A Salem, Ore., firm has been fined $9,000 by the Washington Department of Ecology for chemical spills last year during work under I-405.

Michel’s Pipe Services was cited for the July spills that occurred near Southeast Eighth Street.

It also issued a warning letter to the Washington State Department of Transportation for not properly supervising the situation.

According to the Ecology Department, the subcontractor used air pressure and steam to install a plastic lining in a 24-inch culvert that carries Trail Creek beneath I-405. The creek’s water flow was diverted during the operation. On July 15, an unexpected flow of groundwater interfered with the process, and Michel’s used an inflatable plug to block that flow, the state release said. The plug failed. Some resin entered the creek and was not reported.

Odors from the creek led to a state investigation. The Ecology Department found in the water mineral oil and styrene, which is poisonous to crayfish and other crustaceans. Dead crayfish were found.

A similar plugging failure occurred the next night when the contractors tried to repeat the operation. This time, it was reported to the state.

The Bellevue Parks Department closed trails around the spill to prevent people being exposed to toxic compounds.

Styrene odor remained in the area until at least July 24.

Michel’s has 30 days to appeal to the Ecology Department or to the Washington State Pollution Control Hearings Board. It plans to do so, the state news release said.