CSB rules out natural gas in Danversport explosion
The U.S. Chemical Safety Board on Thursday confirmed earlier findings that the overnight build-up of overheated flammable vapors in an unventilated factory caused the explosion that rocked Danversport one year ago.
The trigger could have been "a static spark," said CSB lead investigator John Vorderbrueggen, who unveiled conclusions resulting from completed laboratory tests of the exact chemical mix in the vat at the CAI ink and Arnel paint factory on Nov. 22, 2006.
"It is very easy to ignite," he said about the large vapor cloud created in the hours after the end of the workday Nov. 21, until the explosion at about 2:45 a.m. on the day before Thanksgiving. "You could rub your foot on the carpet, and that's enough."
No one was in the Water Street building shared by CAI ink and Arnel paint companies, so the actual ignition source may never be known. The fact that the vapor cloud wasn't ignited earlier by a "ready" source and had time to become very large, he said, actually contributed to the intensity of the eventual explosion that damaged more than 100 homes, some still in shambles today.
The agency, however, ruled out natural gas or propane, which some residents of the area had questioned, since they had detected the odor of gas on many occasions and looked to KeySpan for answers.
"Personally, I trust what the CSB has to say," said Susan Tropeano, a leader of SAFE (Safe Area for Everyone), which formed soon after the explosion to investigate the cause and help neighbors through the crisis. "When it's all done, and the final reports are completed, I think people will be satisfied that their concerns were heard," she said.
State Rep. Ted Speliotis, who received a copy of the CSB press release, expressed his appreciation for this "independent review."
"I am pleased that a federal agency in charge of investigating every explosion in the nation has taken the time to be so thorough here in Danvers," he said.
At a public hearing in May, the CSB found fault with CAI and Arnel for violating safety rules by switching off the ventilation that would have prevented the explosion.
On Thursday, Vorderbrueggen reiterated that view and stated the companies did not have "safety interlocks." Such fail-safe systems, however, are not required under current fire codes. If they had been, electrical or mechanical devices could have been tied to the temperature of the chemicals at CAI/Arnel to "close a valve" or add a cooling system to prevent a disaster.
The CSB worked with people from SAFE, said Vorderbrueggen, "to track down the source of gas odors sometimes reported in the neighborhood around the CAI/Arnel facility."
But, extensive testing found no reason to believe that natural gas or propane served as a fuel "or a contributing fuel to this event," Vorderbrueggen elaborated during the conference call with reporters Thursday.
The Danvers Fire Department won some criticism from Stephen Selk, director of investigations for the CSB, because it allowed CAI/Arnel to stack many "totes" of chemicals, which held more than 55-gallons each. Such stacking and the lack of ventilation of the totes to the outside are both in violation of current fire regulations and the U.S. Occupational Safety and Health Administration (OSHA) rules, he said.
"This affected the severity of the fire" after the explosion, he said, although it did not cause the explosion.
"Overheating is not something we expect them (the Fire Department) to see," said Selk, nor is the fact that the company employees turned off the ventilation system at night, since inspections are done during the day.
"I don't think it's fair to suggest the Fire Department missed something specifically," Vorderbrueggen said about the blast itself. "The challenge is understanding the complexities."
The CSB mission is to make safety recommendations that will help prevent chemical explosions in the future. It is currently looking at oversight regulations, land-use rules and licensing of industries that store, manufacture and sell chemicals and combustibles.
Vorderbrueggen noted that the state licensing law does establish some oversight and allows public input when the license is first issued. But it does not require any public review ever again, simply a statement about the amount of chemicals on hand so that fees can be properly assessed.
The CAI/Arnel factory was operating under a license granted in 1944 to a prior owner of the land who wanted to store 250 gallons of "lacquer."
"During the 62 years that followed, the amount permitted by the license was increased to some 11,500 gallons," he said. "State law does not require any safety review or public impact review when a licensee obtains increases in registered quantity."
He would not state if the CSB would recommend such changes, since the CSB, which is an independent federal agency, is still looking at changes under consideration by the state and other communities across the country.
The final report awaits more internal reviews and the CSB board vote. A public hearing to convey those final recommendations is expected in April 2008.