Operations back to normal at Clearwater Paper plant

Operations have returned to normal at Clearwater Paper in Lewiston following an explosion that reportedly was heard by residents within a few miles of the plant.

The mixing tank that was damaged was online by mid-week about 12 days after the explosion, and that made it possible to run the No. 4 recovery boiler again, said Matt Van Vleet, a spokesman for Clearwater Paper.

The No. 4 recovery boiler didn't need significant repairs, but it couldn't operate until the mixing tank was fixed, Van Vleet said.

Van Vleet continued to decline to answer questions about how much damage the explosion caused. The production lost was "nonmaterial" since Clearwater Paper shifted functions around to other parts of the mill.

The explosion occurred when Clearwater Paper was bringing the plant online after a lightning storm disabled its two connections to Avista, its electrical provider. Clearwater Paper, with help from Avista, is evaluating steps that can be taken to prevent that from happening in the future, Van Vleet said.

The mixing tank is where chemicals used in pulpmaking for tissue and paperboard go after they're isolated in the No. 4 recovery boiler as part of a recycling process.

The hot chemicals typically combine with a cooler liquid in the mixing tank and that causes a reaction when things are working as they should, but in this instance the reaction was larger than it should have been because of a higher volume of liquid.

Other parts of the complex that house paperboard, lumber and consumer tissue manufacturing were not affected.

Clearwater Paper didn't report the explosion to any governmental entity since no one was hurt and it didn't pose any environmental risks, Van Vleet has said.

The Occupational Safety and Health Administration requires reporting of fatal accidents, "catastrophes" where three or more people are hospitalized and a variety of special instances such as when someone loses a finger in a mechanical press, said Jerry Hockett, area director of OSHA in Boise.

The Clearwater Paper explosion didn't meet any of those criteria. But Hockett said that doesn't necessarily mean his agency won't look into it.

"Each time we hear of an incident, we make an evaluation," said Hockett, who didn't know about what happened at Clearwater Paper until the Tribune called.

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Williams may be contacted at ewilliam@lmtribune.com or (208) 848-2261.