Six months after starting up, Clatskanie’s new ethanol plant shut down indefinitely Thursday night because technical problems may be contaminating its product.

“We have two independent labs. One lab says we don’t have a problem, and another lab says we do have a problem,” said Charles Carlson, president and chief executive officer of Cascade Grain LLC.

“At this point we are unsure if we even have a problem. We are trying to examine all aspects of our operation to see if there is a problem in the process, and resolve it if that is the case.”

He said the plant’s 59 employees will remain on the job for now.

“We don’t have intentions to lay people off unless we can’t find it (the problem). We’re still in the investigative stage.”

Shipments of corn, the raw material from which ethanol is produced, will cease until Cascade figures out the situation, Carlson said. Corn shipments come in long unit trains, and the plant only has capacity to store two such shipments on site.

The $200 million plant, located at Port Westward north of Clatskanie, produces ethanol for use as a gasoline additive. It went into operation June 6 last year.

One lab has found Cascade Grain’s finished ethanol contains too high a concentration of sulfate, Carlson said, saying officials have to figure out why there is a discrepancy with tests conducted by another lab. Both laboratories are based in Portland, he said.

Meanwhile, “there’s no sense producing a product we can’t sell.”

He said the production processed used at the Port Westward plant is not known for having sulfate problems, so the development was unexpected.