MEDFORD, Ore. (AP) — Environmental cleanup is underway following a Tuesday fire at a gas station in Medford.

The Oregon Department of Environmental Quality said Thursday that over 12,000 gallons of various petroleum products, mostly lube oil, were released into nearby Bear Creek and surrounding areas during the incident.

The U.S. Environmental Protection Agency, the Oregon Department of Environmental Quality, and NEXGEN Logistics, LLC are working on the cleanup, which also involves smaller amounts of diesel, gasoline, and kerosene. Absorbent booms have been placed in the creek to help absorb the oil. Crews were also removing petroleum from the creek and its bank.

Crews on Friday morning observed small areas of light sheen on the Rogue River downstream of Bear Creek which has prompted the placement of additional hard boom – which traps petroleum – and absorbent boom into areas of Bear Creek downstream of the incident. The agencies are investigating the extent of sheen on the Rogue, DEQ said.

Above-ground tanks at the fuel business were being emptied. DEQ said the containers appeared to have remained mostly intact.

Officials also said Oregon Department of Fish and Wildlife biologists have captured and cleaned several oiled waterfowl that remain under observation. So far officials said no impacts to fish have been observed.

EPA set up community air quality monitors and said the air has remained at safe levels.

On Friday, the city of Medford identified seven businesses impacted by the fire, the Mail Tribune reported.

Authorities are investigating the fire’s cause.