May 27, 2014

An anhydrous ammonia leak from a West Central Cooperative storage tank in Halbur led to the deaths of numerous small fish in a 2-mile stretch of Brushy Creek on Saturday.

The leak - which was caused by a pipe that broke between two large storage tanks - was reported to the Iowa Department of Natural resources about noon that day, said Brian Young, an environmental specialist for the DNR.

"Nobody knows what caused it to blow apart," Young said of the pipe. "There is not much cleanup needed."

The leak released an ammonia gas - a crop fertilizer that in high concentrations can be fatal to humans if inhaled - and firefighters who responded to the leak sprayed water that captured the vapor but carried the ammonia into the nearby creek, which led to the fish kill.

It's unclear how much ammonia escaped the 30,000-gallon storage tank, said Alicia Clancy, a West Central spokeswoman.

"We really appreciate the volunteer fire department in helping keep us safe," she said. "It's protocol to douse the anhydrous leaks with water. You put a lot of water on it to reduce the gas. ... But all that water flowed into Brushy Creek.

Clancy said West Central and DNR workers assessed the cause of the leak and cleanup efforts on Sunday and Monday.

The dead fish included minnows, shiners and chubs, but Young did not have an estimate of how many.

Young said his department will continue to monitor the cleanup efforts, including whether contaminated soil might need to be removed from the area.