WASHINGTON - When it began to be clear from a rash of deaths in 1995-96 that airbags posed a serious threat to children and infants, Dr. Ricardo Martinez admits he was caught short by a lack of scientific understanding of how the safety devices had become killers.
That information blank spot will not be repeated as the industry begins to deploy reduced-force airbags on new cars and trucks, the head of the National Highway Traffic Safety Administration vowed in a recent interview.
In fact, he said, NHTSA plans to send an accident investigation team to every incident in which a lower-powered airbag deploys -regardless of whether anyone is killed or injured - to study what happened.
'What we are planning to do with depowered airbags is really investigate them as deployments occur early on,' Martinez said.
'We want to understand what the true outcome of these things (is). That is, we want to find to what extent some motorists will be in greater danger in severe crashes because the less forceful bags have been installed to prevent injuries and deaths to children and small adults in minor accidents.'
The disclosure that NHTSA will rigorously monitor depowered airbag performance demonstrates the uncertainty still surrounding agency efforts to overcome airbag problems.
It also serves as a reminder of how unprepared safety experts were for the rash of airbag injuries and deaths that began almost two years ago.
As Martinez recounted in his interview, NHTSA was aware in summer 1995 of scattered reports of airbag-caused injuries and had formed a team of researchers to look into the matter.
After 1996 model vehicles - the first to be widely equipped with passenger-side airbags - began reaching consumers in large numbers, the horror stories mounted. Newspapers and news programs jumped on the story of children and infants dying from airbag deployments, many in low-speed, single-vehicle mishaps.
NHTSA responded by issuing a warning to the public in October 1995, asking for expert comment on the issue in November and outlining a plan of action in January 1996.
Martinez said the agency needed relatively simple information on what was causing the deaths and how they could be prevented. But, he said, he was disappointed in the responses, especially from industry.
'No one could even tell us why kids were dying,' said Martinez, a former emergency room physician and specialist in trauma medicine.
In many cases, he said, studies showed that children were being killed not from the bag's direct head-on force, but from the so-called 'membrane effect.'
In this phenomenon, the deploying bag first envelops the child's face and neck. Then, as the bag finishes inflating, its surface snaps taut with enough force to violently force a child's head up and backward, causing neck and spinal trauma.
'It was not a well understood phenomenon,' Martinez said.
EFFECTS ON CHILDREN
The lack of understanding about the membrane effect was compounded by a lack of data about what happens to children in crashes, he said. NHTSA has never certified a child-sized crash-test dummy and there is a societal taboo against using child cadavers in research, he noted.
'One of the great black holes we have out there, had out there, still have out there, is kids. Because, as much as we hate to see children injured, there's nobody wants to do research on kids,' he said.
While there was considerable public clamoring for quick action, Martinez said he decided the agency had to come up with a comprehensive plan to deal with short-term and long-term problems and not create more hazards than it corrected.
After more months of research and debate, the plan unfolded early this year. The agency issued a rule to allow installation of depowered bags in new vehicles and said it would soon make rules on advanced airbags that could react differently to a variety of occupants and crash conditions.
The last and most controversial item is still under consideration at NHTSA - whether to allow widespread deactivation of airbags. (See story below.)
TWO CAUSES OF INJURIES
Not everyone has the same recollection of the airbag drama, however.
Mick Scherba, director of safety integration at General Motors, said industry safety experts knew before Martinez's call for help in fall 1995 that two separate mechanisms can cause airbag-related injuries and deaths.
One is called punch-out for the force that hits the chest or head of a person too close to a deploying airbag. The other is the membrane loading effect described by Martinez.
Scherba maintained industry engineers reported their findings in technical journals and had kept NHTSA's technical staff aware of membrane loading.
Nevertheless, he agreed that when he described membrane loading in a meeting with Martinez in late 1995, it appeared to be news to the administrator.
He also pointed out the industry does extensive safety testing and research with child-sized dummies, even though they are not certified by NHTSA.