GM Says Some Rivals’ Side Air Bags Pose Risk

General Motors Corp. said Thursday that its testing revealed some competitors’ side air bags could seriously injure or kill children who are leaning against them during a crash--a finding rival auto makers immediately questioned.

GM’s videotapes of the tests show the neck of a small test dummy being snapped forward violently as an air bag deploys. 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 own Chevrolet Venture minivan showed its side air bags deploying 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 it determined pose a threat in its announcement during the Chicago Auto Show. “We’re not interested in poking our competition in the eye,” said Robert C. Lange, director of GM’s safety center near Detroit.

Several auto makers have introduced side air bags on some of their models recently.

While side air bags can reduce the risk of head, chest and pelvic injuries to properly seated and belted adults, there are no government regulations to guide auto makers on how forceful side air bags should be to limit potential injury to children.