The Hidden Hazards of Airbags

(NHTSA) those have been almost completely eliminated, now that the public understands the need for seating children in the rear seats of vehicles, away from the airbags. However, the other injuries to drivers and front seat passengers have largely been ignored, since it is estimated that over 28,000 lives have been saved as of 2009 by using airbags.

The rapid deployment of the airbag at speeds greater than 100 mph has caused broken bones and skin abrasions. Around 2.5% of all drivers in crashes are likely to suffer serious injury as a result of airbag deployment, according to Craig Newgard, from Oregon Health & Science University, who researched statistics on 1995–2005 crashes. Burns to faces and arms, coughing fits, and asthma attacks are other common injuries during airbag deployment, according to the Automotive Occupant Restraints Council (AORC).

The hazards of airbags are not being ignored by OSHA, the Occupational Safety and Hazard Administration, the watchdog for worker’s safety. They began issuing guidelines in 2001 for emergency responders that include cautions against breathing in the contents of the passenger compartment of cars where airbags have been deployed and warning against touching the steering column due to the heat of the chemical reaction that inflates the airbag. Undeployed airbags at crash sites are also a hazard for emergency personnel if they inflate unexpectedly while the accident victim is being extracted from the car, warns OSHA.

All emergency responders are now trained to deactivate undeployed airbags before treating patients in the car as advised by training groups such as Midsouth Rescue Technologies, a non-profit Fire and Rescue Training Organization.According to Washington University’s department of chemistry, sodium azide, NaN₃, is the most common propellant for the airbag. When a crash occurs the azide is ignited and it decomposes to produce nitrogen gas, N₂, which fills the airbag (2NaN₃à 2Na + 3N₂) in .025 seconds at speeds between 150 and 200 miles per hour. Extreme heat is also given off by the exothermic reaction of the sodium azide as it ignites

Sodium hydroxide, a caustic powder, is one of the by-products of the reaction. It is generated because potassium nitrate, KNO_3, is placed in the detonator canister with the azide to scavenge sodium formed during the explosion. Sodium metal is extremely reactive, and can actually causing unwanted explosions with water (2Na + 2H₂O –> 2NaOH + H₂). The heat given off when sodium metal reacts with water is sufficient to ignite and explode the hydrogen gas produced. 

Sodium hydroxide is often found in the gas fumes that escape from the airbag as it deflates. Although in only small amounts, the NHTSA has found that sodium hydroxide is causing coughing fits and asthma attacks in the drivers and passengers. Rescue workers are advised to wear gloves and safety glasses and to completely ventilate the car for several minutes before entering. The excessive coughing caused by the air bag powder can also make a chest injury worse.

Emergency personnel are now treating all accidents with airbag deployments as potential brain, chest and spine damage, according to Midsouth Rescue Technologies. Also, according to the AORC, the recommended hand position on steering wheels has changed from ten and two to nine and three o’clock in order to avoid damage to the radius and ulna, the bones in the arm and also to prevent the arm from damaging the face after it is hit by the airbag.

Others, such as University of Arizona researcher, Eric Betterton, are concerned that sodium azide will escape from the container and get into the environment. Sodium azide is an extremely toxic poison, capable of destroying entire ecosystems. An undeployed airbag contains between 50 grams for the driver side and 200 grams for the passenger side. After the airbag reacts, all of the sodium azide should be converted to harmless nitrogen gas. Undeployed airbags should be removed from cars before they are “junked” or put into landfills in order to prevent unreacted sodium azide from getting into the environment, recommends Betterton.

New types of airbags have been appearing since 1998, such as the side impact airbag and the dual depth system. Inflators using compressed nitrogen or argon gas have been replacing the sodium azide, according to Midsouth Rescue Technologies. Airbags are now being tested using crash dummies that simulate young children and smaller female passengers, instead of the previous practice of just a 5’8”, 180-pound male adult.

So how does Teresa feel about airbags? “I wouldn’t drive in a car without them. We all walked away with no broken bones while the van was totaled.”