Authorities estimate that two to five dump truck loads of petroleum coke spilled into the Columbia River near Longview Tuesday morning. They are continuing to look into the source of the contamination.
"We've sent samples into the lab and we're trying to confirm whether the source is who we think it is," Jim Sachet, the region's spill response team manager for the state Department of Ecology, said Friday.
On Tuesday, Sachet said Chinook Ventures in west Longview is the largest handler of "petcoke" in the area. He said Ecology officials interviewed Chinook employees Tuesday afternoon.
Two spill responders canvassed the shorelines at Willow Grove County Park and County Line Park on Thursday and didn't find any traces of petcoke at either location, Sachet said.
"It appears as though what was released Tuesday has been dispersed," Sachet said.
Responders who viewed the mile-long slick Tuesday from a helicopter estimated that 25 to 50 cubic yards of the substance was deposited into the river. No cleanup will be conducted.
Sachet said it's too early to determine what violations were committed and what fines might be handed out.