PORTLAND, Ore. (From news reports) - A train derailment at the Georgia-Pacific Mill in Toledo, Ore. spilled about 2,000 gallons of diesel Friday, Feb. 10, and state officials said some of it entered a slough that feeds into the Yaquina River.

The Oregon Department of Environmental Quality responded to the emergency Friday. Officials said some of the spilled diesel may have entered a storm drain that flows into the nearby Depot Slough, which feeds into the Yaquina River.

"This is a difficult number to calculate because there is no easy [way] to measure how much fuel is in soil or how much fuel was recovered from the stormwater system versus how much made it beyond the containment measures," Oregon DEQ spokesperson Dylan Darling explained.

On Friday, crews placed a barrier in the slough to prevent the fuel from spreading. They also used an oil-absorbing boom and other absorbent materials within the barrier and around the spill site to prevent additional fuel from spreading.

As of Monday, Darling said there was an oil sheen near the outfall in a slough that connects to the Yaquina River, but no diesel has been seen in the river yet.

The train that derailed is owned and operated by Portland & Western Railroad. The cause of the derailment is under investigation.

The cleanup is not complete and Oregon DEQ doesn't have an estimate on how much it will cost.