oEPA
United State*
Environmental Protection
Agency
Off ice of
Solid Waste and
Emergency Response
DIRECTIVE NUMBER: 9441.02(85)
TITLE: Exclusion of Sodium Azide in Air Bag Canisters of
Obsolete Automobile Hulks from RCRA Regulations
APPROVAL DATE: i-ie-85
EFFECTIVE DATE: i-ie-85
ORIGINATING OFFICE: office of Solid Waste
S FINAL
D DRAFT
LEVEL OF DRAFT
DA — Signed by AA or OAA
D B — Signed by Office Director
DC — Review & Comment
REFERENCE (other documents):
OSWER OSWER OSWER
VE DIRECTIVE DIRECTIVE Dl
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261 SUBPART A - GENERAL
DOC: 9441.02(85)
Key Words:
Regulations:
Subject:
Addressee:
Originator:
Source Doc:
Date:
Summary:
Exclusion, Commercial Chemical Products
40 CFR 261.33
Exclusion of Sodium Azide in Air Bag Canisters of Obsolete
Automobile Hulks from RCRA Regulations
Hershel Cutler, Executive Director, Institute of Scrap Iron
and Steel, Inc., 1627 K Street, N.W., Washington, D.C. 20006
Jack W. McGraw, Acting Assistant Administrator
#9441.02(85)
1-16-85
Automobile air bags inflate upon ignition when the solid propellant burns
and produces nitrogen gas. The active ingredients in the air bag propellant
cartridges are sodium azide and oxidizers. The gas is generated through the
action of both materials. The sodium azide therefore would not be regulated
under RCRA as a listed hazardous waste because the Agency regulates commercial
chemicals which are pure or technical grade and formulation in which the chemical
is the sole active ingredient. The sodium azide in air bags is not the sole
active ingredient.
The Agency has not established de minimis concentration levels of toxicants
below which wastes listed under §261.33 would no longer be regulated as hazardous
wastes. The Agency grants exemptions on a case-by-case basis in response to
petitions.
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9441.02 (&5)
JIM
Mr. Hershel Cutler
Executive Director
Institute of Scrap Iron and Steel, Inc.
1627 K St., NW
Washington, DC 20006
Dear Mr. Cutler:
. Your letter dated December 10, 1984, was referred to my
office for response. - You expressed concern about the hazards
posed by air bags that contain sodium azide, particularly as it
affects the recovery of ferrous scrap from recycled automobiles.
The Department of Transportation addressed these issues
in a study released July 11, 1984, called Final Regulatory
Impact Analysis, Amendment to FMVSS »20B, Passenger Car Front
Seat Occupant Protection that explored many issues related to
the use of air bags. A NHTSA staff member provided EPA with a
copy of the section that discusses sodium azide. Page 111-20
of that report explains that the gas generants consist mainly
of sodium azide and oxidizers. Page 111-12 explains that upon
ignition, the solid propellant begins to burn, producing
nitrogen gas that inflates the air bag. Based on this
analysis of the mechanics of air bag deployment, the sodium
azide containing initiator would not be regulated as a commercial
chemical product regulated by the hazardous waste regulations
of the Environmental Protection Agency. EPA regulates commercial
chemicals which are pure, or technical grade and formulations
'in which the chemical is the sole, active ingredient. Air baq
propellant cartridges contain, as active ingredients, both
sodium azide and oxidizers. The gas is generated through the
action of both materials. Thus, the Resrource Conservation and
Recovery Act would not define the sodium azide in air bag
canisters of obsolete automobile hulks as a listed hazardous
waste.
The Agency has not established de minimis concentration
levels of toxicants below which wastes listed under 5261.33
would cease to be regulated as hazardous wastes. Rather,
exemptions are granted on a case-by-case basis in response to
petitions. Again, the sodium azide that is in air bags would
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not 09 suoject to RCRA regulation a* a hazardous wasta because
it is not a sole active ingredient.
' EPA in preparing a new regulation that would regulate
certain mixtures of commercial chemical products. Under such
a regulation, it is conceivable that the propellant cartridges
could be classified as a hazardous waste. However, as- wa now
envision such a regulation, auto hulks contaminated with either
sodium azide or the propellent cartridges would not be so
classified. In addition, If the air bags are deployed within
the auto, the sodium aside is destroyed and there would be no
question of even the spent canisters alone being considered
subject to regulation. If the canisters were reclaimed, they
would also not be regulated. The only case which may be regulated
would be canisters which are removed and disposed of, which
appears to be an unlikely scenario at the present time.
The DOT study on sodium azide propellants concluded that
non-deployed inflator modules can be deployed, that an electrical-
deployment system is available now, that technical inspections
for non-deployed modules are available, that a new retrofit
air bag system is easily removed (and should have reasonably
high salvage value), and that about 0.1 pound of sodium azide
per site would be landfilled each working day. This study
used a conservative estimate for the amount of sodium azide
expected in each car, and EPA does not believe this management
of sodium azide' to be a problem at this tHe. Moreover,
EPA understands that auto manufacturers have expressed an
interest in providing incentives for removal and collection of
air bag canisters, which would further reduce the environmental
dispersion of sodium azide.
DOT regulation of deployment of. inflator modules and
reclamation of air baj canisters appears to pose no environmental
concerns that EPA jurisdiction should address at this time.
If you have any further questions, please contact Alan Corson
or Irene Homer of my staff at (202) 382-4770 for assistance.
Sincerely yours,
Jack W. McGraw
Acting Assistant Administrator
bcc: Ruth Bell, OGC
Joyce Dain, TSCA
William Fanj , NHTSA
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