Inspections to Target Small Firms in Mass. Handling Dangerous Materials

State inspectors in Massachusetts will target small companies handling dangerous materials in residential areas to try to prevent a repeat of a Danvers explosion that was blamed on a build up of chemical vapor.

The state fire marshal’s finding released this week supports a preliminary conclusion by federal investigators that the vapor build up of a chemical used to make ink caused the blast at a paint and ink factory Nov. 22, damaging 270 homes and businesses and leaving hundreds homeless. No one was killed or seriously injured.

The explosion — felt 25 miles away — leveled the building used by ink manufacturer CAI Inc. and Arnel Co., Inc., a custom paint maker. Both companies used highly explosive chemical solvents in manufacturing, investigators said.

State Fire Marshal Stephen Coan’s probe focused on a processing area shared by the two companies. He said CAI’s ink-producing process involved heating chemicals, including heptane, in a large “mixing vessel,” then shutting off the heat.

“Witness interviews have led investigators to conclude that one of the chemicals involved, (1,000 gallons) heptane … was most likely overheated due to a failure to turn off the steam heat system,” Coan’s report stated.

The ignition source could not be determined because the building was destroyed, Coan said, but possibilities included refrigerator and vending machine motors and condensers, space heaters, electrical exhaust fans and the furnace.

CAI officials said in a statement that while they have cooperated fully with the investigation, they could not comment on the fire marshal’s report because “we have not been provided with the basis supporting their assumptions.”

The company is conducting its own investigation.

“(The explosion) demands a comprehensive investigation equal to the task — an inquiry that employs advanced technology and expertise, and which thoroughly explores all potential avenues of cause,” the statement said.

Arnel officials did not return phone messages left by The Associated Press.

Sixteen homes and six businesses were ordered demolished as a result of the blast, Coan’s investigation found. More than 300 cars and trucks, as well as 65 boats, were damaged or destroyed.

The U.S. Chemical Safety Board planned to release the results of its investigation on Wednesday. Spokesman Daniel Horowitz declined to discuss the specifics of those findings ahead of that meeting.

A new inspection program was unveiled along with the cause in hopes it will prevent similar problems. Inspectors from the Department of Environmental Protection, Department of Fire Services and local fire departments will conduct hazard assessments at small- and mid-sized companies.

If companies resist, “access may be compelled though various means, up to and including administrative search warrants,” according to a news release.

Inspectors already have identified 40 facilities across the state, selected because of proximity to densely populated areas, types of chemicals or waste materials used and stored and site history. The first 15 will be inspected in the next two months.