GLENWOOD SPRINGS – An accidental discharge of a bleach mixture from the Hot Springs Pool into the Colorado River Tuesday morning was the likely cause of a large fish kill downstream from the pool’s outflow pipe.

Steve Gunderson, director of the Colorado Water Quality Control Division, said the pool’s management filed a report to the agency indicating that about 190 gallons of 10 percent bleach mixture was discharged into the river by mistake between 11:30 a.m. and 2:30 p.m. Tuesday.

“It was a maintenance error,” Gunderson said. “Instead of going where it was intended, it went directly into the river.”

About the same time Tuesday, the Colorado Division of Wildlife was called in to investigate a large fish kill in the same vicinity near Two Rivers Park.

According to DOW spokesman Randy Hampton, a total of 84 dead fish were found along the shore and in the river, and biologists were on hand to conduct water quality and temperature tests to determine the cause.

“We didn’t have any additional dead fish today, but we are continuing the investigation as to the cause,” Hampton said. “We’re still looking into everything, but we believe the fish kill is related to the spill.”

Hampton said it was likely an isolated event with no long-term effects on river water quality.

“With a spill like that it’s not an ongoing problem. The water dilutes it pretty fast,” he said.

Gunderson said that any sudden change in the PH level of the water or temperature change can cause a sudden fish die-off.