Air Bag Noise
A letter from Elliot Berger of EAR to interested parties
Back to Air Bags
To: Interested Parties
From: Elliott H. Berger
Date: November 14, 2000
Re: Airbags: Auditory Risk and Issues of General Effectiveness
I continue to hear from many motorists and researchers who share
stories about the failure of airbags to protect occupants, and the
auditory and other injuries they cause. Unfortunately in a country that is
quick to react to apparent corporate malfeasance, such as the cause of the
100 lives lost due to Firestone tire failures, for some reason the airbag
situation which has cost equally as many lives and even more hearing
accidents fails to make the radar screens. Here are some of the facts and
resources I have been able to assemble.
In February 1997 the American Academy of Otolaryngology - Head and Neck
Surgery (AAO/HNS) wrote to the National Highway Traffic Safety
Administration (NHTSA) urging NHTSA to "consider the heath aspects of
hearing damage from the noise and pressure of airbag deployment."
- Warning labels in automobiles about the loudness of the blast of
- Consumer education
- On/off switches on all driver and passenger airbags
In March 1997 the National Hearing Conservation Association (NHCA) wrote
to NHTSA urging tham to consider the auditory risks of airbag deployment.
- Allowing deactivation of both driver and passenger airbags
- Requiring the installation of on/off switches for both driver and
- Warning labels in automobiles about the loudness of the blast of
- Designing airbags that deploy with less force and noise
NHTSA ignored the information (cited above) which was provided by two
leading professional organizations involved in hearing conservation. In
the final report of the NHTSA-sponsored "National Conference on
Medical Indications for Air Bag Disconnection: (July, 1997) their medical
the phenomenon of hearing loss has not been noted to occur
due to airbags. The specific conditions of hyperacusis and tinnitus are
not associated with hearing loss, and persons with these conditions would
have no greater likelihood of hearing loss from air bag deployment than
any other persons."
In 1998, a special session was organized for the October meeting of the
Acoustical Society of America with five invited papers of the topic
Acoustical Effects of Airbag Deployment. The salient issues reported in
that session were:
- More than 100 cases of individuals suffering permanent hearing loss,
hyperacusis (painful over sensibility to noise), tinnitus, and
disequilibrium (balance disorders) are published in the literature in
spite of the fact that there is no means of formally reporting auditory
injuries from airbag deployments and no concerted research efforts.
- Theoretical predictions based on a mathematical model of auditory
hazard, confirmed by comparison with both animal and human experiments,
show that under certain conditions it is likely that >90% of
individuals will be at risk for hearing disorders when exposed to
current airbags (open windows, unanticipated deployments, head turned so
that ear is facing the airbag). Under the best case conditions the risk
will range from <1% to a few percent. The theory also suggested that
the auditory hazard could be materially reduced while maintaining other
dimensions of airbag performance. [Dick Price, auditory
psychophysiologist, US Army.]
- NHTSA's panel is categorically incorrect in stating that hearing loss
has not been noted to occur due to airbags, that tinnitus is not
associated with hearing loss, and that those with hyperacusis or
tinnitus are not at greater risk.
As a result, in part, of the above mentioned session, in September 1999
the Acoustical Society of America (ASA) wrote to NHTSA urging them to
amend their current position regarding airbags. They recommended:
- Acknowledging that airbag deployment can cause hearing loss,
tinnitus, hyperacusis and balance disorders
- Developing a data collection system to properly quantify the risks
vs. benefit of airbag deployment
- Educating the public about the potential damage to hearing and
balance from a 160- to 170-dB airbag impulse
- Studying criteria for deactivation options
- Including warning labels to accurately indicate the risks of airbags
Many are concerned that deactivating the airbag to avoid auditory risk
is too hazardous because airbags "are so effective." The actual
facts, according to Leonard Evans, an internationally recognized traffic
safety research, previously employed by GM and currently the President of
the International Traffic Medicine Association:
"The three best technical studies consistently find that airbags
reduce the risk of death in a crash by 9% for belted drivers."
Evans goes on to state that the current claim by NHTSA is that airbags
have saved about 1,700 lives, but this is only an inference calculated
from estimated effectiveness. Balance this against the 62 individuals who
were killed by airbags in crashes that, without the airbag, were unlikely
to injure (Note that number is higher today - 158 cases). Some of those
were accidental deployments in which the airbag should not have inflated
at all, such as 28 reported cases wherein the airbag discharged while the
car was stationary. Furthermore, in his analysis of a large-scale 1996
Canadian study he concluded "all 12 comparisons show females with
airbags at substantially higher risk than those without airbags." It
is clear from Evans' research that the overall effectiveness of airbags in
doing their assigned task is questionable; this makes their potential for
inflicting injuries, including auditory injuries, and death, all the more
- Buckley, G., Setchfield, N., and Frampton, R. (1999). "Two Case
Reports of Possible Noise Trauma After Inflation of Airbags in Low Speed
Car Crashes," Brit. Med. J. 318, 499-500
- Evans, L. (1997). "Offering Motorists the Airbag Option,"
The Washington Times Jun. 8, p. B4
- Garman, J. (1998). "The Auditory Effects of an Airbag Deployment
- An Individual's Experience," J. Acoust. Soc. Am. 104(3), Pt. 2,
- Huelke, D. F., Moore, J. L., Compton, T. W., Rouhana, S. W., and
Kileny, P. R. (1999). "Short Communication: Hearing Loss and Airbag
Deployments," Accident Analysis and Prevention 31(6), 789-792.
- McKinley, R. L. and Nixon, C. W. (1998). "Human Auditory
Response to an Air Bag Inflation Noise: Has It Been 30 Years?," J.
Acoust. Soc. Am. 104(3), Pt. 2, p. 1769.
- Price, G. R. (1997). "Airbags and the Ear - A Story (of)
Unfolding," Spectrum 14(4), p. 1 and 14-15.
- Price, G. R. (1998). "Airbag Noise Hazard: From Theory to
Validation," J. Acoust. Soc. Am. 104(3), Pt. 2, p. 1769.
- Price, G. R. and Kalb, J. T. (1999). "Auditory Hazard from
Airbag Noise Exposure," J. Acoust. Soc. Am 106(5), 2629-2637.
- Saunders, J. E. (1998) "Automobile Airbag Impulse Noise:
Otologic Symptoms in Six Patients," J. Acoust. Soc. Am. 104(3), Pt.
2, p. 1769.
- Yaremchuk, K. (1998). "Otologic Effects of Airbag Deployment,"
J. Acoust. Soc. Am. 104(3) Pt. 2, p. 23.
- Yaremchuk, K. and Dobie, R. A. (1999a). "The Otologic Effects of
Airbag Deployment," J. Occup. Hear. Loss 2(2)(3), 67-73.
- Yaremchuk, K. and Dobie, R. A. (1999b). "The Otologic Effects of
Airbag Deployment," Spectrum Suppl. 1, 16, p.23.