A massive manure spill at the Port of Tillamook Bay discharged roughly 300,000 gallons of treated liquid excrement into the area, some of it reaching waterways mere miles from the ocean.

Oregon state officials have yet to shut down Tillamook Bay or impose restrictions on commercial and recreational shellfish harvesting, as they’ve done during prior manure mishaps.

The state’s Department of Environmental Quality and Department of Agriculture are analyzing water samples from the bay and from around the spill site, including Anderson Creek, a tributary of the Tillamook River.

They expect to have preliminary results by Wednesday morning, said Lauren Wirtis, a spokeswoman for the environmental agency.

The manure had been held in an anaerobic digester tank, which breaks down dung into biogas that can be used for electricity and fertilizer for farms and agriculture.

The process creates a waste with fewer pathogens. That, in turn, makes it far less harmful than raw sewage, Wirtis said.

It’s not yet clear how or when exactly the spill occurred, said Michele Bradley, the Port of Tillamook Bay’s general manager. Port workers discovered the spill Monday morning and contacted state authorities, she said.

Some of the waste entered the port’s stormwater system, which empties into a section of Anderson Creek about 2 ½ miles from the Tillamook River.

Regenis, a tenant of the port that operates the manure digester, could not be reached for comment.

State officials in 2017 temporarily closed Tillamook Bay after a nearby spill caused more than 190,000 gallons of manure to enter the water.

Tony Silveria Dairy, which operated the faulty manure tanks, was later fined nearly $17,000.

-- Shane Dixon Kavanaugh; 503-294-7632

Email at skavanaugh@oregonian.com

Follow on Twitter @shanedkavanaugh

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