The Pennsylvania Department of Environmental Protection issued its findings Monday after an investigation of a chemical spill at the Erie Coke plant late Sunday afternoon.

The spill occurred at a wastewater treatment plant the company operates on site.

According to the DEP, a hole developed in a large, above-ground storage tank March 18. Erie Coke personnel repaired the hole by welding a large metal plate to the tank. The tank failed Sunday, causing a large volume of wastewater to be released onto the ground and into surrounding structures at the facility.

The wastewater contains, among other regulated substances, benzene, naphthalene, ammonia, and cyanide, the DEP said. According to the agency, Erie Coke committed several violations during the repair of the tank and the cleanup of the spill.  The incident constitutes unlawful conduct and the release of the wastewater creates a danger of pollution to the waters of the Commonwealth, according to DEP.

DEP is ordering Erie Coke to take the tank out of service, remove all wastewater from the tank and have a certified professional conduct a tank tightness test within 10 days of the order.

Erie Coke shall submit a plan to remove all wastewater from the tank within 3 days of the order. Within 60 days of the order, the wastewater and impacted soils and material shall be properly characterized and disposed at a permitted facility.

Within 45 days after the date of the order, Erie Coke shall inspect all piping, sensors, alarms and containment structures associated with the tank to determine structural integrity.

Erie Coke can appeal the action to the Environmental Hearing Board.