Manufacturer’s procedures had warned against water in oxygen-limiting silo
The National Institute for Occupational Safety and Health released a report this month detailing how standard firefighting tactics may have contributed to a deadly explosion at a Maine lumber mill.
The May 15 fire and explosion at Robbins Lumber in rural Searsmont killed three people, including two firefighters, and injured at least 13, according to Maine authorities.
At the scene, firefighters responded to a fire at the base of a silo and flowed water into the structure. The silo was an oxygen-limiting type, designed to store combustible materials in a low-oxygen environment to prevent ignition.
The manufacturer’s emergency procedures for the silo explicitly cautioned against using water or foam. “The document warns against spraying water or foam into the oxygen-limiting silo as it will force air in and may create a potentially explosive mixture,” the NIOSH report states.
Federal investigators concluded that the water application “likely entrained oxygen into the silo headspace, stirred up dust within the contents, and caused it to become suspended in an explosive concentration,” according to the report.
The resulting explosion toppled the silo and engulfed the surrounding area in fire, Maine authorities said.