contributed photo An unattended fuel station in Eldora leaked an estimated 7,500 gallons of gasoline into the ground.

State officials are working to determine whether groundwater contamination occurred when an unattended fuel station in Eldora leaked an estimated 7,500 gallons of gasoline into the ground last week.

Workers excavated concrete and soil throughout the weekend at the Fast Stop on the east side of town that is operated by agricultural cooperative AgVantage Farm Supply, said Carl Berg, an environmental specialist for the Iowa Department of Natural Resources.

“They haven’t hit groundwater yet,” Berg said Monday morning. “It just all depends on the geology and the location of the leak. … If it’s not contained, it can be significant.”

If the fuel reaches groundwater, it might travel away from the site and contaminate a larger area, he said.

Credit union employee smelled gasoline

AgVantage notified the DNR of the leak Friday morning. An employee of a nearby credit union first discovered the leak when the building’s basement had the smell of gasoline.

MEMBERS1st Community Credit Union closed the Eldora location indefinitely.

“We are working with the local authorities to ensure everyone’s continued safety prior to reopening the Eldora branch location,” said Janet Borer, the chief executive of the credit union.

She said employees did not find any actual fuel inside the building, and that the credit union might open a temporary site if the closure is prolonged.

AgVantage did not respond to a request to comment for this article. It is required to remove all contaminated soil and might be fined by the DNR.

The fueling station is located on a small corner lot and sells gasoline and diesel from underground tanks. The station has a system to help detect leaks, Berg said, but it didn’t alert. The precise source of the leak wasn’t immediately clear.

Eldora draws drinking water from two wells that are about a half mile away, according to DNR data. They reach depths of about 260 and 290 feet.