DANVERS — It was the middle of a Tuesday afternoon when the production manager at CAI Inc., a Danversport ink manufacturer, opened the steam valve on Mix Tank No. 3 to heat a new batch of chemicals.
While waiting for the 2,000-gallon chemical soup to warm up, the manager and a few workers started unloading a shipment of resin and pigment from a truck parked at the Water Street facility. When they finished, they began loading the same truck with that day's production of ink.
Around 5 p.m., the manager went back inside the plant to check on the temperature of the tank, which had reached about 90 degrees.
And then he says he took one final step.
"I believe I closed the steam valve," said the manager, who was not named in a report released yesterday.
A half-hour later, he left for the night. Shortly before 6 p.m., the last worker turned off a few fans and locked the building.
And at 2:46 a.m. the next day — nearly nine hours later — a cloud of vapors found an unknown ignition source and exploded. The blast shattered windows miles away, damaged more than 100 homes and businesses, and forced the evacuation of 300 people.
Incredibly, nobody was killed and only about a dozen people went to the hospital for minor injuries.
However, it did untold millions of dollars of destruction, uprooted families and caused the worst damage to a community the U.S. Chemical Safety Board has seen in its 10-year history.
Although Chemical Safety Board investigators don't know for certain what happened on Nov. 21, 2006, they concluded that the production manager forgot to shut off the steam heat valve before leaving.
They reached that conclusion after a 15-month investigation that included dozens of interviews with workers and officials, an analysis of debris from the site, a laboratory re-creation of the chemical mix in the tank, computer blast modeling, and the first detailed accounting of events that day. The investigation culminated yesterday with the release of the 105-page report.
That report concluded that the heat from the open steam valve caused a volatile mixture of heptane and propyl alcohol to boil, releasing a potentially deadly cloud of vapors into the building.
That might not have been a problem, investigators said, if workers at CAI didn't routinely close the ventilation system at night to keep the building warm and to keep down complaints from neighbors about the noise from a fan.
That combination of an overheated tank and a building without ventilation proved a "perfect storm," according to John Vorderbrueggen, the Chemical Safety Board's lead investigator.
'Foreseeable error'
One point the federal agency stressed yesterday is that it didn't do this exhaustive investigation to place individual blame.
"It is not his fault," Vorderbrueggen said of the CAI manager, in a brief interview following yesterday morning's press conference. "It was not negligence. ... It was human nature" to get distracted and forget to shut off the valve. "The mechanical system just invited an opportunity to make such a mistake."
But the federal agency faulted CAI for not having systems and equipment in place to prevent the explosion.
"The company did not have automated process controls, alarms or other safeguards in place ..." said Chemical Safety Board member William Wright.
The manufacturing process at CAI did not meet standards set by the federal Occupational Safety and Health Administration, and CAI "was unaware of the OSHA standard," the board stated.
The company also did not have required permits and failed to conform to state chemical-storage standards, the report states.
The Salem News contacted CAI, but the company had not returned the call or issued a statement as of late yesterday. When a preliminary report was released last year, CAI "strongly disagreed" with the findings and said its own investigation was still underway.
CAI shared the Water Street facility with Arnel Co. Inc., a maker of stains, lacquers and paints. However, the investigation did not focus on Arnel because it did not have the same quantity of chemicals and did not have a manufacturing process underway at the time of the explosion, the board said.
Lack of oversight
The state fire marshal, meanwhile, who did his own investigation, has taken out court complaints and issued fines against both CAI and Arnel for storing twice as much hazardous chemicals as their licenses allowed.
The Chemical Safety Board report also points out shortcomings in government agencies from the federal to local levels.
For example, the fire codes developed by the National Fire Protection Association "do not provide sufficient safeguards for flammable liquids heated inside buildings," the report states.
Massachusetts, the board noted, does not specify how often local fire departments should inspect manufacturers with large quantities of flammable liquids or what they should inspect.
The Danvers Fire Department had not inspected the CAI plant since 2002 and went there that time largely to check on a new foam fire suppression system that had been installed.
The board also pointed out major problems with the licensing of chemical plants. The CAI/Arnel plant had a land-use license for flammable liquids, but only for 6,000 gallons — not the 20,000 gallons at the Danvers plant, nor the additional 50,000 pounds of nitrocellulose, a flammable solid.
In addition, at the time of the explosion, CAI and/or Arnel had only an expired permit for an underground storage tank.
The federal agency also noted that Massachusetts laws do not require a new license or a public hearing when a facility increases the amount of flammable chemicals. CAI upped the amount of chemicals several times over the years, the report stated.
In the end, the Chemical Safety Board said it was lucky this disaster wasn't worse.
"... I share with the community the astonishment no one was killed or more seriously injured in this accident," Vorderbrueggen said.
Tom Dalton may be contacted at tdalton@gloucestertimes.com.
Key findings
r The steam valve on Mix Tank No. 3 was inadvertently left open overnight;
r The mix tanks were not equipped with automatic shutoff controls or alarms;
r The mix tanks were not designed to be sealed and were not vented to the outside;
r CAI personnel turned off the building ventilation;
r CAI and Arnel did not have Fire Department permits to store flammable liquids and solids;
r More than four years had elapsed since last Fire Department inspection;
r Danvers did not have a Local Emergency Planning Council at the time of the incident.
Key recommendations
r The National Fire Protection Association should prohibit heating flammable liquids above their flash points in tanks inside a building unless the tanks are sealed and vented to the exterior;
r The Massachusetts Legislature should require new and current manufacturers to submit written certification to local governments stating that facilities comply with all state and local fire codes and hazardous chemicals regulations as part of annual registration renewals;
r The state Office of Public Safety should specify how often fire departments must inspect manufacturing facilities and establish written inspection criteria;
r The town of Danvers should require new and current manufacturing plants to certify annually in writing that they comply with all state and local fire codes and hazardous chemical regulations; it should require annual Fire Department inspections; and it should re-register any companies that increase the amount of flammable materials or add different chemicals, and require the public be informed.
