In one of the deadliest nightclub fires in American history, 100 people died at a rock concert in Rhode Island nearly a decade ago. But the biggest killer wasn't the flames; it was lethal gases released from burning sound-insulation foam and other plastics.
In a fatal bit of irony, attempts to snuff fires like this catastrophic one could be making some fires even more deadly.
New research suggests that chemicals – brominated and chlorinated flame retardants – that are added to upholstered furniture and other household items to stop the spread of flames increase emissions of two poisonous gases.
"We found that flame retardants have the undesirable effect of increasing the amounts of carbon monoxide and hydrogen cyanide released during combustion," study co-author Anna Stec, a fire specialist at the University of Central Lancashire in the United Kingdom, said in a statement.
These two gases are by far the biggest killer in fires. They are responsible for 60 to 80 percent of fire deaths, according to the National Fire Protection Assn. During the Rhode Island fire, the levels of hydrogen cyanide and carbon monoxide were high enough to kill in less than 90 seconds. *(There is no evidence, however, that flame retardants were involved; the nightclub's foam insulation reportedly was not treated with them.)
Flame retardants made of brominated or chlorinated chemicals are added to furniture cushions, carpet padding, children's car seats, plastics that encase electronics and other consumer items. Under California standards adopted in the 1970s, foam inside furniture must withstand a 12-second exposure to a small, open flame, and much of the nation’s furniture is manufactured with flame retardants to meet that standard.
However, while the chemicals may be slowing the spread of flames, when fires do occur, they may be more deadly. Few details of the new research from the United Kingdom are available since the findings have not yet been published. But the researchers said in one experiment, nylon containing the flame retardant brominated polystyrene released six times more hydrogen cyanide when set afire than the same material containing a halogen-free flame retardant.
Hydrogen cyanide is 35 times more deadly than carbon monoxide, and during a fire it can kill in as little as one minute, said Todd Shoebridge, a 30-year fire service veteran who is a captain at the Hickory Fire Department in North Carolina. "It's that serious," Shoebridge said.
Both carbon monoxide and hydrogen cyanide are products of incomplete combustion. As a room on fire loses oxygen, combustion becomes less efficient and gases and smoke rapidly increase. Inhaling the toxic air becomes unavoidable for people trapped in a fire.
Brominated and chlorinated flame retardants work by interfering with combustion, which can increase the amount of the gases.
The evidence "leads one to assume that these chemicals could increase fire safety concerns, not decrease them," said Heather Stapleton, an environmental chemist at Duke University who specializes in studying brominated compounds.
The new research focused on brominated polystyrene, a newer flame retardant manufactured by Albemarle Corp. and other companies. It is added to nylon for use in textiles, upholstery and electrical connectors.