Niagara Gazette — Tonawanda Coke released a statement on Wednesday explaining the cause of last week's explosion at its plant, located at 3875 River Road in the Town of Tonawanda, which company officials said was the result of the freezing of an air line that occurred due to extremely cold temperatures.
The freeze then led a blockage to form in a gas line at the plant, where coal is burned in oven batteries to produce coke — an ingredient in the steel-making process. The blockages then led to a build-up of pressure of coke oven gas in the manifold, which supplies gas for combustion in the ovens.
The pressure "resulted in a disk rupture on a manifold underneath the coke oven battery at 11:50 a.m." on Friday, the statement reads.
One minute later, the coke oven gas in that confined area combusted, and an explosion occurred.
"A small fire then burned for approximately 12 minutes before it was extinguished by on-site operators using both steam and water," the statement from the Town of Tonawanda plant reads.
No injuries were reported, and the damage was isolated to equipment and non-structural walls, Tonawanda Coke said.
The plant stressed that the coke oven gas is made up of mainly hydrogen, methane and nitrogen. Benzene, a known carcinogen, makes up less than 0.5 percent of the gas, the statement reads.
The plant said it has already taken safety measures to prevent a similar incident from happening in the future. Tonawanda Coke has expanded its preventive plan and monitoring routine and upgraded its air supply system to deal with freezing risks. A cooler was also installed to improve coke oven gas cleaning, which will minimize the risk of blockages, the statement reads.
Tonawanda Coke submitted a report to the Environmental Protection Agency, the state Department of Environmental Conservation, the state Emergency Response Committee, the Occupational Safety and Health Administration and local fire officials.
"Tonawanda Coke will continue to cooperate with the agencies during their review of the incident," the release states.
The release comes as the EPA, DEC and OSHA investigate the explosion.
Witnesses who were near the plant at the time of the incident said they heard a loud boom and saw a large black plume of smoke coming from the coal-burning facility.
Ellwood and Kenmore fire departments reported to the scene. Plant officials told the fire chiefs that an explosion had occurred due to a buildup of pressure. Firemen did not reach the scene of the incident.