A Cautionary Tale

Two Dartmouth researchers say automobile air bags and airplanes' inflatable escape chutes that protect passengers may have a safety problem of their own. In a recent paper in Critical Reviews in Toxicology, the leading review journal on toxicity, DMS professor of pharmacology and toxicology Roger Smith and chemistry professor Dean Wilcox warn that the sodium azide propellant that inflates air bags and escape chutes with harmless nitrogen is a toxin that may endanger the workers who handle the canisters.

To date no cases of azide poisonings have involved air-bag or escapechute canisters. But there have been a handful of mishaps in biological or chemical laboratories, where workers have unwittingly ingested or inhaled azides that are commonly used as preservatives for organic compounds but not always adequately labeled. The consequences: headaches, nausea, heart palpitations, and other distresses, and, in some cases, death.

In addition to calling for stronger warning labels on azides used in labs, Smith and Wilcox urge greater safety measures for the workers who assemble and service air bags and for the demolitionists who dispose of old cars. The 60 grams of sodium azide in an air bag canister is enough to kill, the researchers warn. They also make the case for further research into the benefits and the hazards of azides. Says Smith, who has already spent 30 years studying the chemicals, "We have something in wide use, but we don't know all the consequences."

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