CHICAGO -- General Motors Corp.'s testing revealed some competitors' side air bags could seriously injure or kill children who are leaning against them during a crash, the world's largest automaker said Thursday.
The findings were immediately questioned by rival automakers.
GM's videotapes of the tests show the neck of a small test dummy being snapped forward violently as an air bag was deployed. The dummy representing a 3-year-old was positioned as if it were a child sleeping against the door.
Tape of the same test on GM's Chevrolet Venture minivan showed its side air bags deployed more gently. While GM's side air bags are as powerful as others, they allow some of the air to escape through vents if someone is seated too close.
The technology relies on simple physics: As the air bag deploys, its extreme force is initially tempered by the door panel. If there is the pressure of a body against the panel, more of the air is deflected through the vents in the bag, slowing the force even more.
GM did not identify whose air bags pose a threat. "We're not interested in poking our competition in the eye," said Robert C. Lange, director of GM's safety center near Detroit.
But the announcement during the Chicago Auto Show's media preview was immediately questioned by automakers who have led the industry in offering side air bags.
"We've had three years of experience with this technology and we have not had a report of that sort of injury," said spokesman Steven Rossi of Mercedes-Benz of North America Inc. "We've put it through exhaustive testing and have not had any surprising results."
Rob Mitchell, a spokesman for another German automaker, BMW, said passengers are better off in a car with air bags than without. "The risk of injury from an air bag is nothing near the risk of injury from an accident," he said.
While side air bags can reduce the risk of head, chest and pelvis injuries to properly seated and belted adults, there are no government regulations to guide automakers on how forceful side air bags should be to limit potential injury to children.
The National Highway Traffic Safety Administration recently asked automakers to thoroughly test side air bags with adult and child dummies in a variety of positions to determine the risk of serious injury.
"Young children, with their less developed bones and muscles, are at a greater risk of injury from some competitors' side air bags than GM's," said Norm Pilcher, chief engineer for the Chevrolet Venture.
Safety features have become a major selling point for automakers in the 1990s, a reversal of the decades-long conventional wisdom in Detroit that "safety doesn't sell."
Ford Motor Co. has heavily promoted the government crash-test ratings of its Windstar minivan.
Last month Ford announced it had developed a system that will use a two-stage air bag linked to a computer to sense the car's speed, the weight and position of the driver and passengers, and the severity of the crash. In less severe crashes, the air bags will deploy less forcefully.
GM's Lange said Ford's system will use a seat sensor system that it rejected. GM will make its testing procedures and data, as well as its air bag technology, available to other automakers, said Bill Kemp, legal affairs director for the GM car group.
While front air bags have been blamed on the deaths of at least 69 children and 56 adults since 1990, they have saved an estimated 3,800 lives. There have been no documented deaths yet from side air bags, which have just entered the market in the last two years.
Besides Mercedes-Benz, BMW and Ford, several other automakers have introduced side air bags on some models recently. GM offers side air bags standard on its Chevy, Oldsmobile and Pontiac minivans, the Cadillac Seville and DeVille, and as an option on the subcompact Chevrolet Prizm.
Most manufacturers offering side air bags, including GM, provide them to protect the driver and front-seat passenger only. Only a few also offer rear-seat air bags. All automakers and the government recommend that children under 12 always be seated with belts in the back seat to protect them from potential injury from front and side air bags.
GM North American President Ronald Zarrella also announced the automaker will introduce a system to automatically detect when a small child is seated in the front passenger seat and disable the passenger front air bag. The system will be available first on the mid-2000 Seville and eventually will be used across GM's product line, Lange said.
The system uses a fabric mat in the seat cushion that measures the weight and pressure distribution on the seat to determine if it's a child or child-safety seat.
In 1997, automakers reduced the force of air bags in response to the deaths of dozens of children and small adults in "modest crashes" that would not have been fatal if not for the air bags. But Lange said reducing the force any further to fully protect children would not allow enough protection for adults, so the only truly safe alternative is an automatic shutoff device.