Lately, we have received numerous calls and emails about airbags causing breathing difficulties.  Most people wonder whether airbag deployment has been linked to such problems, especially when someone already has asthma or other conditions that affect breathing and respiration.

The answer is clearly YES. 

The automotive industry has known for many, many years that air bag deployment can cause breathing problems, and that those problems can be especially severe when a person has pre-existing respiratory conditions.  Here’s why:

Air bag deployment is often based on the burning of chemicals.  The most widely used chemical is sodium azide.  When it burns, it generates not only nitrogen gas that fills the airbag, but also numerous by-products.  In this way, it is similar to the burning of gas in your engine creating numerous by-products that come out of your exhaust system.  Although other airbag inflators may use stored gas, they also have a “heating element”, which means another chemical that is burned to heat and expand the gas that inflates the airbag.  Because no combustion is 100% pure, there are always by-products produced by all of these inflators.

The by-products fall within two broad categories: gases and particulates.  Gases that are produced can include those that have been linked to severe injuries, such as benzene and toluene.  Particulates are small particles that are suspended in the air, which appear as smoke or dust.  They are the reason that many people report seeing smoke in their car after an airbag deploys.  This is because all airbags have venting, either through the porous fabric or through vent holes, that allow the smoke to escape from the airbag, as seen in this photo:

Collectively, gases and particulates from an air bag are called “effluent”, which simply means they flow out from the air bag during deployment.

The concerns over the harm that could be caused by these airbag chemicals led the Society of Automotive Engineers to create a standard for measuring these by-products.  That standard lists numerous chemicals that should be measured by the manufacturers to determine the risk of injury posed by their inflators.

More than a decade ago, General Motors conducted tests to evaluate the effects of these chemicals on people exposed to air bag deployment.  I know, since I personally saw such testing.  I provided a car for the testing, as well as many air bag modules, and the testing was conducted by scientists at the General Motors Research Laboratories.  The results were astounding.

Volunteers were used for such testing.  They sat in the back seat of the car, with medical professionals supervising the testing.  There were also numerous instruments in the vehicle to measure the amount of gases and particulates, as well as their types and sizes.  The intent was to have the volunteer stay in the car, with the windows up, for 20 minutes following deployment.  During that period of time, the volunteers’ physiological signs were monitored, including their breathing rate.  In at least one case, the volunteer could not stand it, and needed to get out of the car almost right away.  His measurements showed significant distress!

That testing also showed that the most vulnerable people were those who had other, pre-existing conditions affecting their ability to breathe.  For example, people with asthma were at risk.  The more severe the asthma, the higher the risk from air bag deployment.  Several people have reported very significant respiratory injuries from airbag deployment; we have even heard of one death attributed to air bag deployment.  The worst injuries occur if a person cannot exit the vehicle right away (for example, if they are knocked out, or if the doors won’t open after the accident), and the windows are closed.

That same testing program also evaluated the effect of air bag deployment on a person’s hearing.  That will be the subject of a separate post.

Toyota is recalling 133 model year 2004-2006 Lexus LS, 2006 Lexus GS, 2006 Lexus IS, 2004-2006 Toyota Prius, 2005 Toyota RAV4, 2005-2006 Toyota Tacoma, 2005-2006 Scion TC, 2005-2006 Toyota Avalon and 2007 Toyota Camry vehicles. On certain vehicles, due to improper assembly of the air bag inflator, which is used in the side air bag, the curtain shield air bag, and the knee air bag assembly, some inflators were produced with an insufficient amount of the heating agents necessary for proper air bag deployment.

In this condition, the expansion force of the gas may be insufficient to properly inflate the air bag when the SRS system is activated during a crash. This may increase the risk of injury to the occupant in the involved seating position in the event of a crash. Dealers will replace the specific SRS air bag. The recall began on April 6, 2006. 06V-096.

This is yet another recall that indicates that Toyota’s quality control measures were inadequate for such a critical safety component.  Simply put, safety related parts like air bag should never be shipped from the manufacturing facility if they do not meet specifications.  That is the whole purpose of a quality control program: to ensure defective parts never make it to the consumer.  Obviously, the quality control system failed, unnecessarily exposing Toyota customers to the risk of serious injury or death.

Honda is recalling 34,300 model year 2007-2008 Honda Fit vehicles originally sold in or currently registered in the states of Connecticut, Delaware, Illinois, Indiana, Iowa, Kentucky, Maine, Maryland, Massachusetts, Michigan, Minnesota, Missouri, New Hampshire, New Jersey, New York, Ohio, Pennsylvania, Rhode Island, Vermont, Virginia, West Virginia, Wisconsin and the District of Columbia.

The wire harness for the occupant detection system (ODS) and the occupant position detection system (OPDS) is routed underneath the carpet on the driver’s side floorboard. In areas where road salt is used, salt from the snow on the driver’s shoes will melt and may penetrate the carpet and leak into the wire harness. If the harness is exposed to salt brine, corrosion may occur and the wire may break causing the SRS indicator light to illuminate.

A failure of the ODS and OPDS may not detect the presence of a child seat or an out-of-position passenger and deployment of both the front seat passenger’s frontal and side air bags will not be suppressed. In the event of a crash, a deploying front passenger air bag or front passenger’s side air bag will increase the risk of injury to small or out-of-position occupants.

Dealers will inspect and replace the wire harness. The recall is expected to begin during January 2008. 07V-549.

Land Rover is recalling 37,142 model year 2005-2006 Land Rover LR3 and Land Rover Range Rover Sport vehicles. Relative motion between the steering wheel hub and/or the steering column cowl with the clockspring, which includes the driver side air bag circuitry, could result in fracturing of the air bag wiring connection.

If an air bag wire fractures, the SRS warning light will illuminate on the instrument cluster. The SRS warning light indicates to the driver that there is a concern with the SRS system in the vehicle and that immediate repair is necessary. If the SRS warning light is ignored and a vehicle crash of sufficient severity to command deployment of the driver’s air bag occurs, the air bag module may not deploy in the intended manner.

The condition may result in the deployment of only one stage of the dual stage driver’s air bag or the air bag may not deploy at all increasing the risk of serious injuries to the driver. The recall is expected to begin on or about July 21, 2008. 08V-248.

General Motors Corp. (GM) is recalling 79 model year 2009 Chevrolet Impala vehicles.  Internall at GM, these Chevrolet Impala cars are part of the W-car platform.  Some of these vehicles have a passenger-side front air bag inflator that could fracture at an inflator tube during a deployment.

This is because some inflators were improperly manufactured with two secondary inflator filter discs, rather than just the one that was specified.  Using two discs can cause the pressure to back up as a result of gas flow blockage.  During a passenger-side air bag deployment, pieces of the inflator tube could strike and injure vehicle occupants and the air bag cushion would not inflate fully, reducing the capability of the bag to protect the passenger. The recall is expected to begin during mid-October 2008. 08V-517.

This defect was discovered during quality control (lot acceptance) testing at the supplier’s plant.  This recall proves that GM’s and the supplier’s quality control procedures were not working properly.  The defective parts should never have been shipped from the supplier’s facility until after all the quality control tests had been passed.  Instead, it seems that the supplier decided to ship the parts to GM for installation on cars before it had confirmed the tests were passed.  This unnecessarily puts GM’s customers at risk for this safety defect.

Mazda is recalling 213,000 model year 1995-1996 Mazda MX-6 and 1995-1997 Mazda 626 vehicles.  These vehicles can experience air bag deployments in minor undercarriage impacts. Unexpected air bag deployment can result in occupant injury.

Dealers will reprogram the SAS unit to reduce the probability of unnecessary deployments in low speed undercarriage impacts. Owner notification was expected to begin during January 1999. 98V-249.

This safety defect recall affecting many Mazda vehicles shows two problems that occur fairly frequently among many car companies.  First is the over-reliance on electronic single-point sensors.  These sensors are essentially mini-computers that are located in the passenger cabin, far away from the front crush zone that is deformed in a frontal crash.  Because they are so far away, they are often designed with a hair-trigger, in order to be able to sense the frontal crash from so far back in the car.  This hair-trigger causes these sensors to mistakenly predict a severe crash is taking place, when in actuality there is no such severe crash.  It is thus not surprising this type of electronic single-point sensor can result in unwarranted and unjustified airbag deployments, which can themselves cause injury to consumers.

Often, car companies decided to use electronic single-point crash safety sensors to save money.  For example, the recall above affected the 1995 through 1997 model years of the Mazda 626, which used the electronic single-point sensor.  However, the 1994 model year was not affected by the recall.  This is because the 1994 model year used three separate airbag sensors located in the front of the car. 

Mazda 626 Airbag Crash Sensor Changes

Because they were in the front crush zone, they did not need to be designed with a hair-trigger, and were thus less vulnerable to mis-judging minor impacts.  They were also much less likely to deploy the airbags in undercarriage impacts.  Using the single electronic sensor was cheaper than using the three separate sensors in the front of the car.  A company should never put profits ahead of safety.

The second problem is that many car companies have taken shortcuts in designing and developing their airbag systems.  Rather than testing their air bag sensor for all reasonably foreseeable types of crashes, they cut corners.  This elimination of certain tests can result in airbag deployment in such crashes, even when such deployment should not occur.  Simply put, pinching pennies during the design and development process can result in severe injuries to consumers.  Unexpected deployments can also actually cause a crash when they unexpectedly startle a consumer.