US says force of explosion was blunted

People probably would have died if the massive industrial explosion in Danvers last week had not occurred in the middle of the night when residents were protected in their beds, according to an initial assessment released yesterday by federal investigators.

The findings of the US Chemical Safety and Hazard Investigation Board were issued after three site inspections and interviews with employees from Arnel Co. Inc., one of the two firms that occupied the building that exploded about 2:45 a.m. on Nov. 22. The other company was CAI Inc., an ink manufacturer.

"This was a powerful explosion, even compared to other significant chemical accidents," said John Vorderbrueggen, the safety board's lead investigator. "More than 30 windows were broken at a high school one half-mile from the explosion origin."

Eleven federal investigators were on scene yesterday to examine and photograph the debris and interview residents. The team hopes to calculate the nature of the shockwave that damaged up to 70 houses and businesses.

Andrew Ryan can be reached at aryan@globe.com.