The collision-deployed airbag is a passive restraint device intended to protect the driver and/or passengers in a car during a collision. Driver's side airbags have been required in new cars in the United States since 1994. Passenger side airbags have been required since 1998. While airbags have saved many lives, a small number of people have been killed or injured because of them.
How the Airbag Works
Every car equipped with an airbag has a control unit consisting of sensors and a small computer that determines if circumstances have reached the threshold necessary for airbag deployment. The sensors measure changes in the car's velocity, the speed of the wheels, the pressure encountered by body panels and the orientation of the car. The control unit also senses how many occupants are present and if they are wearing their seat belts.
During a collision, the airbag control unit inflates the airbag with a chemical propellant, causing the bag to deploy in less than five one-hundredths of a second. It also tightens the seat belts, and if an occupant is not wearing a seat belt, adjusts the pressure of the airbag deployment to compensate for this. Immediately after the collision, the airbag deflates. It is a one-use item and must be replaced if it has deployed for any reason.
General Airbag Injuries
While the violent deployment of an airbag is far preferable to enduring a collision without an airbag, there are certain risks and injuries that are commonly caused by the airbag. The propellant used to inflate the bag combusts explosively when the airbag is inflated. This combustion can cause burns to the chest, neck, face, and arms of the occupant. The propellant can also cause respiratory and eye irritation. The force of the airbag deployment will abrade or bruise the skin, and the noise from the deployment can cause hearing loss. According to MedScape, when the occupant has braced themselves against the airbag panel, the deployment can break bones in the hand, wrist and arm.
Airbag Chest Injuries
Generally speaking, occupants restrained by a seat belt and airbag are far less likely to be injured or killed in a collision. However, some rare chest injuries have occurred. Non-fatal injuries also included rib fractures, sternum fractures and bruising, the heart, and lungs, the rupture of the aorta, pneumonia and a heart attack. The National Institutes of Health published several papers that document a handful of fatalities were caused by airbags and involved extensive rib fractures, severe bruising within the chest cavity, and cuts and punctures of the heart and its surrounding membranes.
Causes of Chest Trauma
In both published fatal injuries, the driver was significantly below average height and sat less than ten inches from the steering wheel, causing the airbag to transmit the full force of its deployment to the driver's chest. In some circumstances, the occupant was slumped forward due to previous injury or unconsciousness, putting them in the path of the airbag. Injuries such as pneumonia and heart attack, while noteworthy, appear to be singular episodes caused by chance or startling bad luck.
The National Highway Transportation Safety Administration publishes guidelines applicable to all occupants of airbag-equipped vehicles. Always wear the seat belt provided by the car manufacturer. In the front seat, always use both the shoulder and lap belt. Sit at least ten inches (25cm) back from the steering wheel or dashboard. Children younger than 12 should ride in the back seat. Under no circumstance should a rear-facing infant seat be placed where there is an active airbag.
If you have a condition or circumstance which prevents you from following these guidelines, you should determine if your car has a deactivation switch for the airbags and turn the airbags off.