Chemical vapor that accumulated inside a paint and ink factory fueled the huge explosion that leveled the building and damaging dozens of surrounding homes last fall, according to a preliminary conclusion by federal investigators.
The Chemical Safety and Hazard Investigation Board's lead investigator, John Vorderbrueggen, said authorities also are looking into the possibility that natural gas collected inside the building, which was used by ink manufacturer CAI Inc. and Arnel Co. Inc., a custom paint maker.
Both companies used highly solvent chemicals, he told The Boston Globe for Saturday's editions.
"If you can't control the vapors, then you minimize them," he said. "In this situation, we apparently had neither of those features. We didn't minimize the vapors, and we didn't control the vapors. We didn't ventilate it safely out of the building. And then it found an ignition source."
There was no immediate response Saturday to a call seeking comment from an Arnel office in Salem.
CAI issued a statement calling the preliminary report was unexpected and premature.
"It is simply too early in the investigative process to determine with any degree of certainty what caused the blast," the statement said.
The early morning blast Nov. 22 in Danvers, 17 miles north of Boston, damaged 70 houses and businesses and made hundreds homeless, though no one was killed or seriously injured.
Because the factory was destroyed, investigators may never learn what ignited the fumes, Vorderbrueggen said.
A spokeswoman for State Fire Marshal Stephen Coan said the state investigation had not yet reached a conclusion.
http://www.redorbit.com/news/science/826211/fed_panel_blames_vapors_for_mass_blast/index.html?source=r_science
