RESCUE GUIDLINES FOR AIR BAB-EQUIPPED VEHICLES
By James J. Onder
There still exists an unexpected concern in the emergency services community that air bag-equipped vehicles involved in crashes may be hazardous to rescue workers and victims. Information among rescue professionals significantly exaggerates the potential hazards of deployed and especially undeployed air bags during rescue operations. This could result in delays in assistance to victims of motor vehicle crashes.
The following guidelines will assist fire, EMS, and other public safety personnel who arrive on the scene of a crash in minimizing risks when extricating victims from air bag-equipped vehicles.
INCIDENTS WITH A DEPLOYED AIR BAG
Deployed air bags are not dangerous. They are not very hot or about to catch fire. Air bags deploy one time only and pose no danger after deployment.
If an air bag has deployed, you will see it drooping from the steering wheel, the dashboard, or the side of the driver`s and passenger`s seats. Rescue personnel who arrive immediately after air bag deployment will see smoke and powder inside the vehicle. The smoke is produced by the combustion of sodium azide and other chemicals within the inflator module.
The powder, usually corn starch or talcum, is used as a lubricant to ensure smooth deployment of the air bag by preventing it from sticking together while it is stored within the module. Also mixed with the residual powder is a small amount of sodium hydroxide, a by-product of combustion that takes place in the inflator module. This chemical is slightly alkali and may cause skin and eye irritation. When irrigated with water, sodium hydroxide becomes harmless baking soda. Some additional discomfort may be experienced if the powder gets into a cut or onto burned skin. Anyone who gets “the powder” on exposed body parts should wash with soap and water.
The actual burning process is contained within the inflator module and lasts for less than 110 of a second. The same gloves and eye protection that shield rescue personnel from sharp edges, glass, and bodily fluids also protect them from this powder.
INCIDENTS WITH AN UNDEPLOYED AIR BAG
Although it`s rare, an air bag can suddenly deploy during rescue operations, creating a hazardous operating condition and causing further injury and delay in medical assistance to victims. While every crash poses unique conditions, the following procedures will help minimize risks.
Identify the presence of undeployed air bags. Look for the words “Supplemental,” ” Inflatable,” “Restraint,” or “Air Bag” or the initials “SIR” “SRS,” or “SIPS” printed on the steering wheel hub, the instrument panel, the dashboard, the windshield, on or over the sun visor on the driver`s side B-post, or on the outboard side or back of the seat to determine whether the car is equipped with side air bags.
If you still can`t tell whether the vehicle has air bags, assume it has them, especially if the vehicle is a newer model.
Disconnect the power to the air bag system. Turn off the engine, and disconnect or cut both battery cables. Disconnect the negative cable first, followed by the positive. Make certain that the cables do not return or “spring back” to their original placement on the battery. Note: Move seats with occupants away from frontal air bags, if possible (considering possible in-juries), before disconnecting the battery in case the front seats are powered.
Should circumstances permit, disconnect or cut the negative battery cable near the engine block. During any disconnect, an arc will be created because there is always a current draw on the battery even when the ignition key is turned off. In addition, since the battery is going through discharge and generating some flammable hydrogen gas around the battery area, this can pose a problem. Keeping the arc away from the battery will help prevent the gas from being ignited.
In a severe crash, make certain the battery case has not been penetrated with metal body parts that could recomplete the electrical circuit. Battery disconnect can often be verified by attempting to turn on the headlamps and taillights. However, be aware that the impact of the crash may trip a circuit breaker or blow a fuse, causing the lights not to work.
Even after a battery disconnect, it is possible that static electricity can deploy the air bag. Static electricity can be generated by the use of hydraulic shears and rams, rescue personnel sliding across the seat, and the cutting of safety belts. After a crash, it is not possible to determine how much static electricity is present around the vehicle and, specifically, what wires individuals and extrication equipment may contact. Also, the use of rams and the prying open of body parts can trigger the deployment of mechanically activated side air bags. For these reasons, it is always best to treat air bag systems as if they were “live.”
If time permits, wait until the air bag system is deactivated. Check the Air Bag Deactivation Times chart on page 44 to find out how long it takes for the backup system to completely deactivate. Some vehicles may take up to 30 minutes to deactivate, but most vehicles take one minute or less. Although this will significantly lower the chance of accidental deployment, it does not make it 100 percent safe.
More importantly, rescue personnel must consider the need to reach and extricate victims as soon as possible and to reach a trauma center within the “Golden Hour” if they are to provide the best chance for victims to survive and recover to their fullest potential.
As an added precaution, perform extrication preparation efforts from the side of the occupants, through the roof, and away from the potential deployment path of the air bags.
Avoid placing yourself or equipment between undeployed air bags and the occupant.
Move seats with occupants away from frontal air bags, and lower the seat back if it is appropriate for the victim and type of injuries. When possible, tilt the steering wheel to provide additional clearance. Do this before disconnecting the battery in case the front seats are powered.
Do not drill or cut into the air bag module or apply heat above 350ºF in the area of the steering wheel, dashboard, or seat side panel.
Do not mechanically displace or cut through the steering column until the battery has been disconnected and all other rescue techniques have been performed and exhausted. On most air bag systems, cutting through the steering column should not cause the air bag to deploy. However, mechanical systems with the sensor built into the back of the air bag module are sensitive to sudden movement. Take painstaking care to provide a smooth continuous movement while using hydraulic rams and other displacement tools to move or cut the steering column. Be certain to have as much clearance as possible between the victim and the undeployed air bag before displacing or cutting the column.
Do not place anything over the air bag to try to hold it in or puncture the air bag to keep it from deploying.
Even after these procedures have been followed, emergency personnel should treat every undeployed air bag as if it were “live.”
INCIDENTS WITH A FIRE
An undeployed air bag is designed to inflate in a normal manner if the chemicals sealed inside the air bag module reach a temperature above 3507F. In case of a passenger compartment fire, the gas generators, after several minutes, may reach 3507F and ignite, causing the air bags to deploy.
Any effective firefighting medium, including water, can be used to extinguish fires. Use normal fire extinguishing procedures, and proceed with normal rescue guidelines. Cool the steering column, air bag module, and passenger side dash area for several minutes after initial fire knockdown.
IMPORTANT POINTS TO REMEMBER
Identify undeployed air bags. Look for air bags in the front, side, and, in some new vehicles, overhead positions. If you still can`t tell whether the vehicle has air bags, assume it has them.
Move seats with occupants away from frontal air bags. Do this before disconnecting the battery in case the front seats are powered. When possible, tilt the steering wheel to provide additional clearance.
Deactivate the air bag system by disconnecting the battery cables.
When time permits, wait for the proper deactivation time.
Stay out of the deployment path.
Never place equipment between the undeployed air bags and the occupant.
Do not place anything over the undeployed air bags to try to hold them in or puncture the air bag cover.
Wear gloves and eye protection such as those normally used by rescue personnel.
Use any effective firefighting medium, including water, to extinguish fires. Use normal fire extinguishing procedures, and proceed with normal rescue guidelines. Cool the steering column, air bag module, and passenger-side dash area for several minutes after the initial fire knockdown.
Treat every undeployed air bag as if it were “live.”
QUESTIONS FREQUENTLY ASKED BY EMERGENCY PERSONNEL
1. How does an air bag work?
When a frontal or near-frontal crash occurs at speeds comparable to a 10- to 14-mile-per-hour crash into a solid barrier, vehicle crash sensors trigger a chemical reaction inside the air bag module. This causes the frontal air bags to inflate. When crashing into movable barriers, the vehicle`s speed must be higher to get response from the sensors and to inflate the frontal air bags.
A moderate to severe side impact, or T-bone, will trigger that particular side air bag if the vehicle is so equipped.
The rapidly inflating bag splits open the cover on the steering wheel, dashboard, seat, or side panel and fully inflates to help protect the driver and/or passenger(s). This entire inflation sequence takes place in less than 110 of a second. Less than one second after inflation, the air bag begins to deflate automatically.
2. Is it safe to breathe the passenger compartment air after an air bag has deployed?
Yes. There have been no cases of acute or long-lasting respiratory distress reported by rescue workers who were exposed to air bag deployment by-products while attending to crash victims. There have been a few complaints of minor distress, such as brief coughing spells.
However, simulated tests were conducted with volunteers–chronic asthmatics–who were subjected to long-term exposure (20 minutes) to the atmosphere inside a vehicle, with the windows rolled up, after the driver and passenger-side air bags had deployed. In this type of environment, test results revealed that prolonged exposure to this atmosphere can cause significant asthmatic reactions in some people. Therefore, if a crash victim appears to be suffering from acute respiratory distress, rescue workers should consider the possibility of an asthmatic attack and treat the victim accordingly.
3. How does one deactivate mechanically operated side or frontal air bags?
Some 1995-1997 Volvos have side-impact air bags located in both front seats that are independent of each other and the frontal air bag system. All Volvos with side air bags display the letters “SIPS” on the windshield or on the plastic cover on the outboard side of the seat. Each side air bag is a self-contained mechanical, nonelectrical system. In a crash, the side-impact air bag will deploy if the seat panel receives sufficient pressure or a hard blow or if the door is closed and an object is between the door and seat. Therefore, avoid this type of contact with the seat during victim extrication.
Rescue workers can disarm the Volvo`s side air bag system by locating and cutting the black, ribbed cable running from the sensor`s unit to the air bag. It can be reached between the bottom and back cushions of the seat.
The side air bags in Mercedes-Benz vehicles are operated by the electrical system and are deactivated with the frontal air bags.
The Jaguar XJS model (up to model year 1995) has a mechanically activated frontal air bag system that can`t be deactivated in the field. Take extreme care to avoid sharp, jolting impacts to the steering column, and try to move the seat backward to aid in the extrication of the victim.
In 1997, BMW introduced an ITS system (Inflatable Tubular Structure) air bag in some vehicles. This is a form of side impact protection for the head. It is installed above the vehicle`s door frame and drops down (in a tube shape, diagonally crossing the window) when it deploys. This device will be deactivated with the other electrical air bag systems in the vehicle.
4. Is there still the potential for serious internal injuries?
Prior to the introduction of air bags and lap-shoulder belts, seriously injured occupants involved in crashes usually had visible signs of injuries (such as bleeding, facial lacerations, abrasions, bruises, and broken bones) that were obvious to rescue personnel. Now, occupants protected by these devices may not have as many of the previously visible injuries, but they still may need medical attention for the not-so-obvious or internal injuries.
After a crash, serious internal injuries may be present but may not be externally apparent. To address this situation and increase the chances that these crash occupants receive timely and appropriate emergency care, look beyond the obvious and encourage medical personnel to consider the possibility of internal injuries.
REPORT TO MEDICAL PERSONNEL
Collect and report to medical personnel circumstances surrounding the crash and potential internal injuries:
Steering wheel deformation. Lift the air bag and look for a bent steering wheel rim. This could indicate internal injuries.
Close proximity of the driver to the steering wheel. Occupants of small stature or large girth sitting close to the steering wheel are at greater risk of internal injuries.
Energy of the crash. Twenty or more inches of vehicle crush indicate high crash forces that can cause serious internal injuries.
Nonuse of seat belts. Nonuse of lap or lap/shoulder belts could result in multiple impacts and greater probability of internal injuries. Also, occupants who do not wear a seat belt but whose vehicle has an air bag will submarine under the air bag until their knees hit the knee bolster. Look for knee, leg, and hip injuries. Also, look for forearm bruising and fractures due to passengers` getting their arms between the deploying air bag and their forehead.
Eyewitness reports. Verbal reports and video images of the interior and exterior of the crash vehicle graphically convey the severity of the crash and can indicate the probability and type of internal trauma.
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Deployed air bags are not dangerous. They deploy only one time and pose no threat to rescue personnel. Undeployed air bags can be dangerous. As with other responses to a crash scene or a “nothing-showing” fire, complacency can injure. Knowledge, education, and experience are the answers. n
Modifications in air bags in newer-model vehicles will affect how fire service personnel extricate victims from their vehicles.
(Photo above left) The 1997 Cadillac DeVille, for example, is equipped with door-mounted, front-seat side air bags.
Six air bags are provided in the front-seat area in some of the more expensive models of the 1997 BMW. Two are in the front, two on the front side (photo above center), and two tubular air bags drop down from the ceiling to protect the head.
In some models of the 1997 Ford, the front seat has a head-thorax bag (photo right).
Also, the 1997 Audi A8 has six air bags: two in the front, two on the front side, and two on the side of the rear seat.
–JAMES J. ONDER
JAMES J. ONDER, Ph.D., is a highway safety specialist with the National Highway Traffic Safety Administration in Washington, D.C.