At least once a month for years, we have gotten calls from someone complaining about malfunction of an airbag in a motor vehicle collision. Usually it is a matter of an airbag not deploying in a situation in which it was never designed to deploy.

Most front airbags are designed to deploy in a direct frontal impact, and side air bags are generally designed to deploy in direct side impact. There are variations between models as to whether an oblique angle impact would cause an airbag to deploy, but generally a sideswipe collision will not activate an airbag.

Moreover, most people making those calls are upset but no one had a catastrophic injury in the wreck. The expense and difficulty of automotive product liability litigation is such that the cost-benefit analysis seldom justifies filing suit unless there is a death or catastrophic injury.

But now there is a widespread problem with airbags in a wide variety of vehicles deploying when they should not, potentially causing serious injuries to vehicle occupants.

Since 2008, there have been six rounds of recalls- the most recent involves 7.8 million vehicles, more than 100 models and 10 manufacturers, and focuses on vehicles equipped with defective airbags made by a Japanese supplier, Takata.  The National Highway Traffic Safety Administration (NHTSA) urges all owners of cars listed on the recall to get their airbags fixed immediately.

                “The airbags are made by Japenese supplier Takata. The bags have faulty inflators than can rupture and send metal fragments flying out. At least four people have died in accidents related to the defect. A hot climate appears to trigger airbag failures, so the recalls are considered especially urgent for people living in Florida, Hawaii, and U.S. territories.”

Safety advocates say at least four people have died from the problem and there have been multiple injuries. They also say more than 20 million vehicles in the U.S. are equipped with the faulty air bags. Takata knowledge of the defect, reportedly, goes back to at least 2004 when Honda, the first manufacturer to launch a recall, received the first injury claim from an exploding “inflator” and reported it to the supplier.

The NHTSA warned people whose cars have been recalled during the past two years for faulty air bag inflators to take them to dealers right away. The inflators are made by Takata Corp., a Tokyo-based supplier of seat belts, air bags, steering wheels and other auto parts. So far, automakers have recalled about 12 million vehicles worldwide because of the problem.

“This message comes with urgency,” NHTSA said in a statement. The agency has been investigating the problem since June, and has cited reports of six inflators rupturing, causing three injuries.

Passenger or driver air bags or both could be affected depending on the vehicle. Toyota issues the latest recall Monday, covering passenger air bags in 247,000 older model vehicles including the Lexus SC, Corolla, Matrix, Sequoia and Tundra.

Like many of the other recalls, the Toyota recall includes areas that have high absolute humidity – south Florida, Puerto Rico, Guam, and the Virgin Islands to name a few. Toyota in documents posted to the NHTSA website, said the company and Takata are still trying to pinpoint the cause of the rupture and to gauge the influence of high absolute humidity.

Absolute humidity is a measurement of water vapor in the air, while relative humidity, which is commonly in weather reports, measures air moisture content relative to the air temperature.

Toyota has been testing the air bags, and it found an unusually high incidence of inflator failures along the coasts, according to spokesman John Hanson. The investigation continues and the recall could be expanded to more areas, Hanson said.

Toyota says it knows of no crashes or injuries from the cars it has recalled. Neither Toyota nor NHTSA could say exactly how far inland the recall area goes or what states it covers.

Last week, two U.S. senators questioned why the safety agency is allowing the recalls to be done on a regional basis because cars could be driven to, or people could move to the high-humidity states.

They also cited the May 27, 2009, death of 18-year-old Ashley Parham of Oklahoma City. She was driving a 2001 Honda Accord across a high school parking lot in Midwest City, Oklahoma, when it hit another car. The air bag inflated and sent shards of metal into her neck, causing her death.

“Based on NHTSA’s open investigation, the agency will take appropriate action, including expanding the scope of the recall if warranted,” an agency statement said.

Takata has said it recognizes the critical role that government plays in public safety, and it is supporting safety regulators.

“Takata identified two processes that, taken together, could have resulted in elevated moisture levels in the propellant. Elevates propellant moisture levels, when coupled with thermal cycling in automoviles, could cause the propellant density to decline over time and such a decline in density could lead to overly energetic combustion during deployment of the air bag.”

However, Takata’s claims that the problem was confined to problems of one particular propellant machine that compressed a powder mixture into a tablet, during a brief, discrete period of time, have proven to be false.

Takata also claimed that no manufacturer other than Honda would be affected even though the propellant chemistry had been used in over 100 million airbags over the previous decade. Takata claimed Honda’s inflator design was not significantly similar to that of other Original Equipment Manufacturers (OEMs) for which Takata supplied airbags. Takata reported to the NHTSA that a small number of bags, produced for another unidentified manufacturer during that time could not be defective because they had a different production process and better control systems.

In a statement made on February 19, 2010 Takata upheld that the problem had been fixed due to its “continuous improvement policy,” involving “numerous process improvements during this period, many of which improved the quality of the propellant and the inflators and enhanced the consistency of inflator performance.”

Faulty recordkeeping and poor recall notification procedures are other factors advancing the death and injury count. In numerous reports to NHTSA, Honda identified different impediments to identifying the correct recall population, ranging from confusion over which components and processes were confirmed as being within regulation, to a failure to trace defective airbags used as replacement parts.

Ken Shigley is an Atlanta-based personal injury and wrongful death trial lawyer. He is past president of the State Bar of Georgia, chair-elect of the American Association for Justice Motor Vehicle Collision, Highway & Premises Liability Section, and a board certified civil trial attorney of the National Board of Trial Advocacy.