasing and taxidermy – was found in low levels in the groundwater in 2002-03 around the Virginia Lane-Gregory Lane area.

PCE has never been detected in the town’s water supply.

The stepped-up efforts by Wyoming DEQ will involve major construction of two soil vapor extraction (SVE) sites.

“It’s very expensive,” Gilmer said of the process, expected to commence May 15. “We will be between Simpson and Hansen, and Clissold and Millward.”

Manpower on the SVE sites is expected to include a crew of 20 for both sites with a summer bill adding up to $1 million, according to Gilmer.

Wyoming DEQ is footing the cost of the entire cleanup through the Water Pollution from Underground Storage Tanks Corrective Action Act. Efforts to sue the firm hired by Bill Hansen to install the original faulty tanks have been unsuccessful.

“They weren’t even bonded, we later found out,” Hansen said. “Their parent company, in California, went bankrupt.”

Hansen feels he made every effort to find and report any leak he had while he owned the gas station.

“I did everything I could do. The outfit I hired was on a state approved list. They were at the top of the list. I believe they even had their offices right next door to the DEQ in Lander.”

Gilmer agreed that Hansen was not to blame for the leak.

“The owner of the property did everything he could do to keep track of these tanks,” he said.

“He is as clean as a whistle. He did everything he could do. The company he hired to do tanks and lines did a lousy job.”

Courtesy Image. The light blue-shaded area indicates the benzene plume's movement toward Karnes Meadow, Flat Creek and the town's drinking water supply.

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State brings in the big guns to clean up old gas | Planet JH News Article: General Environment

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