The Deadliest Fire Hazard

Every year, when the temperatures dip to well below zero, there is an increased number of fatalities due to fire. Unquestionably, this is due largely to the overstoking of stoves and furnaces, stray cigarette butts, and other careless practices. But the burn victims comprise only a small fraction of the total casualty rate.

Statistically, fully 80 percent of fire-related fatalities occur not from burns to the victim, but to smoke inhalation.

Smoke inhalation is not a precise term, because investigators are still uncertain about what components of smoke are responsible for the high casualty rate attributed to it.

Every winter, we read about some tragic case of a family being asphyxiated in a camper or mobile home because of carbon monoxide (CO) buildup generated by a catalytic (or other) heater in an enclosed space. Therefore, CO, which is produced in the burning of almost any material, has long been considered to be the primary toxic threat in house fires.

However, a new report issued by Arthur D. Little, Inc., a consulting firm in Cambridge, Massachusetts, is questioning that assumption. The study strongly suggests that vapors given off by man-made materials are responsible for the majority of cases. A summary given of their report in the June 25 issue of Science News describes one experiment in which mice were placed in sealed chambers where they are exposed to smoke from burning materials. The lethal weight of burning material for half the mice ranged from 31 grams for Douglas fir to only 3 grams for Teflon.

Although experiments such as this may not be appealing to normal sensitivities, we must remember that people die from smoke, too, and it would be well for us to learn what produces the lethal components.

As a case in point, there was a fire in one room of Houston's Westchace Hilton Hotel in March of 1982. It was started by a careless smoker, but everyone in that room escaped without injury. As reported in the May issue of Science 83, however, twelve other victims in separate, undamaged rooms died from smoke inhalation.

Autopsies revealed that the deaths could not be attributed to CO, because only two of the victims revealed blood level contents approaching lethal amounts.

What was suspected as being the fatal factor was actually a mixture of ingredients--hydrogen cyanide (the same compound used in gas chambers) and hydrochloric acid. Above-normal cyanide levels were found in all the victims, although they reached clearly lethal levels in only two, both small children.

Hydrogen cyanide is produced when materials such as polyurethane and nylon burn--in other words, just about all of the decorations in a house, including nylon carpeting, blankets, carpet padding and chair cushions are potential contributors. Hydrochloric acid is released by burning or smoldering vinyl.

The various researchers admit that they do not have the final answers to the question of why more people succumb to smoke than to flames in house fires. This is all the better reason to provide your house with several smoke alarms, which will detect the fumes long before your nose does.