Flammable vapors collected, then ignited in a seismic explosion after employees at a paint and ink factory shut off a ventilation system that neighbors had complained was too noisy, investigators said Wednesday.
The blast damaged 270 homes and businesses in the Danversport neighborhood and was felt 25 miles away. Sixteen homes and six businesses were ordered demolished, but no one was killed or seriously injured in the Nov. 22 explosion.
The U.S. Chemical Safety and Hazard Investigation Board concluded in a preliminary report released Wednesday that solvents, left stirring overnight in an unsealed mixing tank, released flammable vapor that accumulated and ignited.
A ventilation system that would have prevented the buildup was routinely turned off as each workday ended, because of noise complaints from neighbors and to prevent heat loss in winter, said John Vorderbrueggen, an investigator with the board. He said investigators do not know what ignited the vapors.
Reportedly out of compliance with fire codes
The investigators also found that ink manufacturer CAI Inc. and Arnel Co. Inc., a custom paint maker, were not in compliance with fire codes and did not have the proper permits for handling flammable solvents.
"The (companies) did not comply. If they had complied, this incident would not have happened," said Carolyn Merritt, chairwoman of the chemical safety board.
CAI said in a news release that it "strongly disagrees" with the findings and urged a more complete investigation. The company is conducting its own probe.
"An eagerness to determine cause in an event of this magnitude is understandable and expected," the company said. "However, a rush to judgment without the benefit of an exhaustive review is inappropriate and can improperly influence the scope of an investigation."
A message could not be left for Arnel because its voice mail system was full.
Earlier this week, state inspectors announced they would target small companies handling dangerous materials in residential areas to try to prevent a similar tragedy.