A hydrochloric acid spill created a 6-mile backup on southbound Interstate 405 just over the Cedar River Friday around noon, according to the Washington State Department of Transportation.

A Toyota pickup truck was carrying the acid, commonly used to clean pools, when the driver noticed that it began to leak, according to Larry Altose, a spokesperson for the Washington State Department of Ecology.

“The bulk of the spilled material was in the bed of the pickup truck,” he said. “The river was not impacted, because there was nothing that drained into the river.”

The driver pulled over when she noticed the leak, and called for help. About a gallon was lost, he said.

Two lanes on the right hand were cleared at about 1:30 by Renton firefighters.