Southeast Toyota Distributors, LLC (“SET”) just announced an airbag recall that effects several models, including the popular 4Runner, Camry, Prius, Avalon, Corolla, FJ Cruiser, Highlander, RAV4, Sequoia, Sienna, Tacoma, Tundra, and Venza. According to the Recall, SET determined that the vehicles “may not” have had a standard sensor calibration test performed after installation of leather seat covers, set heaters, or headrest DVD entertainment devices.

Why should you care? The airbags may be rendered useless in an accident, or may actually cause an injury through deployment. These systems rely on sensors to determine when and how the air bags deploy. The speed of air bags at deployment are so fast, they can turn an otherwise survivable accident into a deadly one. Timing is everything –

You may have noticed that that guy moved back as far as he could, and tucked-in his lower lip. That air bag is coming at the occupant really…really…really…fast. Unlike that demonstration, during a crash, the occupant moves toward the steering wheel, and the deforming compartment moves toward the occupant, and the air bag moves toward the occupant. If the occupant and air bag meet at the wrong time, bad things happen. As National Highway Traffic Safety Administration explains:

Causes of Air Bag Fatalities

Several factors are common to air bag-induced fatalities. First, they involve air bags that do not meet the suppression or low risk deployment requirements of this rule. Second, the occupants are generally very close to an air bag module when the air bag begins to deploy during a crash. The one fact that is common to all persons who died is not their height, weight, gender, or age. Instead, it is the fact that they were very close to an air bag when it started to deploy. For some people, e.g., infants in rear-facing infant seats, this occurred because they were initially sitting very close to the air bag. For the other occupants, this typically occurred because they were not restrained by seat belts or child safety seats and moved forward during pre-crash braking.

Closeness is a problem because, in order for an air bag to cushion an occupant’s head, neck, chest and abdomen and keep the occupant from hitting the steering wheel, windshield or instrument panel, the air bag must move into place quickly. The force of a deploying air bag is greatest as the air bag begins to inflate. If occupants are very close to or in contact with the cover of an air bag that does not meet the low risk deployment requirements of this rule, they can be hit with enough force to cause serious injury or death when the air bag begins to inflate. This can be caused either by the cover as the air bag breaks out of the module (known as the “punch-out” effect) or by the unfolding and inflating air bag as it first conforms to the contours of the occupant and then moves rapidly into its fully-inflated shape (known as the “membrane” effect).

In all of the 92 SCI confirmed fatalities involving children, the children were very close to the instrument panel when the air bag deployed. Because of their proximity, the children sustained fatal head or neck injuries from the deploying passenger air bag.

Eighteen fatally-injured infants were close to the air bag because they were in rear-facing infant seats installed directly in front of a passenger air bag. A rear-facing infant seat which is installed in the front seat of a vehicle with a passenger air bag will almost always position the infant’s head very close to the passenger air bag. Several other infants were being held in the lap of a passenger.

All but a few of the 74 fatally-injured older children were not using any type of restraint. Of those who were restrained, most were not correctly restrained. The non-use or improper use of occupant restraints allowed the vast majority of these children to move forward during preimpact braking before the actual crash. As a result, they were very close to the air bag when it deployed.

As in the case of the children fatally injured by air bags, the key factor regarding the confirmed deaths of adults has been their closeness to the air bag when it deployed. The most common factor that allowed them to become very close to the air bag was the failure to use seat belts. Only 18 of the 60 drivers are known to have been properly restrained by lap and shoulder belts at the time of the crash. (49 CFR Parts 552, 571, 585 and 595.)

If you own or lease a vehicle that is affected by this recall, you can contact NHTSA at 1 (888) 327-4236 (TTY 1 (800) 424-9153), or SET at 1 (800) 301-6859.