Tillamook Bay was closed to commercial shellfish harvesting last week, following a massive spill of liquid manure from a nearby dairy. It was scheduled to reopen Wednesday night.
About 190,000 gallons of manure were released from an above-ground storage tank at Tony Silveira Dairy after a valve broke, said Wym Matthews, who oversees dairies for the Oregon Department of Agriculture.
The liquid manure pooled in a field near the dairy barns, flowed across three other landowners’ properties, and ended up in a slough that connects to a drainage system that pumps water into the Tillamook River, which then enters the bay, Matthews said.
ODA received several complaints about the spill on April 12. It responded that day and took 18 water samples. Follow-up sampling was done April 13, 14 and 17.
The testing showed fecal coliform readings of 130,000 colony forming units per 100 milliliters of water on the first day – more than 300 times the water quality standard of 406. Levels fell to 6,700 CFU’s on the second day, and 110 CFU’s on the third day.
There are several commercial oyster growers in the area, ODA spokesman Bruce Pokarney said. ODA does not have an estimate of the economic impact of the closure on those growers.
Matthews said he believes the Tillamook County Health Department also closed the bay to recreational shellfish harvesting. Officials there could not be reached for comment.
The dairy likely will be cited and possibly fined for the incident, Matthews said. It has operated in Tillamook County for about six years and has not had any previous enforcement actions.
Oregon State Police and the Oregon Department of Environmental Quality also are involved in the investigation.
A man who answered the phone at the dairy, who would not identify himself, said all inquiries were being referred to ODA.
The dairy supplies the Tillamook County Creamery Association, which makes Tillamook brand cheese. Officials there declined an interview request but issued a written statement saying they are actively monitoring the situation.
"The Silveiras and everyone at TCCA feel terrible this accident occurred," the association wrote.
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