The state Department of Ecology confirms it’s investigated a fuel spill first reported online Wednesday by local wildlife biologist/advocate Kersti Muul. She received photos including the ones she gave us permission to republish here – showing the sheen on the water off Harbor Island and the West Seattle Bridge.

Here’s how Ecology spokesperson Ty Keltner responded to our inquiry:

There was a spill a couple days ago in the Duwamish. Ecology got multiple reports of sheen near the southeast end of Harbor Island. The source of the spill is believed to be the tug Westrac II. The tug reported a spill of 40-50 gallons of hydraulic oil to due to an engine drive unit issue. Ecology Spill Responders went out to determine if anything could be recovered and to ensure the vessel is no longer spilling. We sent out a responder again yesterday to see some of the leftover sheen, but it’s very weathered and there isn’t much we can do for recovering what is left.

Kersti notes, “We should continue to keep eyes out for wildlife and pockets of concentrated oil.” The state hotline for reporting a spill is 800-OILS-911.