Investigators for the Occupational Safety and Health Administration say the Redhook Ale Brewery’s keg-washing equipment was operating at a pressure that exceeded the maximum threshold recommended by the manufacturer of the plastic keg. Ben Harris was emptying the keg with pressurized air when it blew apart at the seams in April, killing him.

The parent company of Redhook, Craft Brew Alliance, tells Foster’s Daily Democrat that it did not willfully violate workplace safety standards. It said issues raised in OSHA’s citations have already been addressed.

Craft Brew Alliance said the keg was mistakenly delivered to Redhook as part of a delivery of empty keg returns.

“The Portsmouth brewery uses compressed air to push waste beer out of returned kegs prior to washing and filling,” the company said in a statement Tuesday. “The brewery believes it was operating safely because it has historically washed and filled only stainless steel beer kegs without incident. Redhook had never worked with plastic beer kegs at the time of the accident and has implemented policies to ensure that plastic kegs are not processed.”

The company added that Redhook has installed pressure reducing and relief devices to ensure that no incoming keg is exposed to excessive pressure.