BNSF Railway will be working in the Whitefish River on Wednesday, Aug. 7 following a report of a petroleum sheen in the river.

The company is investigating a complaint of a petroleum sheen received by the Montana Department of Environmental Quality in the river near the Whitefish Landing river access site, according to Maia LaSalle, Public Affairs Director for BNSF.

“We continue to work with Montana DEQ, [U.S. EPA] as well as the City of Whitefish in regards to that report,” LaSalle said in a release.

Access to the area will be controlled due to heavy equipment operating in the area near the river access site in the morning on Wednesday. The park, sandwiched between the river and the city’s bike path, just west of the intersection of Miles Avenue and Railway Street is near the BNSF roundhouse.

A major cleanup of the Whitefish River was completed by BNSF in 2013 involving the excavation of petroleum-contaminated soils in the river.

Mayor John Muhlfeld on Monday said a citizen complained of seeing a petroleum sheen about 20 feet in length in the river, about 15 feet off shore from the public access point.

“BNSF sent an investigative team out and they agitated the sediments in the river,” he said. “They followed up and pressure washed the river bottom to see if they could find where the sheen was coming from, but the sheen is still there.”

Muhlfeld said on Wednesday BNSF plans to use an excavator in the river, along with appropriate precautions to protect the river.

“They are looking to further investigate and characterize where the sheen is coming from,” he said. “They expect it’s probably coming from an upland area, meaning an area between the roundhouse and the shoreline of the river. Perhaps the liner they have in place to intercept any residual petroleum is not functioning.”

Muhlfeld said he expects BNSF to keep the city updated on the process.

The previous cleanup of the river lasted five years and was initiated after the U.S. Environmental Protection Agency received a report in 2007 of an apparent sheen at several locations along the river. Citing the Oil Pollution Act, EPA ordered BNSF to clean up petroleum contamination from the river sediment at several sites and to restore it to as close to pre-removal conditions as possible.

BNSF removed more than 26,000 cubic yards of contaminated sediment and backfilled it on more than 1.5 miles of the river during the effort. Re-vegetation was also completed along the river.

The Whitefish Landing along the river was used during cleanup as a staging area. The railway owns the property, but a long-term lease with the City of Whitefish was established to maintain public access to the river.