The U.S. Environmental Protection Agency on Feb. 9 sued Michael’s Convenience Stores Inc., seeking damages for an alleged 10,000 gallons of gasoline that leaked from a Kalispell gas station in 2007.

The civil suit, filed in U.S. District Court in Missoula, alleges the Michael’s West Exxon at West Idaho Street and Meridian Road violated the Clean Water Act when gasoline leaked from its underground piping system into the surrounding soil from May to July 2007.

The gasoline spread through the soil and groundwater, entering Kalispell’s storm-water drainage system before it eventually reached Spring Creek, a tributary to Ashley Creek.

For days, authorities worked to identify the source of the contamination as gasoline concentrations in the sewer system reached levels high enough to cause worries about an underground explosion.

At the time, the smell of gasoline was detectable from Center Street to Three Mile Drive, and the section of Meridian Road south of West Idaho Street was closed to traffic for several days.

Remedial crews removed at least 30,000 gallons of contaminated groundwater and city officials at the time estimated between 2,000 and 2,500 gallons of gasoline had spilled.

Crews used pumps, dry wells and petroleum-absorbing booms to collect contaminated groundwater. To stop the flow of gasoline into the sewer system, the city dumped concrete around a leaky sewer pipe.

According to court documents, water samples taken at the time established the presence of gasoline in Ashley and Spring creeks — both federally regulated bodies of water.

The lawsuit alleges the contamination reached levels “harmful to the public health or welfare or the environment of the United States.”

For oil pollution, a Clean Water Act violation occurs if the discharge exceeds water quality standards or if it is sufficient to cause discoloration of the water or sludge building up under the water or on the shore.

In 2006 the gas station had passed its inspection by the Montana Division of Environmental Quality.

The EPA is seeking monetary relief up to $32,500 per day of the leak or $1,100 per barrel.

For 10,000 gallons, that would come out to more than $260,000. For a period of two months, the fine could be nearly $2 million.

Michael Hayes, the store’s owner, declined to comment Monday on the litigation.

Reporter Sam Wilson can be reached at 758-4407 or by email at swilson@dailyinterlake.com.