TUKWILA, Wash. -- A cleanup crew worked to control contamination in the Duwamish River Wednesday night after a semi tractor-trailer jackknifed on Interstate 5 caused as much as 100 gallons of diesel fuel to run into a storm drain and then into the river.

The truck jackknifed south of Boeing Field, causing traffic to come to a crawl. It is not known how much fuel actually drained into the river.

Crews put in absorbent pads around the mouth of the storm drain that dumps into the river. On Thursday morning, KIRO 7 Eyewitness News reporter Jeff Nguyen, who was several miles downriver from the spill, said sheen could be seen on the water of the Tukwila river and a smell of fuel was in the air.

Coast Guard crews said they will continue to watch the river and take measures to control the contamination if necessary.