BNSF Railway Co. continues to perform work on the Whitefish River related to a petroleum sheen spotted in the river this summer.

Work is still ongoing at the Whitefish Landing river access site near the roundhouse, according to an email from Maia LaSalle, public affairs director for BNSF.

“Soils with minor hydrocarbon impacts have been removed in the area, and some final work on the shoreline remains to eliminate any potential for migration to the river,” LaSalle said last week.

A pile of soil already removed from the site is being “tested for disposal and will be removed once testing and profiling is complete with a BNSF disposal facility,” LaSalle said, noting the material is not hazardous.

The Montana Department of Environmental Quality in July received a citizen complaint of a petroleum sheen in the river, according to DEQ State Superfund Project Officer Jessica Smith, and work to investigate the issue mobilized the first week of August.

“DEQ and BNSF — we were all very concerned,” she said.

Smith said clean rock was moved during the initial investigation, which appeared to create a sheen in the river, prompting further evaluation of what appears to be contamination coming from upland on the rail yard. DEQ is still waiting on results to confirm the contamination, Smith noted, but it’s assumed to be diesel.

The sheen was reportedly about 20 feet in length and about 15 feet off shore from the public access point.

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

“We want to make sure what was already cleaned up stays cleaned up,” Smith said.

The previous cleanup 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.

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.

The BNSF rail yard is designated as a state Superfund site with soil and groundwater contamination by petroleum products, chemicals and heavy metals.

DEQ continues to conduct a risk assessment to evaluate investigation work done at the site, and that will determine future cleanup, Smith noted. She hopes to have the risk assessment completed by early 2020.