[Federal Register Volume 85, Number 229 (Friday, November 27, 2020)]
[Notices]
[Pages 76159-76174]
[FR Doc No: 2020-26148]

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DEPARTMENT OF TRANSPORTATION

National Highway Traffic Safety Administration

[Docket No. NHTSA-2016-0124; Notice of Agency Decision]

General Motors LLC, Denial of Consolidated Petition for Decision
of Inconsequential Defect

AGENCY: National Highway Traffic Safety Administration (NHTSA),
Department of Transportation.

ACTION: Denial of consolidated petition.

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SUMMARY: TK Holdings Inc. (``Takata'') has filed defect information
reports (DIRs), in which it determined that a defect exists in certain
passenger-side frontal air bag inflators that it manufactured,
including passenger-side inflators that it supplied to General Motors,
LLC (GM) for use in certain GMT900 vehicles. GM petitioned NHTSA for a
decision that, because of differences in inflator design and vehicle
integration, the equipment defect determined to exist by Takata is
inconsequential as it relates to motor vehicle safety in GM's GMT900
vehicles, and that GM should therefore be relieved of its notification
and remedy obligations under the National Traffic and Motor Vehicle
Safety Act of 1966 and its applicable regulations. After reviewing GM's
consolidated petition, supporting materials, and public comments, NHTSA
has concluded that GM has not met its burden of establishing that the
defect is inconsequential to motor vehicle safety, and denies the
petition.

ADDRESSES: For further information on this decision contact Stephen
Hench, Office of Chief Counsel, National Highway Traffic Safety
Administration, 1200 New Jersey Avenue SE, W41-326, Washington, DC
20590 (telephone:<PHONE_NUMBER>).
    For general information regarding NHTSA's investigation into Takata
air bag inflator ruptures and the related recalls: www.nhtsa.gov/takata.

SUPPLEMENTARY INFORMATION:

I. Background

    The Takata air bag inflator recalls (``Takata recalls'') are the
largest and most complex vehicle recalls in U.S. history. These recalls
currently involve 19 vehicle manufacturers and over 60 million Takata
air bag inflators in tens of millions of vehicles in the United States
alone.\1\ The recalls are due to a design defect, whereby the
propellant used in Takata's air bag inflators degrades after long-term
exposure to high humidity and temperature cycling. During air bag
deployment, this propellant degradation can cause the inflator to over-
pressurize, causing sharp metal fragments (like shrapnel) to penetrate
the air bag and enter the vehicle compartment. To date, these rupturing
Takata inflators have resulted in the deaths of 18 people across the
United States \2\ and hundreds of injuries, including lacerations and
other serious consequences to occupants' face, neck, and chest areas.
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    \1\ These numbers include the approximately 5.9 million GMT900
vehicles and associated passenger inflators addressed by this
decision.
    \2\ Globally, including the United States, the deaths of at
least 30 people are attributable to these rupturing Takata
inflators.
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    In May 2015, NHTSA issued, and Takata agreed to, a Consent
Order,\3\ and Takata filed four defect information reports (``DIRs'')
\4\ for inflators installed in vehicles manufactured by twelve \5\
vehicle manufacturers. Recognizing that these unprecedented recalls
would involve many challenges for vehicle manufacturers and consumers,
NHTSA began an administrative proceeding in June 2015 providing public
notice and seeking comment (Docket Number NHTSA-2015-0055) that
culminated in NHTSA's establishment of a

Coordinated Remedy Program (``Coordinated Remedy'') in November
2015.\6\ The Coordinated Remedy prioritizes and phases the various
Takata recalls to not only accelerate the repairs, but also--given the
large number of affected vehicles--to ensure that repair parts are
available to fix the highest-risk vehicles first.\7\
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    \3\ The May 2015 Consent Order is available at: https://www.nhtsa.gov/sites/nhtsa.dot.gov/files/documents/consent-order-takata-05182015_0.pdf.
    \4\ Recall Nos. 15E-040, 15E-041, 15E-042, and 15E-043.
    \5\ The twelve vehicle manufacturers affected by the May 2015
recalls were: BMW of North America, LLC; FCA US, LLC (formerly
Chrysler); Daimler Trucks North America, LLC; Daimler Vans USA, LLC;
Ford Motor Company; General Motors, LLC; American Honda Motor
Company; Mazda North American Operations; Mitsubishi Motors North
America, Inc.; Nissan North America, Inc.; Subaru of America, Inc.;
and Toyota Motor Engineering and Manufacturing.
    \6\ See Notice of Coordinated Remedy Program Proceeding for the
Replacement of Certain Takata Air Bag Inflators, 80 FR 32197 (June
5, 2015).
    The Coordinated Remedy Order, which established the Coordinated
Remedy, is available at: https://www.nhtsa.gov/sites/nhtsa.dot.gov/files/documents/nhtsa-coordinatedremedyorder-takata.pdf. The Third
Amendment to the Coordinated Remedy Order incorporated additional
vehicle manufacturers, that were not affected by the recalls at the
time NHTSA issued the CRO into the Coordinated Remedy, and is
available at: https://www.nhtsa.gov/sites/nhtsa.dot.gov/files/documents/final_public_-_third_amendment_to_the_coordinated_remedy_order_with_annex_a-corrected_12.16.16.pdf. The additional affected vehicle
manufacturers are: Ferrari North America, Inc.; Jaguar Land Rover
North America, LLC; McLaren Automotive, Ltd.; Mercedes-Benz US, LCC;
Tesla Motors, Inc.; Volkswagen Group of America, Inc.; and, per
Memorandum of Understanding dated September 16, 2016, Karma
Automotive on behalf of certain Fisker vehicles.
    \7\ See Coordinated Remedy Order at 15-18, Annex A; Third
Amendment to the Coordinated Remedy Order at 14-17. These documents,
among other documents related to the Takata recalls discussed
herein, are available on NHTSA's website at http://www.nhtsa.gov/takata.
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    Under the Coordinated Remedy, vehicles are prioritized for repair
parts based on various factors relevant to the safety risk--primarily
on vehicle model year (MY), as a proxy for inflator age, and geographic
region. In the early stages of the Takata inflator recalls, affected
vehicles were categorized as belonging to one of two regions: The High
Absolute Humidity (``HAH'') region (largely inclusive of Gulf Coast
states and tropical island states and territories), or the non-HAH
region (inclusive of the remaining states and the District of
Columbia). On May 4, 2016, NHTSA issued, and Takata agreed to, an
amendment to the November 3, 2015 Consent Order (``ACO''), wherein
these geographic regions were refined based on improved understanding
of the risk, and were then categorized as Zones A, B, and C. Zone A
encompasses the higher risk HAH region as well as certain other
states,\8\ Zone B includes states with more moderate climates (i.e.,
lower heat and humidity than Zone A),\9\ and Zone C includes the
cooler-temperature states largely located in the northern part of the
country.\10\
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    \8\ Zone A comprises the following U.S. states and
jurisdictions: Alabama, California, Florida, Georgia, Hawaii,
Louisiana, Mississippi, South Carolina, Texas, Puerto Rico, American
Samoa, Guam, the Northern Mariana Islands (Saipan), and the U.S.
Virgin Islands. Amendment to November 3, 2015 Consent Order at ]
7.a.
    \9\ Zone B comprises the following U.S. states and
jurisdictions: Arizona, Arkansas, Delaware, District of Columbia,
Illinois, Indiana, Kansas, Kentucky, Maryland, Missouri, Nebraska,
Nevada, New Jersey, New Mexico, North Carolina, Ohio, Oklahoma,
Pennsylvania, Tennessee, Virginia, and West Virginia. Amendment to
November 3, 2015 Consent Order at ] 7.b.
    \10\ Zone C comprises the following U.S. states and
jurisdictions: Alaska, Colorado, Connecticut, Idaho, Iowa, Maine,
Massachusetts, Michigan, Minnesota, Montana, New Hampshire, New
York, North Dakota, Oregon, Rhode Island, South Dakota, Utah,
Vermont, Washington, Wisconsin, and Wyoming. Amendment to November
3, 2015 Consent Order at ] 7.c.
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    The ACO also required Takata to declare on a rolling basis a defect
in all frontal driver and passenger-side air bag inflators that contain
a phase-stabilized ammonium nitrate (``PSAN'')-based propellant without
a moisture-absorbing desiccant. The first DIR was due on May 16, 2016;
the second on December 31, 2016; the third on December 31, 2017; the
fourth on December 31, 2018; and the fifth on December 31, 2019.\11\
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    \11\ NHTSA has permitted Takata to file within a few days of
these deadlines to account for weekends and holidays.
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GM's May 27, 2016 DIRs and First Petition

    Takata timely submitted the first scheduled equipment DIRs on May
16, 2016.\12\ Those DIRs included non-desiccated passenger inflators,
designated as SPI YP (``YP'') and PSPI-L YD (``YD'') variants, that
were installed as original equipment on certain GMT900 motor vehicles
manufactured by GM, as well as other non-desiccated passenger inflators
installed as original equipment on motor vehicles manufactured by GM
that are not at issue here. The Takata filing triggered GM's obligation
to file a DIR for the affected GM vehicles.\13\ GM submitted two DIRs
on May 27, 2016. On November 15, 2016, GM submitted a Petition for
Inconsequentiality and Request for Deferral of Determination Regarding
Certain GMT900 Vehicles Equipped with Takata ``SPI YP'' and ``PSPI-L
YD'' Passenger Inflators (the ``First Petition for Inconsequentiality''
or ``First Petition''), pursuant to 49 U.S.C. 30118(d), 30120(h) and 49
CFR part 556. In the First Petition, GM requested that NHTSA defer its
decision on inconsequentiality until GM was able to complete its
testing and engineering analysis in August 2017.\14\
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    \12\ See Recall Nos. 16E-042, 16E-043, and 16E-044.
    \13\ See 49 CFR part 573; ACO at ] 16; Third Amendment to
Coordinated Remedy Order at ] 32.
    \14\ First Petition at 18.
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    On November 28, 2016, the Agency published a notice of receipt of
the First Petition in the Federal Register and granted two
administrative requests.\15\ First, as a matter of its enforcement
discretion, NHTSA accepted the First Petition even though it was filed
outside the regulatory thirty-day filing deadline.\16\ Second, based on
unique facts and circumstances, NHTSA granted GM's request for
additional time to conduct research and submit information to the
Agency, and allowed GM until August 31, 2017 to develop and present
further evidence, data, and information before issuing a decision on
the First Petition. NHTSA opened public docket no. NHTSA-2016-0124 as a
repository for the Petition and supporting materials, and to receive
public comments until September 14, 2017.
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    \15\ 81 FR 85681 (Nov. 28, 2016).
    \16\ 49 CFR 556.4(c).
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    NHTSA further required that GM submit monthly testing updates. GM
submitted such updates for December 2016 and January through July 2017,
and a comprehensive submission in August 2017 that included testing,
statistical analysis, and other information. GM also presented
technical briefings to NHTSA on August 16, 2017 and August 23, 2017. On
September 15, 2017, NHTSA sent follow-up questions to GM seeking
clarification of information GM had provided, and GM submitted
responses on September 29, 2017 (``GM's September 2017 Response''). GM
continued providing additional updates to NHTSA at meetings on February
12, April 9, and June 8, 2018. NHTSA sent GM additional follow-up
questions to the June 8 meeting on July 10, 2018, and GM submitted
responses to those questions on July 20, 2018 (``GM's July 2018
Response'').
    GM submitted voluminous materials to the Agency over the course of
about two years, including materials from Orbital-ATK (``OATK'') \17\
and Cornerstone Research (``Cornerstone'').\18\ To apprise the public
of this information--which the Agency was considering in rendering the
instant decision--the Agency regularly posted GM's materials on public
docket no. NHTSA-2016-0124.\19\ The Agency

further offered the opportunity for public comment, and comments were
both received and considered.
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    \17\ OATK was subsequently purchased by Northrop Grumman. For
simplicity and continuity across NHTSA's documents regarding the
Takata inflator recalls and Coordinated Remedy, NHTSA will continue
to refer to the company as OATK.
    \18\ GM also retained Professor Arnold Barnett, the George
Eastman Professor of Management Science and Professor of Statistics
at the Massachusetts Institute of Technology, who worked with
Cornerstone Research, to provide GM's statistical assessment.
    \19\ Docket no. NHTSA-2016-0124 can be accessed at https://www.regulations.gov/docket?D=NHTSA-2016-0124. Note that limited
materials, including materials subject to requests for confidential
treatment, are included in the docket via incorporation by memo.
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GM's January 10, 2017 DIRs and Second Petition

    On January 3, 2017, Takata timely submitted the second scheduled
equipment DIRs.\20\ The Takata filing triggered GM's obligation to file
a DIR for the affected GM vehicles,\21\ and GM submitted DIRs on
January 10, 2017 recalling additional GMT900 vehicles as well as other
vehicles containing non-desiccated PSAN inflators supplied to GM that
are not at issue here. GM notified NHTSA of its intention to file a
petition for an exemption from its recall notification and remedy
obligations as to the GMT900 vehicles only, and submitted a Petition
for Inconsequentiality and Request for Deferral of Determination
Regarding Certain GMT900 Vehicles Equipped with Takata ``SPI YP'' and
``PSPI-L YD'' Passenger Inflators Subject to January 2017 Takata
Equipment DIR Filings (the ``Second Petition for Inconsequentiality''
or ``Second Petition''). On September 11, 2017, the Agency published a
notice of receipt of the Second Petition and consolidated the First
Petition with the Second Petition in Docket No. NHTSA-2016-0124.\22\
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    \20\ See Recall Nos. 17E-001, 17E-002, and 17E-003.
    \21\ See 49 CFR part 573; ACO at ] 16; Third Amendment to
Coordinated Remedy Order at ] 32.
    \22\ 82 FR 42718 (Sept. 11, 2017). GM also filed a Supplemental
Brief in Support of Petitions for Inconsequentiality Regarding
Certain GMT900 Vehicles following submission of the Second Petition,
which is also available in the public docket.
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GM's January 9, 2018 DIRs and Third Petition

    Takata timely submitted the third scheduled equipment DIRs on
January 2, 2018.\23\ The Takata filing triggered GM's obligation to
file a DIR for the affected GM vehicles,\24\ and GM submitted DIRs on
January 9, 2018 recalling additional GMT900 vehicles as well as other
vehicles containing non-desiccated PSAN inflators supplied to GM not at
issue here. GM notified NHTSA of its intention to file a petition for
an exemption from its recall notification and remedy obligations as to
the GMT900 vehicles only, and submitted a Petition for
Inconsequentiality Regarding Certain GMT900 Vehicles Equipped with
Takata ``SPI YP'' and ``PSPI-L YD'' Passenger Inflators Subject to
January 2018 Takata Equipment DIR Filings (the ``Third Petition for
Inconsequentiality'' or ``Third Petition''). On April 9, 2018, the
Agency published a notice of receipt of the Third Petition and
consolidated the Third Petition with the previously consolidated First
and Second Petitions.\25\ NHTSA also reopened the public docket to take
additional comment on GM's Petition and supporting materials. The
closing date for the re-opened comment period was May 9, 2018.
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    \23\ See Recall Nos. 18E-001, 18E-002, and 18E-003.
    \24\ See 49 CFR part 573; ACO at ] 16; Third Amendment to
Coordinated Remedy Order at ] 32.
    \25\ 83 FR 15233 (Apr. 9, 2018).
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GM's January 9, 2019 DIRs and Fourth Petition

    Takata timely submitted the fourth scheduled equipment DIRs on
January 2, 2019.\26\ The Takata filing triggered GM's obligation to
file a DIR for the affected GM vehicles,\27\ and GM submitted DIRs on
January 9, 2019 recalling additional GMT900 vehicles as well as other
vehicles containing non-desiccated PSAN inflators supplied to GM that
are not at issue here. GM notified NHTSA of its intention to file a
petition for an exemption from its recall notification and remedy
obligations as to the GMT900 vehicles only, and submitted a Petition
for Inconsequentiality Regarding Certain GMT900 Vehicles Equipped with
Takata ``SPI YP'' and ``PSPI-L YD'' Passenger Inflators Subject to
January 2019 Takata Equipment DIR Filings (the ``Fourth Petition for
Inconsequentiality'' or ``Fourth Petition''). On June 18, 2019, the
Agency published notice of the Fourth Petition and consolidated it with
the previously consolidated Petitions (collectively referred to as
``the Petition'' or ``GM's Petition'').\28\ NHTSA also reopened the
public docket to take additional comment on GM's Petition and
supporting materials. The closing date for the re-opened comment period
was July 18, 2019.
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    \26\ Recall Nos. 19E-001, 19E-002, and 19E-003.
    \27\ See 49 CFR part 573; ACO at ] 16; Third Amendment to
Coordinated Remedy Order at ] 32.
    \28\ 83 FR 15233 (June 18, 2019).
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Public Comments on GM's Petition

    NHTSA opened public docket number NHTSA-2016-0124 to provide the
public an opportunity to review the data and information GM submitted
in support of the Petition. NHTSA has taken into consideration all
comments posted to the docket as of November 19, 2020.
    As of that date, 302 comments have been posted to the docket. No
comments were filed in support of granting the Petition, and few
address technical aspects of GM's Petition or data. Many comments
referred either to concerns with selling unrepaired vehicles, or to the
economic hardship or disadvantage experienced as a result of diminished
resale or trade-in value for vehicles with unrepaired inflators. Many
commenters also expressed general concern about the air bags in their
GMT900 vehicles. Since NHTSA concludes here that GM's Petition should
be denied, those comments are not discussed here.

II. Motor Vehicles Involved

    GM's Petition involves certain ``GMT900'' vehicles that contain
``SPI YP'' and ``PSPI-L YD'' inflator variants. GMT900 is a GM-specific
vehicle platform that forms the structural foundation for a variety of
GM light- and heavy-duty pickup trucks and sport utility vehicles,
including: Chevrolet Silverado 1500, GMC Sierra 1500, Chevrolet
Silverado 2500/3500, GMC Sierra 2500/3500, Chevrolet Tahoe, Chevrolet
Suburban, Chevrolet Avalanche, GMC Yukon, GMC Yukon XL, Cadillac
Escalade, Cadillac Escalade ESV, and Cadillac Escalade EXT. The
Petition involves approximately 5.9 million MY 2007-2014 GMT900
vehicles in Zones A, B, and C.\29\
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    \29\ Fourth Petition at 2. Based on information provided to
NHTSA by GM, the precise number of vehicles under petition is
5,888,421.
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III. Summary of GM's Petition and Supporting Information

    GM has petitioned the Agency for a decision that the Takata PSAN
defect in the GMT900 vehicles is inconsequential as it relates to motor
vehicle safety, and that GM should therefore be relieved of its
notification and remedy obligations. GM asserts two primary arguments
for why the defect should be deemed inconsequential in GMT900 vehicles.
First, GM asserts that there are multiple ``unique'' design differences
in the YD and YP variant inflators used in GMT900 vehicles that result
in a reduced risk of rupture. Second, GM argues that the physical
environment in GMT900 vehicles ``better protects the front-passenger
inflator from the extreme temperature cycling that can cause inflator
rupture.'' \30\ GM's primary arguments and supporting information are
summarized below.
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    \30\ See id. at 11-12.
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A. Unique Inflator Design Differences and Vehicle Features

    GM claims that the YD and YP variant inflators in GMT900 vehicles
are not used by any other vehicle manufacturers and that these inflator
variants have a

number of unique design features that result in a reduced risk of
inflator rupture.\31\ GM contends that these unique design features are
``crucially'' important factors that required Takata to ``heavily
modify the characteristics'' of their inflators in order to meet GM's
standards.\32\ As noted in GM's petitions and information presented to
NHTSA, these alleged design differences include the following:
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    \31\ See id. at 12; Second Petition at 11-12; Third Petition at
5-8; Fourth Petition at 5-7.
    \32\ Fourth Petition at 6; see Third Petition at 6. GM's Third
Petition asserts that strict adherence to the United States Council
for Automotive Research (``USCAR'') air bag performance standards
``resulted in [GM] inflators with increased inflator-structural
integrity, better ballistic performance, and greater resistance to
moisture.'' Third Petition at 6. NHTSA notes that USCAR standards
are utilized across the industry and adherence to those standards is
not particular to the GMT900 inflators at issue.
     In all events, for the reasons discussed here, GM has failed to
meet its burden to show that the defect at issue here is
inconsequential to motor vehicle safety.
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    Thinner Propellant Wafers. GM claims that the thinner (8mm)
propellant wafers used in the GMT900 inflators have more predictable
ballistic properties than thicker (11mm) wafers used in many other
Takata PSAN inflator variants, which ``create less excess surface area
as they degrade.'' \33\ As a result, GM contends that the thinner
propellant wafers used in the GMT900 vehicles age more slowly and burn
more efficiently than thicker propellant wafers, resulting in a reduced
risk of inflator rupture.\34\
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    \33\ Fourth Petition at 6-7; see Third Petition at 6.
    \34\ See Third Petition at 6; Fourth Petition at 6-7.
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    Larger Vent Area. GM claims that a greater vent-area-to-propellant-
mass ratio provides for more efficient burning and deployment of the
GMT900 inflators, resulting in a reduced risk of inflator rupture.\35\
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    \35\ See Fourth Petition at 7.
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    Steel Endcap. GM claims that the steel endcap used on the GMT900
inflators creates an improved hermetic seal compared to the aluminum
endcaps used on other Takata PSAN inflators, and therefore better
protects the propellant from moisture.\36\ GM also claims that the use
of steel endcaps improves the inflators' ``resistance to high-internal
pressures.'' \37\
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    \36\ See id.
    \37\ Id.
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    Other Design Differences. GM observed several other design
differences in its presentations to NHTSA, including tablets in a cup
(for YP variants), the incorporation of a ceramic cushion (also for YP
variants), and the incorporation of a bulkhead disk with an anvil (for
YD variants).\38\ While noted and discussed during presentations, these
design differences were not explicitly referenced or otherwise
significantly expounded upon in GM's Petition documents.
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    \38\ See GM's June 8, 2018 Presentation at 126; GM's August 23,
2017 Presentation at 111, 113; GM's April 5, 2017 Presentation at
84.
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    GM also asserts that the physical environment in GMT900 vehicles
better protects the front-passenger inflators from extreme temperature
cycling that can cause inflator rupture. GM claims that the GMT900
vehicles have larger cabin volumes than other vehicles equipped with
Takata PSAN inflators, and are all equipped with solar-absorbing glass
windshields and side glass, which results in lower internal vehicle
temperatures and thus a reduced risk of inflator rupture.\39\
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    \39\ Fourth Petition at 7; Second Petition at 11-12; First
Petition at 12; Third Petition at 7.
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B. Additional Supporting Data and Information

    GM contends that the passenger inflators at issue are currently
performing as designed, and will continue to function properly without
risk of rupture for at least 30 to 35 years of service in the
field.\40\ In support of this argument, GM cites ballistic testing,
aging studies, predictive modeling, and other analyses that it has
conducted over the last several years.
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    \40\ See GM's June 8, 2018 Presentation at 4, 32. This
contention is based on 35 years of artificial aging (worst-case
field exposure in Miami, Florida) of newly manufactured inflators,
described infra. Id.
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1. Testing & Field Data Analyses
    Testing by Takata. GM retrieved inflators from the field by
removing parts from vehicles (a ``field return'' part or inflator) and
sent them to Takata for ballistic testing and analysis. In total,
Takata conducted ballistic tests of more than 4,200 field return
inflators, with the majority (1,620 YD and 2,235 YP inflators) coming
from Zone A.\41\ GM states that none of the tested GMT900 inflators
have ruptured.\42\ Takata's testing further included CT scans of
inflators to measure average and maximum wafer diameters of more than
5,000 YD and YP variant inflators, and GM also pointed to micro-CT and
high-speed x-ray cinematography, which enabled researchers to view
pores and fissures caused by PSAN propellant degradation.\43\
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    \41\ Fourth Petition at 12-13; Third Petition at 13. GM's Third
Petition cites 1,620 YD and 2,235 YP inflators and a ``vast
majority'' coming from Zone A GMT900 vehicles, while GM's Fourth
Petition cites 1,197 YD and 2,249 YP inflators and a ``majority''
coming from Zone A GMT900 vehicles.
    \42\ Fourth Petition at 12; Third Petition at 13.
    \43\ GM's June 8, 2018 Presentation at 37; GM's April 5, 2017
Presentation at 60-64, 70; see Exhibit A, Report of Dr. Harold
Blomquist (``2020 Blomquist Report'') at paras. 88, 221 & n.120.
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    Stress-Strength Interference Analysis. GM conducted a stress-
strength interference analysis of the GMT900 vehicle inflators based on
CT scans of 1,578 YD and YP inflators.\44\ GM explains stress-strength
interference analysis as the plotting of curves on a graph related to
the diameter of field-returned YP and YD inflators and the diameter of
non-GM inflators that have ruptured during ballistic testing; the
amount of overlap between the two curves ``represents the probability
of rupture in a particular group of inflators.'' \45\ GM provides plots
of curves with no discernable overlap,\46\ and concludes that ``even
the oldest (MY 2007) Zone A Takata GMT 900 inflators are not at risk of
rupture.'' \47\
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    \44\ Second Petition at 15-16; see also First Petition at 15-16.
    \45\ Second Petition at 16; First Petition at 16.
    \46\ See Second Petition, Exs. B & C; First Petition, Exs. B &C.
    \47\ First Petition at 3; see Second Petition at 15-17.
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    Crash Deployment Estimates. GM estimates that its GMT900 vehicles
equipped with YD and YP inflators have been involved in approximately
66,894 crashes where the passenger air bag has deployed, all allegedly
without a field rupture.\48\ GM asserts that this data demonstrates
that the GMT900 inflators are ``currently performing as designed.''
\49\
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    \48\ Fourth Petition at 12; see GM's June 8, 2018 Presentation
at 36. The 66,894 figure is referenced in GM's Fourth Petition,
while GM's June 8, 2018 Presentation references 68,206 deployments.
    \49\ Fourth Petition at 12.
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2. Aging Studies
    GM conducted a preliminary Aging Study (``GM Aging Study''), and
later engaged a third party, OATK, to conduct a larger ``long-term''
Aging Study (``OATK Aging Study'') to simulate the propellant
degradation process that occurs in Takata PSAN inflators.\50\ It is the
Agency's understanding that both studies were informed by vehicle
temperature studies conducted by GM (the ``GM Temperature Study'') and
Atlas Material Testing Solutions (the ``Atlas Cabin Temperature
Study'').\51\ For the GM Temperature Study, GM studied the Pontiac Vibe
and two GMT900 vehicle models (Silverado and Suburban).\52\ The Atlas
Cabin

Temperature Study studied the Pontiac Vibe and 11 non-GM vehicles.\53\
GM asserts these studies demonstrate that GMT900 vehicles normally
achieve a relatively low peak vehicle temperature (below 60[deg]C, or
what GM refers to as the ``T1'' temperature range).\54\ GM utilized
these temperature studies in its aging studies as described below.
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    \50\ See First Petition at 3, 14-15; Fourth Petition at 13-16;
GM's August 23, 2017 Presentation at 94-97; GM's April 5, 2017
Presentation at 80-82.
    \51\ See GM's June 8, 2018 Presentation at 11, 14.
    \52\ See GM's August 23, 2017 Presentation at 171.
    \53\ See id.
    \54\ See GM's June 8, 2018 Presentation at 11, 14.
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    GM Aging Study. GM conducted a preliminary aging study of a small
number of inflators, including field-return parts (both YP and YD
variant inflators) to demonstrate the short-term safety of its
inflators while the Petition was pending.\55\ GM artificially aged the
inflators by imposing four-hour cycles of temperature and humidity
cycling per day for fifty-eight days, in closed-test laboratory
chambers.\56\ Though none of the inflators ruptured or demonstrated
elevated pressure, all showed signs of wafer diameter growth.\57\
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    \55\ See First Petition at 3, 14-15; GM's August 23, 2017
presentation at 94-97; GM's April 5, 2017 Presentation to NHTSA at
80-82.
    \56\ First Petition at 14-15.
    \57\ Id.; see GM's August 23, 2017 Presentation at 94-97.
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    OATK Aging Study. GM retained OATK to conduct a long-term aging
study to evaluate the future performance of GMT900 inflators through
simulated laboratory aging.\58\ Takata specially constructed YD, YP,
and FD variant inflators for use in the OATK Aging Study.\59\ The
primary chambers in the inflators were loaded with three different
levels of moisture: (1) No moisture added; (2) ``internal moisture
approximately equal to 90th percentile moisture levels in Zone A''; and
(3) ``moisture levels approximately two-times higher than the highest
level ever measured in a GMT900 Inflator recovered from Zone A.'' \60\
The OATK Aging Study employed four-hour temperature cycles; by June
2018, OATK had conducted 1,960 cycles of testing, which GM asserts
simulated 35 years of field aging.\61\ According to GM, ``all of the
GMT900 Inflators in the study safely deployed without any ruptures,''
leading GM to the conclusion that the YP and YD inflators are safer and
more resistant to rupture than other Takata PSAN inflators.\62\ GM
asserts that the study demonstrates the GMT900 inflators ``will
continue to operate safely for decades, even in the highest temperature
and humidity regions.'' \63\
---------------------------------------------------------------------------

    \58\ Fourth Petition at 7-8; Third Petition at 8 & Ex.C.
    \59\ Fourth Petition at 8; Third Petition at 9 & Ex.C.
    \60\ Fourth Petition at 8; Third Petition at 9.
    \61\ See GM's August 23, 2017 Presentation at 12, 15; GM's June
8, 2018 Presentation at 4, 81; Fourth Petition at 13; Second
Petition at 32-33 (Ex.D).
    \62\ Fourth Petition at 3; Third Petition at 3, 11.
    \63\ Id. at 3; see Fourth Petition at 3-4.
---------------------------------------------------------------------------

3. Predictive Modeling
    In 2018, GM presented results of a parametric mathematical model
created by OATK (the ``OATK Model'' or ``the Model'') that was designed
to predict the service-life expectancy of GMT900 inflators.\64\ It is
the Agency's understanding that this Model was informed by the GM
Temperature Study and the Atlas Cabin Temperature Study, as well as the
GM Aging Study and the OATK Aging Study.\65\ The Model runs a Monte
Carlo simulation 32,000 times simulating air bag deployments. Each
trial combines variations of several different inputs, including usage
profile (meaning how the vehicle is driven, where it is parked, how
often and high the air conditioning is run, and any other factors that
affect the moisture and temperature environment of the inflator),\66\
peak vehicle temperature, the environmental conditions of the city in
which the inflator resides, and the age of the inflator.\67\ The final
output of the Model is the ``probability of ED'' for a deployed
inflator with these inputs, i.e., the probability that an inflator will
rupture under various circumstances.\68\ From these Model-predicted
outputs, GM concludes that the GMT900 inflators ``will not reach a
threshold risk level within 30 years of worst case environmental field
exposure in Miami [Florida].'' \69\
---------------------------------------------------------------------------

    \64\ Fourth Petition at 16.
    \65\ See GM's June 8, 2018 Presentation at 11, 14, 48.
    \66\ 2020 Blomquist Report at para. 189.
    \67\ See GM's June 8, 2018 Presentation at 6-14.
    \68\ Id. at 10, 145.
    \69\ Fourth Petition at 4; GM's June 8, 2018 Presentation at 4,
8 (defining threshold risk level as 1% chance of failure upon
initiation in the 1% vehicle (most severe exposure)).
---------------------------------------------------------------------------

4. Risk Assessments
    GM also presented statistical risk assessments from third parties
Cornerstone and Professor Arnold Barnett, and OATK, which attempted to
quantify the future risk of rupture for the GMT900 inflator
variants.\70\ These risk assessments were based upon data and inputs
from the OATK Model, the OATK Aging Study, Takata's Master Engineering
Analysis File (``MEAF'') file,\71\ and GM's crash-data estimates.\72\
Cornerstone concluded that the rupture risk for GMT900 inflators is
``significantly lower'' than that for ``typical `benchmark' Takata
inflators in other vehicles,'' and that the OATK model ``offers strong
evidence that a GMT900's absolute risk'' of a rupture ``is extremely
small.'' \73\
---------------------------------------------------------------------------

    \70\ June 8, 2018 Presentation at 4; see Fourth Petition at 14.
These assessments were presented at briefings to the Agency in
August 2017, February 2018, and June 2018. Cornerstone attended all
three briefings, while Professor Barnett only attended the August
2017 and June 2018 meetings.
    \71\ For several years, Takata has inspected, tested, and
analyzed inflators returned from the field. The compiled and
summarized test results for more than 387,000 inflator tests or
inspections (as of July 3, 2018), including GMT900 inflators, are
contained in the Takata MEAF. Takata's MEAF file was available to
the Agency in making its determination, and it is from this file
that some of the information considered by the Agency was derived,
and discussed herein.
    \72\ See GM's June 8, 2018 Presentation at 17.
    \73\ Id. at 18.
---------------------------------------------------------------------------

    GM presented several assessments regarding the per-deployment risk,
or the probability that a specific air bag will rupture in a given
deployment.\74\ Based upon the outputs of the OATK Model, GM predicts
the following probabilities of future inflator rupture for inflators
aged 30 years under the Model:\75\
---------------------------------------------------------------------------

    \74\ See, e.g., GM's July 20, 2018 Response, Ex.C. GM sometimes
refers to this as the ``POF'' (probability of failure),
``probability of ED'' (probability of energetic deployment), or ``IR
risk'' (inflator rupture risk).
    GM also asserted that the probability of rupture in a given
deployment is ``zero'' for the YD and YP inflators in the ``long-
term,'' but did not provide supporting information. See GM's
September 29, 2017 Response at 2. GM referred the Agency to GM's
Supplemental Brief, but NHTSA found no information that supported
this assertion, and therefore it is not addressed in NHTSA's
analysis.
    \75\ GM provided hundreds of per-deployment risk estimates based
on various combinations of inputs. See GM's July 2018 Response,
Ex.C. The estimates in this table reflect estimates for inflators
exposed to the most extreme conditions for which GM/OATK calculated
risk.

----------------------------------------------------------------------------------------------------------------
             Vehicle temperature band                             YD                             YP
----------------------------------------------------------------------------------------------------------------
For vehicles with cabin temperature less than       0% (i.e., no risk of rupture)  0% (i.e., no risk of
 60[deg]C (referred to by GM as ``T1'').                                            rupture).
For vehicles with a cabin temperature between 60    0.87% (i.e., 1 rupture per     12% (i.e.,1 rupture per 8
 and 65[deg]C (referred to by GM as ``T2'').         115 deployments).              deployments).
For vehicles with a cabin temperature above         66% (i.e., 2 ruptures per 3    99% (i.e., 99 ruptures per
 65[deg]C (referred to by GM as ``T3'').             deployments).                  100 deployments).
----------------------------------------------------------------------------------------------------------------

    GM asserts that all GMT900 vehicles fall within the lowest ``T1''
vehicle temperature range and therefore have a zero percent risk of
rupture through age 30.\76\ For vehicles that fall within the higher
``T2'' and ``T3'' vehicle temperature ranges, GM provided an estimate
for the number of years until the inflator will have a 1-in-100 chance
of rupturing if deployed: for the YD inflator, between 17.6 and 30-plus
years; for the YP inflator, between 14.6 and 30-plus years.\77\ GM
further provided a lifetime risk estimate--namely, the probability that
an individual inflator will experience at least one rupture over its
lifetime when a person is seated in the front passenger seat, of not
more than 1 in 50 million for the YD inflator variant, and not more
than 1 in 3.4 million for the YP inflator variant.\78\
---------------------------------------------------------------------------

    \76\ See GM's June 8, 2018 Presentation at 14; see also GM's
July 20, 2018 Response, Ex.C.
    \77\ See GM's July 20, 2018 Response, Ex. C.
    \78\ GM's June 8, 2018 Presentation at 26.
---------------------------------------------------------------------------

    GM also provided ``comparative risk'' assessments for the GMT900
inflators.\79\ GM contends that the comparator FD inflators--used in
the Pontiac Vibe and other vehicles--were ``ideal'' because (1) they
are from the same inflator family as the GMT900 light-duty inflator
with certain design and construction similarities, but ``lack the
critical design elements that, in GM's view, distinguish the GMT900
inflators from other Takata non-desiccated PSAN inflators and make the
GMT900 Inflators resistant to the risk of energetic deployment,'' and
(2) the FD inflators ``have consistently experienced ruptures during
ballistic testing'' and have also experienced field ruptures.'' \80\
Based upon the assertion that there have been no GMT900 ruptures in the
OATK Aging Study, field returned samples (based upon MEAF data), or in
the field, GM concludes that if the GMT900 inflators posed the same
risk as other inflators, the probability of observing zero ruptures for
GMT900 inflators given the sample size and when compared to other
inflators is as follows: \81\
---------------------------------------------------------------------------

    \79\ Id. at 21-23, 39; GM's July 20, 2018 Response at 16.
    \80\ Third Petition at 10.
    \81\ GM's June 8, 2018 Presentation at 21-22; see GM's July 20,
2018 Response at 16. GM provided estimates for crash deployments
that have occurred in GMT900 vehicles, and based its risk analyses
on the assumption that there were no ruptures in those crash
deployments. See infra.

----------------------------------------------------------------------------------------------------------------
           When compared to               YD & YP  (pooled)                YD                       YP
----------------------------------------------------------------------------------------------------------------
FD inflators, when each variant is     1 in 499 billion.......  1 in 767,815...........  1 in 649,530.
 artificially aged (OATK Aging Study).
Other inflators (excluding the         1 in 1.5 million.......  1 in 1,551.............  1 in 347.
 Vibe),\82\ when weighted according
 to certain conditions (Field Return,
 MEAF data).
Other 8- to 12-year old inflators in   1 in 10 \22\...........  1 in 41 trillion.......  1 in 174,267.
 Zone A (excluding the Vibe) \83\
 (Field Data Applying Crash
 Deployment Estimates).
----------------------------------------------------------------------------------------------------------------

5. Dealer Replacements as Risk Creation
---------------------------------------------------------------------------

    \82\ More specifically, 8-12-year-old SPI and PSPI-L inflators
from non-GM vehicles (excluding the Vibe). GM's June 8, 2018
Presentation at 39.
    \83\ More specifically, 8-12-year-old SPI and PSPI-L inflators
from non-GM vehicles (excluding the Vibe) in Alabama, Georgia,
Hawaii, Louisiana, Mississippi, South Carolina, and Texas. Id. at
39, 46.
---------------------------------------------------------------------------

    Finally, GM contends that because the GMT900 inflators are ``not at
risk of rupture,'' dealers conducting repairs for the inflators under
petition could ``unnecessarily expose'' occupants ``to the risk of an
improper repair'' \84\ by ``disrupting critical, sensitive, fully
operational safety systems in millions of customer vehicles.'' \85\
---------------------------------------------------------------------------

    \84\ Fourth Petition at 16.
    \85\ Third Petition at 17; see also Fourth Petition at 16; GM's
June 8, 2018 Presentation at 5. Based on information provided to
NHTSA by GM, the total number of vehicles under petition is
5,888,421.
---------------------------------------------------------------------------

IV. NHTSA's Analysis

A. Background

    The National Traffic and Motor Vehicle Safety Act (the ``Safety
Act''), 49 U.S.C. Chapter 301, defines ``motor vehicle safety'' as
``the performance of a motor vehicle or motor vehicle equipment in a
way that protects the public against unreasonable risk of accidents
occurring because of the design, construction, or performance of a
motor vehicle, and against unreasonable risk of death or injury in an
accident, and includes nonoperational safety of a motor vehicle.'' \86\
Under the Safety Act, a manufacturer must notify NHTSA when it ``learns
the vehicle or equipment contains a defect and decides in good faith
that the defect is related to motor vehicle safety,'' or ``decides in
good faith that the vehicle or equipment does not comply with an
applicable motor vehicle safety standard.'' \87\ The act of filing a
notification with NHTSA is the first step in a manufacturer's statutory
recall obligations of notification and remedy.\88\ However, Congress
has recognized that, under some limited circumstances, a manufacturer
may petition NHTSA for an exemption from the requirements to notify
owners, purchasers, and dealers and to remedy the vehicles or equipment
on the basis that the defect or noncompliance is inconsequential to
motor vehicle safety.\89\
---------------------------------------------------------------------------

    \86\ 49 U.S.C. 30102(a)(9).
    \87\ Id. 30118(c)(1). ``[A] defect in original equipment, or
noncompliance of original equipment with a motor vehicle safety
standard prescribed under this chapter, is deemed to be a defect or
noncompliance of the motor vehicle in or on which the equipment was
installed at the time of delivery to the first purchaser.'' 49
U.S.C. 30102(b)(1)(F).
    \88\ Id. 30118-20.
    \89\ Id. 30118(d), 30120(h); 49 CFR part 556.
---------------------------------------------------------------------------

    ``Inconsequential'' is not defined either in the statute or in
NHTSA's regulations, and so must be interpreted based on its
``ordinary, contemporary, common meaning.'' \90\ The inconsequentiality
provision was added to the statute in 1974, and there is no indication
that the plain meaning of the term has changed since 1961--meaning
definitions used today are substantially the same as those used in
1974.\91\ The Cambridge Dictionary defines ``inconsequential'' to mean
``not important'' or ``able to be ignored.'' \92\ Other dictionaries
similarly define the term as ``lacking importance'' \93\ and
``unimportant.'' \94\
---------------------------------------------------------------------------

    \90\ See, e.g., Food Mktg. Institute v. Argus Leader Media, 139
S. Ct. 2356, 2363 (2019) (quoting Perrin v. United States, 444 U.S.
37, 42 (1979)).
    \91\ See Pub. L. 93-492, Title I, Sec.  102(a), 88 Stat. 1475
(Oct. 27, 1974); Webster's Third New Int'l Dictionary (principal
copyright 1961) (defining ``inconsequential'' as ``inconsequent;'
defining ``inconsequent'' as ``of no consequence,'' ``lacking worth,
significance, or importance'').
    The House Conference Report indicates that the Department of
Transportation planned to define ``inconsequentiality'' through a
regulation; however, it did not do so. See H.R. Rep. 93-1191, 1974
U.S.C.C.A.N. 6046, 6066 (July 11, 1974). Instead, NHTSA issued a
procedural regulation governing the filing and disposition of
petitions for inconsequentiality, but which did not address the
meaning of the term ``inconsequential.'' 42 FR 7145 (Feb. 7, 1977).
The procedural regulation, 49 CFR part 556, has remained largely
unchanged since that time, and the changes that have been made have
no effect on the meaning of inconsequentiality.
    \92\ https://dictionary.cambridge.org/us/dictionary/english/inconsequential.
    \93\ https://ahdictionary.com/word/search.html?q=inconsequential.
    \94\ https://www.merriam-webster.com/dictionary/inconsequential.

---------------------------------------------------------------------------

    The statutory context is also relevant to the meaning of
``inconsequential.'' \95\ The full text of the inconsequentiality
provision is:
---------------------------------------------------------------------------

    \95\ See, e.g., Taniguchi v. Kan Pac. Saipan, Ltd., 566 U.S.
560, 569-72 (2012) (considering ordinary and technical meanings, as
well as statutory context, in determining meaning of a
``interpreter'' under 28 U.S.C. 1920(6)).

    On application of a manufacturer, the Secretary shall exempt the
manufacturer from this section if the Secretary decides a defect or
noncompliance is inconsequential to motor vehicle safety. The
Secretary may take action under this subsection only after notice in
the Federal Register and an opportunity for any interested person to
present information, views, and arguments.\96\
---------------------------------------------------------------------------

    \96\ 49 U.S.C. 30118(d), 30120(h).

    As described above, the statute defines ``motor vehicle safety'' to
mean ``the performance of a motor vehicle or motor vehicle equipment in
a way that protects the public against unreasonable risk of accidents .
. . and against unreasonable risk of death or injury in an accident . .
. .'' \97\ This is also consistent with the overall statutory purpose:
``to reduce traffic accidents and deaths and injuries resulting from
traffic accidents.'' \98\
---------------------------------------------------------------------------

    \97\ Id. 30102(a)(9) (emphasis added).
    \98\ Id. 30101.
---------------------------------------------------------------------------

    The statute explicitly allows a manufacturer to seek an exemption
from carrying out a recall on the basis that either a defect or a
noncompliance is inconsequential to motor vehicle safety.\99\ However,
in practice, substantially all inconsequentiality petitions have
related to noncompliances, and it has been extremely rare for a
manufacturer to seek an exemption in the case of a defect. This is
because a manufacturer does not have a statutory obligation to conduct
a recall for a defect unless and until it ``learns the vehicle or
equipment contains a defect and decides in good faith that the defect
is related to motor vehicle safety,'' or NHTSA orders a recall by
making a ``final decision that a motor vehicle or replacement equipment
contains a defect related to motor vehicle safety.'' \100\ Until that
threshold determination has been made by either the manufacturer or the
Agency, there is no need for a statutory exception on the basis that a
defect is inconsequential to motor vehicle safety. And since a defect
determination involves a finding that the defect poses an unreasonable
risk to safety, asking the agency to make a determination that a defect
posing an unreasonable risk to safety is inconsequential has heretofore
been almost unexplored.\101\
---------------------------------------------------------------------------

    \99\ Id. 30118(d), 30120(h).
    \100\ Id. 30118(c)(1).
    \101\ NHTSA notes that the current petition is different in that
the inflators were declared defective by the supplier of the airbag,
and that GM's defect notice was filed in response to the supplier's
notice.
---------------------------------------------------------------------------

    Given this statutory context, a manufacturer bears a heavy burden
in petitioning NHTSA to determine that a defect related to motor
vehicle safety (which necessarily involves an unreasonable risk of an
accident, or death or injury in an accident) is nevertheless
inconsequential to motor vehicle safety. In accordance with the plain
meaning of ``inconsequential,'' the manufacturer must show that a risk
posed by a defect is not important or capable of being ignored. This
appropriately describes the actual consequence of granting a petition
as well. The manufacturer would be relieved of its statutory
obligations to notify vehicle owners and remedy the defect, and
effectively ignore the defect as unimportant from a safety perspective.
Accordingly, the threshold of evidence necessary for a manufacturer to
carry its burden of persuasion that a defect is inconsequential to
motor vehicle safety is difficult to satisfy. This is particularly true
where the defect involves a potential failure of safety-critical
equipment, as is the case here.
    The Agency necessarily determines whether a defect or noncompliance
is inconsequential to motor vehicle safety based on the specific facts
before it. The scarcity of defect-related inconsequentiality petitions
over the course of the Agency's history reflects the heavy burden of
persuasion as well as the general understanding among regulated
entities that the grant of such relief would be quite rare. The Agency
has recognized this explicitly in the past. For example, in 2002, NHTSA
stated that ``[a]lthough NHTSA's empowering statute alludes to the
possibility of an inconsequentiality determination with regard to a
defect, the granting of such a petition would be highly unusual.''
\102\
---------------------------------------------------------------------------

    \102\ Letter from J. Glassman, NHTSA, to V. Kroll, Adaptive
Driving Alliance (Sept. 23, 2002), https://www.nhtsa.gov/interpretations/ada3.
---------------------------------------------------------------------------

    Of the three known occasions in which the Agency has previously
considered petitions contending that a defect is inconsequential to
motor vehicle safety, the Agency has granted only one of the petitions,
nearly three decades ago, in a vastly different set of
circumstances.\103\ In that case, the defect was a typographical error
in the vehicle's gross vehicle weight rating (GVWR) that had no impact
on the actual ability of the vehicle to carry an appropriate load.
NHTSA granted a motorcycle manufacturer's petition, finding that a
defect was inconsequential to motor vehicle safety where the GVWR was
erroneously described as only 60 lbs., which error was readily apparent
to the motorcycle operator based upon both common sense and the fact
that the 330 lbs. front axle rating and 540 lbs. rear axle rating were
listed directly below the GVWR on the same label.\104\ Moreover, the
error did not actually impact the ability of the motorcycle to carry
the weight for which it was designed.\105\
---------------------------------------------------------------------------

    \103\ See id.
    \104\ Suzuki Motor Co., Ltd.; Grant of Petition for
Inconsequential Defect, 47 FR 41458, 41459 (Sept. 20,1982) and 48 FR
27635, 27635 (June 16, 1983).
    \105\ Id.
---------------------------------------------------------------------------

    On the other hand, NHTSA denied another petition concerning a
vehicle's weight label where there was a potential safety impact. NHTSA
denied that petition from National Coach Corporation on the basis that
the rear gross axle weight rating (RGAWR) for its buses was too low and
could lead to overloading of the rear axle if the buses were fully
loaded with passengers.\106\ NHTSA rejected arguments that most of the
buses were not used in situations where they were fully loaded with
passengers and that there were no complaints.\107\ NHTSA noted that its
Office of Defects Investigation had conducted numerous investigations
concerning overloading of suspensions that resulted in recalls, that
other manufacturers had conducted recalls for similar issues in the
past, and that, even if current owners were aware of the issue,
subsequent owners were unlikely to be aware absent a recall.\108\
---------------------------------------------------------------------------

    \106\ Nat'l Coach Corp.; Denial of Petition for Inconsequential
[Defect], 47 FR 49517, 49517 (Nov. 1, 1982). NHTSA's denial was
erroneously titled ``Denial of Petition for Inconsequential
Noncompliance;'' the discussion actually addressed the issue as a
defect. See id.; see also Nat'l Coach Corp.; Receipt of Petition for
Inconsequential Defect, 47 FR 4190 (Jan. 28, 1982).
    \107\ Id. at 49517-18.
    \108\ Id. at 49518.
---------------------------------------------------------------------------

    NHTSA also denied a petition asserting that a defect was
inconsequential to motor vehicle safety where the defect involved
premature corrosion of critical structure components (the vehicle's
undercarriage), which could result in a crash or loss of vehicle
control.\109\ Fiat filed the petition preemptively, following NHTSA's
initial decision that

certain Fiat vehicles contained a safety-related defect.\110\ In
support of its petition, Fiat argued that no crashes or injuries
resulted from components that failed due to corrosion, and that owners
exercising due diligence had adequate warning of the existence of the
defect.\111\ NHTSA rejected those arguments and both finalized its
determination that certain vehicles contained a safety-related defect
(i.e., ordered a recall) and found that the defect was not
inconsequential to motor vehicle safety.\112\ NHTSA explained that the
absence of crashes or injuries was not dispositive: ``the possibility
of an injury or accident can reasonably be inferred from the nature of
the component involved.'' \113\ NHTSA also noted that the failure mode
was identical to another population of vehicles for which Fiat was
carrying out a recall.\114\ The Agency rejected the argument that there
was adequate warning to vehicle owners, explaining that the average
owner does not inspect the underbody of a car and interior corrosion
may not be visible.\115\
---------------------------------------------------------------------------

    \109\ Final Determination & Order Regarding Safety Related
Defects in the 1971 Fiat Model 850 and the 1970-74 Fiat Model 124
Automobiles Imported and Distributed by Fiat Motors of N. Am., Inc.;
Ruling on Petition of Inconsequentiality, 45 FR 2134, 2137, 41 (Jan.
10, 1980).
    \110\ Fiat Motors of N. Am., Inc.; Receipt of Petition for
Determination of Inconsequential Defect, 44 FR 60193, 60193 (Oct.
18, 1979); Fiat Motors Corp. of N. Am.; Receipt of Petition for
Determination of Inconsequential Defect, 44 FR 12793, 12793 (Mar. 8,
1979).
    \111\ See, e.g., 45 FR 2134, 2141 (Jan. 10, 1980).
    \112\ Final Determination & Order Regarding Safety Related
Defects in the 1971 Fiat Model 850 and the 1970-74 Fiat Model 124
Automobiles Imported and Distributed by Fiat Motors of N. Am., Inc.;
Ruling on Petition of Inconsequentiality, 45 FR 2137-41 (Jan. 10,
1980). Fiat also agreed to a recall of certain of the vehicles, and
NHTSA found that Fiat did not reasonably meet the statutory recall
remedy requirements. Id. at 2134-37.
    \113\ Id. at 2139.
    \114\ Id.
    \115\ Id. at 2140.
---------------------------------------------------------------------------

    Agency practice over several decades therefore shows that
inconsequentiality petitions are rarely filed in the defect context,
and virtually never granted. Nonetheless, in light of the importance of
the issues here, and the fact that GM's defect notification was filed
in response to the notification provided by their supplier, the Agency
also considered the potential usefulness of the Agency's precedent on
noncompliance. The same legal standard--``inconsequential to motor
vehicle safety''--applies to both defects and noncompliances.\116\
---------------------------------------------------------------------------

    \116\ 49 U.S.C. 30118(d), 30120(h).
---------------------------------------------------------------------------

    In the noncompliance context, in some instances, NHTSA has
determined that a manufacturer met its burden of demonstrating that a
noncompliance was inconsequential to safety. For example, labels
intended to provide safety advice to an occupant that may have a
misspelled word, or may be printed in the wrong format or the wrong
type size, have been deemed inconsequential where they should not cause
any misunderstanding, especially where other sources of correct
information are available.\117\ These decisions are similar in nature
to the lone instance where NHTSA granted a petition for an
inconsequential defect, as discussed above.
---------------------------------------------------------------------------

    \117\ See, e.g., Gen. Motors, LLC.; cf. Grant of Petition for
Decision of Inconsequential Noncompliance, 81 FR 92963 (Dec. 20,
2016). By contrast, in Michelin, we reached the opposite conclusion
under different facts. There, the defect was a failure to mark the
maximum load and corresponding inflation pressure in both Metric and
English units on the sidewall of the tires. Michelin N. America,
Inc.; Denial of Petition for Decision of Inconsequential
Noncompliance, 82 FR 41678 (Sept. 1, 2017).
---------------------------------------------------------------------------

    However, the burden of establishing the inconsequentiality of a
failure to comply with a performance requirement in a standard--as
opposed to a labeling requirement--is more substantial and difficult to
meet. Accordingly, the Agency has not found many such noncompliances
inconsequential.\118\ Potential performance failures of safety-critical
equipment, like seat belts or air bags, are rarely deemed
inconsequential.
---------------------------------------------------------------------------

    \118\ Cf. Gen. Motors Corporation; Ruling on Petition for
Determination of Inconsequential Noncompliance, 69 FR 19897, 19899
(Apr. 14, 2004) (citing prior cases where noncompliance was expected
to be imperceptible, or nearly so, to vehicle occupants or
approaching drivers).
---------------------------------------------------------------------------

    An important issue to consider in determining inconsequentiality
based upon NHTSA's prior decisions on noncompliance issues was the
safety risk to individuals who experience the type of event against
which the recall would otherwise protect.\119\ NHTSA also does not
consider the absence of complaints or injuries to show that the issue
is inconsequential to safety.\120\ ``Most importantly, the absence of a
complaint does not mean there have not been any safety issues, nor does
it mean that there will not be safety issues in the future.'' \121\
``[T]he fact that in past reported cases good luck and swift reaction
have prevented many serious injuries does not mean that good luck will
continue to work.'' \122\
---------------------------------------------------------------------------

    \119\ See Gen. Motors, LLC; Grant of Petition for Decision of
Inconsequential Noncompliance, 78 FR 35355 (June 12, 2013) (finding
noncompliance had no effect on occupant safety because it had no
effect on the proper operation of the occupant classification system
and the correct deployment of an air bag); Osram Sylvania Prods.
Inc.; Grant of Petition for Decision of Inconsequential
Noncompliance, 78 FR 46000 (July 30, 2013) (finding occupant using
noncompliant light source would not be exposed to significantly
greater risk than occupant using similar compliant light source).
    \120\ See Combi USA Inc., Denial of Petition for Decision of
Inconsequential Noncompliance, 78 FR 71028, 71030 (Nov. 27, 2013).
    \121\ Morgan 3 Wheeler Ltd.; Denial of Petition for Decision of
Inconsequential Noncompliance, 81 FR 21663, 21666 (Apr. 12, 2016).
    \122\ United States v. Gen. Motors Corp., 565 F.2d 754, 759
(D.C. Cir. 1977) (finding defect poses an unreasonable risk when it
``results in hazards as potentially dangerous as sudden engine fire,
and where there is no dispute that at least some such hazards, in
this case fires, can definitely be expected to occur in the
future'').
---------------------------------------------------------------------------

    Arguments that only a small number of vehicles or items of motor
vehicle equipment are affected have also not justified granting an
inconsequentiality petition.\123\ Similarly, NHTSA has rejected
petitions based on the assertion that only a small percentage of
vehicles or items of equipment are likely to actually exhibit a
noncompliance. The percentage of potential occupants that could be
adversely affected by a noncompliance does not determine the question
of inconsequentiality. Rather, the issue to consider is the consequence
to an occupant who is exposed to the consequence of that
noncompliance.\124\ These considerations are also relevant when
considering whether a defect is inconsequential to motor vehicle
safety.
---------------------------------------------------------------------------

    \123\ See Mercedes-Benz, U.S.A., L.L.C.; Denial of Application
for Decision of Inconsequential Noncompliance, 66 FR 38342 (July 23,
2001) (rejecting argument that noncompliance was inconsequential
because of the small number of vehicles affected); Aston Martin
Lagonda Ltd.; Denial of Petition for Decision of Inconsequential
Noncompliance, 81 FR 41370 (June 24, 2016) (noting that situations
involving individuals trapped in motor vehicles--while infrequent--
are consequential to safety); Morgan 3 Wheeler Ltd.; Denial of
Petition for Decision of Inconsequential Noncompliance, 81 FR 21663,
21664 (Apr. 12, 2016) (rejecting argument that petition should be
granted because the vehicle was produced in very low numbers and
likely to be operated on a limited basis).
    \124\ See Gen. Motors Corp.; Ruling on Petition for
Determination of Inconsequential Noncompliance, 69 FR 19897, 19900
(Apr. 14, 2004); Cosco Inc.; Denial of Application for Decision of
Inconsequential Noncompliance, 64 FR 29408, 29409 (June 1, 1999).
---------------------------------------------------------------------------

B. Information Before the Agency

    In support of its Petition, GM submitted thousands of pages of
information and data, including work by OATK and Cornerstone on GM's
behalf, which is summarized above and further discussed below. In
addition, the Agency retained Harold R. Blomquist, Ph.D. to consult on
scientific issues related to NHTSA's ongoing investigation into Takata
PSAN air bag inflators. As part of the Agency's review of GM's
Petition, Dr. Blomquist attended presentations by GM made to the Agency
and provided a technical assessment of the information provided by GM.
    Dr. Blomquist is a highly-regarded and well-qualified expert in the
automotive engineering field, who has spent most of his career focused
on

issues related to ``the design of energetic solid materials such as
propellants, pyrotechnics, explosives and gas generants (propellants)
for missile systems and automotive air bag applications.'' \125\ After
earning his Ph.D. from Duke University in 1980, Dr. Blomquist began
working in the rocket industry for Aerojet Strategic Propulsion
Corporation and Olin Rocket Research Corporation, where he led
propulsion research and development (``R&D'') activities.\126\
---------------------------------------------------------------------------

    \125\ 2020 Blomquist Report at para. 8.
    \126\ Id. at para. 9.
---------------------------------------------------------------------------

    After ten years in the rocket industry, Dr. Blomquist transitioned
to TRW Automotive in 1990, where the focus of his work was automotive
air bag technologies.\127\ For the next twenty years, Dr. Blomquist's
work at TRW included inflator design research and energetic materials
(propellant, booster, and autoignitiation) formulation R&D. Notably,
during the 1990s, Dr. Blomquist worked on replacing TRW's azide-based
propellant technology, through which he worked with inflators with PSAN
oxidizers, like the Takata inflators at issue with this petition.\128\
---------------------------------------------------------------------------

    \127\ Id.
    \128\ Id. at paras. 13-15.
---------------------------------------------------------------------------

    Because of his work at TRW, Dr. Blomquist holds twenty-five air-bag
related patents and was honored twice with product innovation awards
related to airbag systems.\129\ Further, Dr. Blomquist has published on
the subject of airbags and propellants, including ``a technical paper
describing PSAN-based propellant and corresponding inflator [which was]
presented at the national meeting of the American Institute of Chemical
Engineers.'' \130\ Dr. Blomquist's experience is more fully set forth
in his Report, along with his assessments and findings concerning GM's
petition. Dr. Blomquist's report is available in docket no. NHTSA-2016-
0124.
---------------------------------------------------------------------------

    \129\ Id. at para. 10.
    \130\ Id. at para. 20.
---------------------------------------------------------------------------

    Dr. Blomquist reviewed the technical data provided by GM in support
of its Petition, as well as information available to the Agency through
its ongoing investigation in EA15-001, including presentations and
information submitted by TK Global.\131\ Ultimately, Dr. Blomquist
concluded that GM's claim that design and environmental features render
the GMT900 inflators less likely to rupture is unfounded.\132\ Many of
GM's enumerated features that allegedly make the GMT900 inflators
uniquely resilient to rupture are, in fact, not unique to the GMT900
inflators, and other inflators that possess those characteristics have
experienced field and testing ruptures, as well as abnormally high-
pressure events indicative of propellant degradation.\133\ Further,
ballistic testing results for the GMT900 inflators that are subject to
this petition include abnormally high-pressure events indicative of
potential future rupture risk.\134\ These findings illustrate that GM's
inflators have a similar, if not identical, degradation continuum to
that of the other Takata non-desiccated PSAN inflators, and test
results from field-aged inflators are consistent with gradual
propellant degradation and expected increasing high-pressure
deployments.\135\
---------------------------------------------------------------------------

    \131\ Some information reviewed by Dr. Blomquist--including
certain information submitted by GM--is subject to a request for
confidential treatment, and is not publicly available.
    \132\ 2020 Blomquist Report at paras. 253-56; see generally id.
at 253-74 (Conclusions).
    \133\ See id. at paras. 259, 263.
    \134\ Id. at paras. 262, 263a.
    \135\ Id. at paras. 262, 269.
---------------------------------------------------------------------------

    In addition, Dr. Blomquist found that the OATK Aging Study--which
forms the basis for most of GM's supporting arguments--did not
replicate real-world conditions.\136\ ``Similarly, OATK's predictive
model is anchored in key ways to the data derived from OATK's Aging
Study, so any weaknesses observed in the Aging Study may explain the
Model's inability to predict observed high pressure events and ruptures
of field aged inflators.'' \137\ Dr. Blomquist concluded, inter alia,
that the inflators used in GM's vehicles under Petition here--like
other Takata non-desiccated PSAN inflators--are susceptible to
propellant degradation as built, and to risk of rupture.\138\
---------------------------------------------------------------------------

    \136\ Id. at para. 271.
    \137\ Id. at para. 272.
    \138\ Id. at paras. 273.
---------------------------------------------------------------------------

    The Agency has independently reviewed all of the information
submitted by GM and TK Global on this matter, as well as Dr.
Blomquist's Report. Based upon this information, and applying its
expert judgment as the Agency charged with overseeing motor vehicle
safety, NHTSA has determined that GM has not demonstrated that the
defect is inconsequential to safety in the GMT900 vehicles. The
Petition is therefore denied, for the reasons set forth in more detail
below.

C. Response to GM's Supporting Information & Analyses

    Rather than focusing on the consequence to an occupant in the event
of an inflator rupture,\139\ GM instead seeks to show that the GMT900
inflators are not at risk of rupture, contending that GMT900 inflators
are ``more resilient'' to rupture than other Takata PSAN
inflators.\140\ As discussed above, in support of this argument, GM
points to unique inflator design differences and unique vehicle
features, as well as testing and field data, aging studies, predictive
modeling, risk assessments, and the notion that dealer repairs create a
potential risk. GM does not discuss the consequence to an occupant in
the event of an inflator rupture, and the information provided by GM
does not persuasively demonstrate any specific or unique resiliency to
propellant degradation or inflator rupture in GMT900 inflators. And, as
discussed previously, field-return testing of GMT900 inflators show
elevated deployment pressures indicative of propellant degradation and
future rupture risk.
---------------------------------------------------------------------------

    \139\ In fact, as GM has never observed or induced a rupture of
a GMT900 inflator, GM affirmatively stated it could not determine
the safety consequence of an inflator rupture in a GMT900 vehicle.
See GM's September 2017 Response at 7.
    \140\ See, e.g., Fourth Petition at 16; GM's August 23, 2017
Presentation at 33.
---------------------------------------------------------------------------

1. Unique Inflator Design Differences and Vehicle Features
    GM has not demonstrated that any of the features described above--
either alone or in conjunction with other features or factors--prevents
propellant degradation or renders the defect in GMT900 inflators
inconsequential to safety.\141\ In fact, as outlined below, other
Takata inflators with similar design features have experienced ruptures
and high-pressure deployments. Similarly, vehicles with lower or
similar peak temperatures have also experienced ruptures and high-
pressure deployments. Thus, there is no persuasive evidence that GM's
claimed ``unique'' design advantages lead to a reduced risk of inflator
rupture.\142\
---------------------------------------------------------------------------

    \141\ GM's assertion that strict adherence to the USCAR air bag
performance standards ``resulted in [GM] inflators with increased
inflator-structural integrity, better ballistic performance, and
greater resistance to moisture'' does not change this conclusion.
See Third Petition at 6. As noted above, USCAR standards are
utilized across the industry, and adherence to those standards is
not particular to the GMT900 inflators at issue. Moreover, gradual
density reduction in both the YD and YP inflator variants
demonstrate the GMT900 inflators are drafting out of conformance to
SAE/USCAR 24-2 safety requirements. 2020 Blomquist Report at para.
265.
    \142\ See id. at para. 233.
---------------------------------------------------------------------------

    Thinner Propellant Wafers. GM claims that the thinner (8mm)
propellant wafers used in the GMT900 inflators have more predictable
ballistic properties than thicker (11mm) wafers used in many other
Takata PSAN inflator variants, which ``create less

excess surface area as they degrade.'' \143\ As a result, GM contends
that the thinner propellant wafers used in the GMT900 vehicles age more
slowly and burn more efficiently than thicker propellant wafers,
resulting in a reduced risk of inflator rupture.\144\ In support of its
argument, GM relies on two comparison inflator variants--the SPI AJ and
the PSPI-L FD.\145\ Both variants use primarily 11mm wafers, are
commonly installed in vehicle platforms with higher peak temperatures,
and have been shown in Takata test and field data to age faster and/or
show ruptures and abnormal pressures more often than many other
variants.\146\
---------------------------------------------------------------------------

    \143\ Fourth Petition at 6-7; see Third Petition at 6.
    \144\ See Third Petition at 6; Fourth Petition at 6-7.
    \145\ See GM's August 23, 2017 Presentation at 44-45.
    \146\ 2020 Blomquist Report at paras. 60-63, 196.
---------------------------------------------------------------------------

    GM's claim that 8 mm wafers age more slowly than 11 mm wafers is
not supported by the results of the OATK Aging Study or by testing data
obtained on field aged inflators. There was no significant difference
in wafer growth between 8 mm wafers and 11 mm wafers for the inflators
in the OATK Aging Study with as-built moisture levels; accordingly, at
comparable moisture and temperature conditions, the growth rates of the
two sized wafers are essentially the same.\147\ At most, the evidence
tends to show that the GMT900 inflators age more slowly than the worst
performing inflator variants.\148\
---------------------------------------------------------------------------

    \147\ Id. at para. 212.
    \148\ See id. at paras. 195, 209-13.
---------------------------------------------------------------------------

    Moreover, the use of thinner wafers is not unique to the GMT900
inflator variants, as 8 mm wafers are used in at least twenty-one other
Takata PSPI inflator variants.\149\ Those non-GM variants using 8 mm
wafers--including certain variants that share many of the attributes of
the GMT900 inflators--are also susceptible to propellant degradation,
and have experienced ruptures and abnormally high pressures during
ballistic testing.\150\ Furthermore, GM's contention is undermined by
ballistic testing conducted on the YP and YD inflator variants used in
the GMT900 vehicles. Thus far, four YD and YP inflators have
experienced abnormally high peak pressures consistent with propellant
degradation, including one field-returned YP inflator that recorded a
91 MPa peak internal pressure--a near rupture.\151\ As more time
passes, it is reasonable to anticipate that this trend will continue--
as has been seen with non-desiccated PSAN inflators generally.
---------------------------------------------------------------------------

    \149\ See id. at para. 263a.
    \150\ See id. at paras. 194, 263a, 273; GM's August 23, 2017
Presentation at 43-45, 171-178.
    \151\ GM's February 12, 2018 Presentation at 5-18; GM's April 9,
2018 Presentation at 14-15; GM's June 8, 2018 Presentation at 115;
2020 Blomquist Report at paras. 96-99, 173, 246-49, 263a.
---------------------------------------------------------------------------

    Larger Vent Area. GM claims that a greater vent-area-to-propellant-
mass ratio provides for more efficient burning and deployment of the
GMT900 inflators, resulting in a reduced risk of inflator rupture.\152\
The vent area is not variable in any Takata inflator; that is, the vent
area does not change during air bag deployment.\153\ While the larger
vent size of a GMT900 inflator might provide for more efficient burning
during normal air bag deployment, the same cannot be said during an
abnormal deployment of a defective PSAN inflator.\154\ Given the sudden
increase in burning surface-area that may occur during an abnormal
deployment of a defective PSAN inflator, the vent area may still be
overwhelmed causing steep internal pressure increases.\155\ Because the
vent area of the GMT900 inflators does not, and cannot, change to
address the steep internal pressure increases that occur when a
defective PSAN inflator abnormally deploys, it does not render the
inflators resistant to rupture.\156\
---------------------------------------------------------------------------

    \152\ Fourth Petition at 7. While mass (density) is relevant to
propellant degradation, it is the vent-area-to-burning-surface-area
ratio that is most relevant to GM's claims here. See 2020 Blomquist
Report at para. 65.
    \153\ See 2020 Blomquist Report at para. 65.
    \154\ See id. at paras. 65, 215-22.
    \155\ See id. at paras. 218-20, 263c.
    \156\ See id. at para. 218, 263c.
---------------------------------------------------------------------------

    Steel Endcaps. GM claims that use of a steel endcap on the GMT900
inflators better protects the PSAN propellant from moisture by creating
an improved hermetic seal compared to the aluminum endcaps used on
other Takata PSAN inflators.\157\ However, GM provided no evidence to
support this argument or its statement that steel endcaps improved the
inflators ``resistance to high-internal pressures'' \158\ beyond an
OATK investigation that pre-dated the petition--which, in any event,
only illustrated that steel endcaps provide no measurable advantage
over other variants with respect to moisture intrusion.\159\
---------------------------------------------------------------------------

    \157\ Fourth Petition at 7.
    \158\ Id.
    \159\ See 2020 Blomquist Report at paras. 213-214, 263b.
---------------------------------------------------------------------------

    Other Design Differences. As noted above, GM observed several other
design differences in its presentations to NHTSA, but did not reference
or elaborate on these differences in their Petition documents. In any
event, the mere mention of these differences--tablets in a cup (for YP
variants), the incorporation of a ceramic cushion (also for YP
variants), and the incorporation of a bulkhead disk with an anvil (for
YD variants)--are unpersuasive.
    GM provided no data demonstrating that the behavior of tablets
during deployment is a major or secondary factor in the root cause of
ruptures arising from degradation, and density data in the OATK aging
study ``is nearly flat for all three variants at as-built and flat at
mid-level moisture levels at all peak temperatures.'' \160\ GM also did
not provide any information supporting the relevance of a ceramic
cushion to mitigating inflator rupture or abnormally high-pressure
deployments.\161\ And data provided by GM showed that, for inflator
variants with a bulkhead anvil, the moisture gain in the booster
propellant did not significantly change the main propellant moisture
levels in inflators, which varied in the same small range across all
inflator variants tested in the OATK Aging Study.\162\ Since the
bulkhead-anvil feature had no effect on the main propellant moisture
levels--which would be relevant to propellant degradation, the cause of
inflator rupture--GM has not demonstrated that this design
characteristic results in a reduced risk of rupture.\163\
---------------------------------------------------------------------------

    \160\ Id. at paras. 70, 223, 263d.
    \161\ See id. at paras. 71, 224, 263e.
    \162\ Id. at paras. 225-26, 263f.
    \163\ See id.
---------------------------------------------------------------------------

    Larger Cabin Volume & Solar Absorbing Glass. GM claims that the
GMT900 vehicles have larger cabin volumes than other vehicles equipped
with Takata PSAN inflators, and are all equipped with solar-absorbing
glass windshields and side glass, which results in lower internal
vehicle temperatures and thus a reduced risk of inflator rupture.\164\
However, GM did not provide any data demonstrating the influence of
larger cabin volume on peak temperatures independent of temperature
band, or any data specific to how solar absorbing glass affects
interior vehicle temperatures.\165\ In fact, at least one non-GM
vehicle has a much smaller cabin, yet has a temperature profile lower
than that claimed for the GMT900 vehicles; nonetheless, that vehicle--a
mid-sized pick-up truck--experienced an inflator rupture.\166\ Further,
GM did not demonstrate that these alleged lower internal vehicle
temperatures rendered the GMT900

inflators more resilient to rupture. Vehicles with similar, if not
lower, peak vehicle temperatures have experienced inflator rupture and
abnormally high-pressure deployments--including that of an inflator
variant that is nearly identical to the GMT900 YP inflator
variant.\167\ Additionally, as explained below, at least four inflators
from GMT900 vehicles have experienced abnormally high internal pressure
deployments indicative of propellant degradation and increased risk of
rupture. Given the evidence of degradation in GMT900 inflators and
inflator variants that possess the same design features, the evidence
does not demonstrate that the GMT900 vehicle environment
characteristics appreciably reduce the risk of inflator rupture for
defective Takata non-desiccated PSAN inflators.
---------------------------------------------------------------------------

    \164\ First Petition at 12; Second Petition at 11-12; Third
Petition at 7-8; Fourth Petition at 7.
    \165\ See 2020 Blomquist Report at paras. 73-74, 228, 230.
    \166\ See id. at para. 74.
    \167\ See id. at paras. 74, 200, 263g; GM's August 23, 2017
Presentation at 45.
---------------------------------------------------------------------------

    GM further provided data from ballistic testing, field data, and
temperature and aging studies, as well as outputs from a predictive
model purporting to show that the GMT900 inflators pose a lower risk of
rupture. As outlined below there are a number of compounding concerns
with the information and analyses presented that render GM's arguments
unpersuasive.
2. Testing & Field Inflator Analyses
    Testing by Takata. In its Third Petition, GM claims that none of
the GMT900 field return inflators collected and sent to Takata for
ballistic testing and analysis ruptured or demonstrated elevated
deployment pressure or other signs of abnormal deployment.\168\ In its
Fourth Petition, GM amended this claim to only assert that none of the
field return inflators had ruptured.\169\ This change may be in
response to MEAF data indicating that at least four inflators recovered
from GMT900 vehicles in Zone A experienced abnormally high pressure
during ballistic testing: Three YP variant inflators and one YD
inflator returned from MY 2007 GMT900 vehicles experienced high-
pressure deployments. One of these even reached a pressure of 91 MPa: A
near rupture.\170\ It is true that, at present, there is no known
incident of a rupture of a GMT900 inflator during ballistic testing
having occurred during the pendency of GM's petition. However, this
does not show that the defect here is inconsequential to safety.
Instead, the testing results indicate that these inflators--even
encompassing all of the design ``advantages'' claimed by GM--have and
will continue to suffer propellant degradation in a manner similar to
the other non-desiccated PSAN inflators.\171\
---------------------------------------------------------------------------

    \168\ Third Petition at 13.
    \169\ Fourth Petition at 12.
    \170\ See 2020 Blomquist Report at paras. 246-49.
    \171\ See id. at paras. 246-49, 267-69, 250-52, 273-74.
---------------------------------------------------------------------------

    GM sought to distinguish the YP inflator that experienced the near-
rupture ballistic result by categorizing it as a ``Gen1'' YP inflator
that differs from ``Gen2'' YP inflators based on a shift from
propellant tablets to granules, a minor decrease in the amount of
tablet propellant weight, the use of a cup instead of a sleeve to hold
the propellant tablets, and the addition of the ceramic cushions.\172\
As discussed above, GM has not shown that these particular features
prevent propellant degradation or provide special resiliency against
inflator rupture.\173\ Both Gen1 and Gen2 use the same number of 8 mm
wafers, have the same vent area, and experience the same in-vehicle
environmental conditions; yet, the 91 MPa deployment is clear evidence
that the YP variant is experiencing propellant degradation that leads
to ruptures and/or abnormally high internal inflator pressures.\174\ In
addition, the nearly identical SPI DH/MG inflator variant--which shares
most design attributes, the same diameter growth rate, and the same
peak vehicle temperature band--exhibited a rupture rate of 1 per 6,771
during ballistic testing.\175\ GM has not explained how these ballistic
test results can be reconciled with its position that the GMT900
inflators will not rupture ``within even unrealistically conservative
vehicle-service life estimates.'' \176\ Given the severity of a rupture
outcome, the observed propellant degradation in the GMT900 inflators
and inflator variants with similar (if not identical) characteristics
cannot be ignored; these test results are consistent with the notion
that the GMT900 inflators have and will continue to suffer propellant
degradation in a manner similar to other non-desiccated PSAN inflators.
---------------------------------------------------------------------------

    \172\ See GM Presentation to NHTSA February 12, 2018, 5-18; 2020
Blomquist Report at paras. 97, 247.
    \173\ See also 2020 Blomquist Report at paras. 97, 247, 267.
    \174\ See id. at paras. 247-48.
    \175\ See id. at paras. 200, 248-49.
    \176\ See Fourth Petition at 4.
---------------------------------------------------------------------------

    Further, NHTSA has concerns about the size of the ballistic-testing
population. GM asserts that in deploying over 4,200 inflators taken
from GMT900 vehicles, none have ruptured.\177\ By comparison, the total
GMT900 population under consideration is nearly 5.9 million vehicles.
Thus, the number of ballistic tests conducted is approximately 0.07% of
the total GMT900 population. Even when only comparing the number of
inflators tested to the approximately 2 million 2007 and 2008 MY GMT900
vehicles under Petition (the oldest GMT900 vehicles covered by the
Petition), the number of ballistic tests conducted is approximately
0.21% of that total population. By comparison, for example, that
percentage of the GMT900 population tested is smaller than the
percentage of inflators tested, as of November 2019, in a population of
a non-GM mid-sized pick-up vehicle--1.81%--with one observed test
rupture. Rupture risk in non-desiccated PSAN inflators increases with
age/exposure; although testing may not yet have resulted in a rupture,
that does not mean that ruptures will not occur in the future.
---------------------------------------------------------------------------

    \177\ Id. at 12.
---------------------------------------------------------------------------

    Stress-Strength Interference Analysis. In the First and Second
Petitions, GM includes a ``stress-strength interference analysis''
that, it contended, suggests that propellant in MY 2007 and 2008 GMT900
inflators had not degraded to a sufficient degree to create a rupture
risk.\178\ GM explains stress-strength interference analysis as the
plotting of curves on a graph related to the diameter of field-returned
YP and YD inflators and the diameter of non-GM inflators that have
ruptured during ballistic testing; the amount of overlap between the
two curves ``represents the probability of rupture in a particular
group of inflators.'' \179\ GM did not discuss this assessment in its
Third or Fourth Petitions, appearing to have largely abandoned it in
favor of the OATK Aging Study and OATK Model discussed below. In any
event, NHTSA does not find it persuasive or determinative on the
question of inconsequentiality.
---------------------------------------------------------------------------

    \178\ First Petition at 15-17; Second Petition at 15-17.
    \179\ Second Petition at 16.
---------------------------------------------------------------------------

    First, this analysis only measures the outside diameter of
propellant wafers. While wafer growth and diameter are an indicator of
propellant degradation, they are not the only indicator that
degradation has occurred. As seen in inflators returned from the field,
degradation is evidenced by the formation of pores or fissures in the
propellant wafers, as well as changes in the propellant wafer density
and diameter.\180\ Therefore, reliance on wafer growth alone is of
limited utility.

And second, this analysis focused on propellant with an average age of
eight to nine years. As the vast majority of inflators take longer than
that time period to experience propellant degradation sufficient for
rupture, looking at inflators of this age is also of limited
value.\181\
---------------------------------------------------------------------------

    \180\ See 2020 Blomquist Report at paras. 42, 44-45, 53.
    \181\ See id. at paras. 234, 266 (noting also the ``wide
variation of vehicle utilization by consumers'' that ``makes the
analysis difficult to use with confidence''). Indeed, GM's analysis
did not address the rupture of an inflator variant with a wafer-
growth rate similar to the YP variant, which ruptured at a field age
of 11.6 years in Florida. Id. at para. 235.
---------------------------------------------------------------------------

    Crash Deployment Estimates. In the Fourth Petition, GM estimates
that 66,894 Takata passenger air bag inflators have deployed in GMT900
vehicles without a reported rupture.\182\ It is true that during the
pendency of GM's petition, there is no known incident of a rupture of a
GMT900 inflator in the field. However, that a rupture has not yet
occurred or been reported does not mean that a rupture will not occur
in the future. This is particularly relevant in the case of Takata non-
desiccated PSAN inflators, where the risk of rupture increases as
inflators age and have more exposure to heat and humidity, and in the
HAH and Zone A geographic areas described above, first becomes manifest
after more than ten years in service.
---------------------------------------------------------------------------

    \182\ Fourth Petition at 12.
---------------------------------------------------------------------------

    Moreover, GM's assertions based on ``rupture-free'' crash
deployment estimates provide no support for the notion that, in the
event of a GMT900 inflator rupture, the result will be inconsequential
to safety. As noted above, when taking into consideration the Agency's
noncompliance precedent, the likelihood of a rupture is not the only
relevant factor here. Indeed, an important factor is also the severity
of the consequence of the defect were it to occur--i.e., the safety
risk to an occupant who is exposed to an inflator rupture. The known
consequence of a rupturing Takata non-desiccated PSAN air bag inflators
is quite severe: The spraying of metal shrapnel toward vehicle
occupants. GM does not provide any information to suggest that result
would be any different were such an inflator to rupture in a GMT900
vehicle.
    Even if GM's crash deployment estimates were informative, GM's
estimate does not prove a helpful comparison, as it includes both air
bag deployments in vehicles when they were new and unlikely to have
experienced propellant degradation, as well as deployments in vehicles
that were older and exposed to more temperature fluctuation and
environmental moisture (i.e., degradation). This estimate therefore
fails to account for the differences in the risk of rupture for new
vehicles and older vehicles. Additionally, in estimating the number of
past GMT900 air bag deployments GM utilized its own attrition model,
which resulted in a higher estimated number of deployments when
compared to estimates based on NHTSA's attrition models.\183\
---------------------------------------------------------------------------

    \183\ See GM's June 18, 2018 Presentation at 36. Had GM used
either the NHTSA 1995 or NHTSA-EPA 2016 attrition models when the
estimating the number of GMT900 air bag deployments that have
occurred in the past, GM would have estimated there to have been
fewer rupture-free deployments of its inflators in the field. See
NHTSA 1995 attrition model: Updated Vehicle Survivability and Travel
Mileage Schedules, NHTSA (Report Number: DOT HS 808 339) (Nov.
1995); NHTSA-EPA 2016 attrition model: EPA, CARB, & NHTSA, Draft
Technical Assessment Report: Midterm Evaluation of Light-Duty
Vehicle Greenhouse Gas Emission Standards and Corporate Average Fuel
Economy Standards for Model Years 2022-2025, EPA-420-D-16-900 July
2016, available at https://www.nhtsa.gov/staticfiles/rulemaking/pdf/cafe/Draft-TAR-Final.pdf.
---------------------------------------------------------------------------

    GM's estimate also is based only on reported ruptures, and
passenger air bag ruptures in the field may not always be reported (and
as such)--particularly if no passenger was present in the seat at the
time of rupture.
3. Aging Studies \184\
---------------------------------------------------------------------------

    \184\ As noted above, the GM Aging Study was intended to
demonstrate the short-term safety of GM's inflators while the
longer-term OATK Aging Study was conducted. In previously granting
GM additional time to provide evidence in support of its Petition,
the Agency found GM's reliance on, inter alia, GM's Aging Study, as
``probative evidence'' to support its claim of inconsequentiality.
81 FR 85681, 85684 (Nov. 28, 2016). The Agency only found this
information tended to support GM's petition ``at least with respect
to the short-term safety'' of the GMT900 inflators--it was not
sufficient to prove inconsequentiality. It does not appear that GM
directly relies on the results of the GM Aging Study in reaching its
conclusions, and therefore we do not analyze it here.
---------------------------------------------------------------------------

    The parameters of the OATK Aging Study are discussed above, and
while the Agency appreciates the work that went into the Study, the
Agency does not find the results of the Study persuasive for making an
inconsequentiality determination, for several reasons. As an initial
matter, certain inputs into the OATK Study are not sufficiently
reliable. Temperature data from the GM Temperature Study and the Atlas
Cabin Temperature Study informed the OATK Study's temperature cycles
and temperature bands.\185\ However, the GM Temperature Study included
only two of the twelve vehicle models covered by the Petition, and was
limited to only a handful of vehicles.\186\ The Atlas Cabin Temperature
Study also only utilized eleven non-GM vehicles and the Pontiac Vibe--
no GMT900 vehicles.\187\ In addition, for the GM Temperature Study, GM
reported on one, two, or three vehicles subjected to testing for
lengths of time that, at most, were only vaguely described--information
that is critical to determining the reliability of the study.\188\
Furthermore, the OATK Aging Study was based on analysis of fewer than
1,000 artificially aged inflators.\189\ As outlined above, such low
sample sizes (both in input from the temperature studies, and in the
number of inflators tested) limits confidence in the Aging Study
results, as well as any further study or model that relies on the
results of that Aging Study.
---------------------------------------------------------------------------

    \185\ 2020 Blomquist Report at para. 112.
    \186\ See GM's August 23, 2017 Presentation at 171.
    \187\ See id.; supra note 51 and accompanying text; 2020
Blomquist Report at para. 108.
    \188\ See 2020 Blomquist Report at para. 106.
    \189\ See First Petition, Ex.D (reflecting 891 inflators in
Statement of Work); GM's August 23, 2017 Presentation at 24 (``700+
Inflators'').
---------------------------------------------------------------------------

    Second, importantly, the OATK Aging Study did not appear to
accurately replicate the real-world degradation process observed to
occur in field-aged inflators.\190\ The underlying defect in the GMT900
inflators is a consequence of inflator propellant degradation. As seen
in inflators returned from the field, degradation is evidenced by the
formation of pores or fissures in the propellant wafers, as well as
changes in the propellant wafer density and diameter. While the Aging
Study did show changes in inflator wafer density and diameter, the
density changes observed during the Study did not replicate field aging
in inflators of very-high moisture content, nor did it replicate the
formation of pores or fissures seen in field-aged inflators.\191\
Additionally, the lab-aged inflators in the OATK Aging Study showed no
tendency to increase in pressure when wafers were above the diameter
were accelerated burning is expected,\192\ despite this result being
well-documented in most Takata inflator variants.\193\
---------------------------------------------------------------------------

    \190\ See 2020 Blomquist Report at paras. 236-45, 271.
    \191\ See id.
    \192\ GM August 23, 2017 Presentation at 17-18.
    \193\ 2020 Blomquist Report at para. 239.
---------------------------------------------------------------------------

    A third concern is the Aging Study's presumption that fifty-six
four hour cycles of laboratory accelerated aging is equivalent to one
year of aging in the field. It is the Agency's understanding that this
``equivalent year'' is derived from the number of days in Miami, FL
that GM presented as reaching

temperatures above 90[deg] F.\194\ However, this presumes that
propellant degradation only occurs on days or times that reach peak
temperatures of 90[deg] F, which is not correct as demonstrated by the
many inflators--both in the field and in testing--that have been
exposed to lower temperatures and still experienced propellant
degradation and inflator rupture.\195\ This test scheme also presumes
that the temperature cycle can be condensed from a twenty-four hour day
to four hours without compromising or altering the type of degradation
caused to the propellant.\196\ Based upon the information presented to
NHTSA, it does not appear that this was the case.
---------------------------------------------------------------------------

    \194\ Id. at para. 241; see generally GM's August 23, 2017
Presentation at 12.
    \195\ 2020 Blomquist Report at para. 241.
    \196\ Id. at para. 242; see id. at para.270.
---------------------------------------------------------------------------

    It is also appropriate to note here that GM's reliance on the use
of ``comparison inflators'' throughout its research (the SPI AJ and
PSPI-L FD--the latter of which was, for example, included in the OATK
Aging Study) to demonstrate the safety of the GMT900 inflators is
misplaced. First, arguing that the GMT900 inflators are ``safer'' than
other inflators with the same defect does not answer the question of
whether that defect is inconsequential to safety. Second, the selected
comparison inflators have been shown in Takata test and field data to
age faster and show ruptures and abnormal pressures more often than
many other variants.\197\ Additionally, unlike the GMT900 inflator
variants, the comparison variants use primarily 11mm wafers (as opposed
to 8mm wafers) and are installed on vehicles with higher peak
temperatures than what GM claims as the GMT900 peak temperature.\198\
Comparing GMT900 inflators to such disparate non-GM inflators does
little to quantify the risk posed by GM's inflators, and does not
demonstrate that the defect is inconsequential to safety.
---------------------------------------------------------------------------

    \197\ See id. at paras. 196-205.
    \198\ Id. at para. 196.
---------------------------------------------------------------------------

    And finally, analysis of other inflator variants that possess the
same attributes as the GMT900 inflators also weakens GM's claim that
the unique inflator design differences and vehicle environment of the
GMT900 vehicles render the GMT900 inflators more resilient to rupture.
The non-GM SPI DH/MG inflator variant is nearly identical to GM's YP
inflator in that it also uses 8mm wafers and enjoys a low peak inflator
surface temperature. Data showed that diameter measurements for the
(GM) YP inflators and (non-GM) DH/MG inflators were essentially the
same after field aging, reinforcing the similarity of the two
variants.\199\ Notably, the DH/MG inflator variant has exhibited a
rupture rate of 1 per of 6,771 ballistic tests. GM has not provided any
further, persuasive information that would explain how these ballistic
results can be reconciled with GM's position that its YP inflators will
not rupture ``within even unrealistically conservative vehicle-service
life estimates.'' \200\
---------------------------------------------------------------------------

    \199\ GM's August 23, 2017 presentation at 45; 2020 Blomquist
Report at para. 199 & n.13.
    \200\ See Fourth Petition at 4.
---------------------------------------------------------------------------

    Similarly, the non-GM PSPI-6 YB and PSPI-6 XG inflator variants,
which both use primarily 8mm wafers, can provide insight into GM's YD
inflators.\201\ The YB variant is used on two non-GM vehicle platforms,
one of which provides peak vehicle temperatures slightly lower than the
GMT900, and one of which provides peak vehicle temperatures slightly
higher than the GMT900. The non-GM platform using the YB variant that
experiences higher peak vehicle temperature conditions has experienced
at least one field rupture, three inflator ruptures during field-return
ballistic testing, and one abnormally high-pressure result during
ballistic testing.\202\ ``These results indicate that an 8mm wafer
inflator variant experiencing high peak inflator temperature in Zone A
can rupture at a similar age to the Vibe PSPI-L FD (with an 11mm wafer)
that GM used for comparison.'' \203\ Another non-GM vehicle platform
using 8mm wafers in the PSPI-6 XG variant has demonstrated ruptures or
abnormally high pressures during ballistic testing at a rate of 1.06%
of inflators tested, with all ruptures occurring in inflators field
aged 9.4 to 10.3 years.\204\ Even assuming this vehicle platform had a
higher peak vehicle temperature than that alleged for the GMT900
vehicles, analysis of these similar inflator variants contradicts GM's
claims that thinner propellant wafers render the GMT900 inflators less
susceptible to rupture and degradation.
---------------------------------------------------------------------------

    \201\ See 2020 Blomquist Report at paras. 201-05.
    \202\ Id.; information received by NHTSA pursuant to Standing
General Order 2015-01A.
    \203\ 2020 Blomquist Report at para. 204.
    \204\ Id. at para. 205.
---------------------------------------------------------------------------

    Given the severity of a rupture outcome, the observed propellant
degradation in the GMT900 inflators and inflator variants with similar
(if not identical) characteristics cannot be ignored; these test
results are consistent with the notion that the GMT900 inflators have
and will continue to suffer propellant degradation in a manner similar
to other non-desiccated PSAN inflators--and, in all events, that the
risk is not inconsequential to safety.
4. Predictive Modeling
    As noted above, it is the Agency's understanding that this Model
was informed by the GM Temperature Study and the Atlas Cabin
Temperature Study, as well as the GM Aging Study and the OATK Aging
Study.\205\ Accordingly, the concerns the Agency has with those inputs
(also described above) also adversely affect the reliability of the
Model as it applies to GM's arguments here. The implications of this
are even more pronounced when the number of trials in the underlying
simulation are too small to detect certain rupture rates: If the risk
of rupture is 1 in 100,000, then based on a Monte Carlo simulation with
32,000 trials, the OATK Model output would likely predict a zero risk
of rupture, clearly understating the potential risk. Even setting aside
concerns regarding the inputs, given the relative rarity of high
pressure and rupture events across the non-desiccated PSAN inflator
population, it is difficult to place much reliability on the OATK Model
outputs when evaluating the likelihood of a rupture of a YP or YD
inflator variant.\206\
---------------------------------------------------------------------------

    \205\ See also id. at paras. 250, 272.
    \206\ See id. at para. 252 (observing high-pressure and rupture
events in the Takata non-desiccated PSAN population ``are relatively
rare . . . for all vehicle platforms, with rupture rates for most
variants well under 1%. Modeling at sufficient fidelity to predict
low frequency events is challenging''). The Model's reliability for
the purpose of advancing GM's arguments here is further called into
question by its inability to produce similar probabilities for GM's
YP inflators and the non-GM DH/MG inflators, which are nearly
identical. See id.
---------------------------------------------------------------------------

    Additionally, the OATK Model outputs underestimate the risk for
consumers with YP or YD inflators exposed to the most extreme
conditions. The OATK Model selects 32,000 random scenarios that combine
different inputs of density and pressure; some of the 32,000 selected
scenarios will pose a higher risk (i.e., have a combination of density
and pressure that is more rupture-prone) and some will pose a lower
risk (i.e., be less rupture-prone).\207\ As a result, the output will
tend to reflect the risk posed by an average inflator, thereby
underestimating the risk posed by inflators subjected to the most
extreme conditions. These shortcomings also reflect an underestimation
of how quickly an inflator degrades--undermining GM's claim that GMT900
inflators will not reach a ``threshold risk

level'' within 30 years of worst case environmental field exposure in
Miami.
---------------------------------------------------------------------------

    \207\ See GM's June 8, 2018 Presentation at 10-14.
---------------------------------------------------------------------------

5. Risk Assessments
    GM also presented statistical risk assessments from third parties
Cornerstone and Professor Barnett, and OATK, which attempted to
quantify the future risk of rupture for the GMT900 inflator variants,
as described above. NHTSA does not find GM's statistical analysis
persuasive, as there are multiple foundational concerns with GM's risk
estimates.
    First, GM's risk assessments depend upon the inputs and outputs
from the OATK Model, the OATK Aging Study, and GM's crash data
estimates, as well as information from the MEAF file.\208\ Given the
extent to which GM's various analyses and assessments inform one
another, it is critical that the studies that fall earlier in the chain
and the associated results and conclusions are sound. As described
above, GM has not demonstrated the reliability and persuasiveness of
those studies or the associated results and conclusions.
---------------------------------------------------------------------------

    \208\ See Third Petition at 15; GM's August 23, 2017
Presentation at 22, 24-30; GM's June 8, 2018 Presentation at 11-17,
24-26.
---------------------------------------------------------------------------

    Second, it is a basic principle of statistics that to demonstrate
an outcome with higher confidence, all other things being equal, larger
sample sizes are necessary.\209\ Given the low number of inflators
tested and utilized in the earlier studies \210\--particularly when
combined with the challenge posed by using models to predict low-
frequency events--it is difficult to have confidence in GM's risk
estimates, especially in the context of a decision on
inconsequentiality. Moreover, GM did not provide any margins of error
on their risk estimates--particularly important when evaluating the
risk of a catastrophic event like an inflator rupture.\211\
---------------------------------------------------------------------------

    \209\ See generally NIST/SEMATECH e-Handbook of Statistical
Methods at <IP_ADDRESS>, available at http://www.itl.nist.gov/div898/handbook (choosing a sampling plan with a given Operating
Characteristic (``OC'') Curve; id. at <IP_ADDRESS> (providing example
calculation of sample-size estimate for limiting error); id. at
<IP_ADDRESS> (Populations and Sampling).
    \210\ See generally supra.
    \211\ While GM's upper bounds on the lifetime risk could be
construed as a type of margin of error, it does not take into
account important sources of variation, such as the Monte Carlo
simulation.
---------------------------------------------------------------------------

    Third, GM's comparative risk assessments (comparing the rupture
rate of GMT900 inflators to those of other inflators through the OATK
Aging Study, Takata MEAF data, and GM's crash estimates) \212\ simply
assert that GMT900 inflators are safer than other inflators--not that
the defect is inconsequential.
---------------------------------------------------------------------------

    \212\ See GM's June 8, 2018 Presentation at 20-22.
---------------------------------------------------------------------------

    And fourth, even to the extent GM's per-deployment or lifetime risk
estimates inform the question of inconsequentiality, they do not
reflect the compounding risk that arises from having millions of
affected vehicles. The per-deployment risk is the risk that one
specific air bag will rupture; the fleet-level risk is the probability
that at least one air bag will rupture among the thousands of air bag
deployments expected to occur in the nearly 5.9 million affected GMT900
vehicles over the coming years. GM did not provide any risk assessments
that acknowledge the risk presented by the GMT900 inflator population
as a whole, even though the fleet-level risk would be much larger than
the per-deployment risk.
    NHTSA also has additional, specific concerns about GM's various
risk estimates. GM's comparative risk assessments--to the extent they
inform the question of inconsequentiality--are undercut by the
ballistic results showing elevated pressures discussed above. That a
rupture has not yet been observed does not mean that ruptures will
never occur--nor that the risk to safety is inconsequential--and
estimates that ignore evidence that GM's inflators are experiencing a
similar manner of degradation do not provide meaningful comparison.
    In addition, GM's comparative risk estimates pool the risk posed by
inflators across ages and/or Zones, even though the risk of rupture
varies greatly between Zones A, B, and C and as the inflators age.\213\
This pooling typically dilutes the risk that exists in the higher risk
Zone A by combining it with the lower risk Zones.\214\ Similarly,
pooling younger inflators with older inflators dilutes the estimated
risk of rupture for those older inflators, particularly as inflator age
plays a vital role in the underlying defect. GM's comparative
assessment of estimated field crash rupture rates also assumes both
that GM's crash deployment estimates are accurate and that passenger
air bag ruptures are reported (as such). As discussed above, these
assumptions are not supported.\215\
---------------------------------------------------------------------------

    \213\ See GM's June 8, 2018 Presentation at 21-22, 39.
    \214\ GM's July 2018 Response (Ex.A) did provide estimates
specific to Zone A; however, the response pooled the risk for the
two inflator variants (YD and YP).
    \215\ There were also significant inconsistencies between the
production numbers GM relied upon in arriving at these estimates and
comparative registration data. See GM's July 2018 Response at 6-8.
Additionally, GM's future deployment risk estimates assume that a
passenger will be present in 25% of future GMT900 crashes, which is
not consistent with National Automotive Sampling System General
Estimates System (NASS GES) estimates.
---------------------------------------------------------------------------

    Similarly concerning is that GM's per-deployment risk estimate of
zero percent for the GMT900 vehicles relies on the assumption that GM's
vehicles have a low vehicle cabin temperature,\216\ but data provided
by GM suggested that at least one GMT900 variant fell within a higher
temperature range during testing--undermining both its risk estimates
and GM's argument that all GMT900 vehicles have a lower cabin
temperature due to a unique vehicle environment.\217\ GM's ``lifetime
risk'' estimate similarly suffers from questionable temperature range
assumptions.\218\ Moreover, the YP inflators will deploy any time
sensors determine a crash of sufficient force is in progress--whether a
passenger is present or not.\219\ It is therefore not accurate to
assume that occupants would not be harmed by the rupture of a passenger
air bag when no passenger is present; indeed, occupants have suffered
injuries from Takata inflator ruptures that did not occur directly in
front of them.\220\ And just like the assessments comparing GMT900
inflator rupture rates to the OATK Aging Study and MEAF data, GM's
prediction of future rupture rates implies that because ruptures have
(reportedly) not yet occurred they are unlikely to occur in the future.
As this assumption is not accurate, these estimates are not persuasive
in supporting GM's position that the Takata PSAN defect in the GMT900
vehicles is inconsequential to safety.
---------------------------------------------------------------------------

    \216\ Id. Ex.C (providing, inter alia, temperature bands and
probability).
    \217\ See GM's August 23, 2017 Presentation 8 (reflecting
average peak and maximum peak temperatures in Michigan, Florida, and
Arizona).
    \218\ See GM's June 8, 2018 Presentation at 26 (utilizing an
average probability of failure for T1 and T2 as an upper bound).
    \219\ See id. at 36 (reflecting 25% passenger air bag activation
rate for YD, and 100% activation rate for YP in front deployment
level crashes).
    \220\ Information received by NHTSA pursuant to Standing General
Order 2015-01A.
---------------------------------------------------------------------------

6. Dealer Replacements as Risk Creation
    Finally, GM's claim that dealers conducting repairs for these
vehicles could ``create risk'' to consumers \221\ has no bearing on the
question of whether the defect is inconsequential to safety. Even if
the Agency were to consider any potential risk posed by potential
improper repair in analyzing the consequentiality of a rupturing
inflator, GM provided no information to corroborate or support this
broad,

speculative statement. GM can and does ensure quality recall repairs by
specifying technician qualifications and repair techniques for its
franchised dealer network.
---------------------------------------------------------------------------

    \221\ Third Petition at 17; see also Fourth Petition at 16; GM's
June 8, 2018 Presentation at 5.
---------------------------------------------------------------------------

V. Decision

    The relief sought here is extraordinary, and GM's Petition goes far
beyond the scope and complexity of any inconsequentiality petition that
the Agency has considered, let alone granted. This is with respect not
only to the volume of information and analyses bearing on the issue,
but also the nature of the defect and associated safety risk. Indeed,
the Petition concerning GMT900 inflators is quite distinct from the
previous petitions discussed above, for example, relating to defective
labels that may (or may not) mislead the user of the vehicle to create
an unsafe condition.\222\ Nor is the risk here comparable to a
deteriorating exterior component of vehicle that--even if an average
owner is unlikely to inspect the component--might (or might not) be
visibly discerned.\223\
---------------------------------------------------------------------------

    \222\ See Nat'l Coach Corp.; Denial of Petition for
Inconsequential [Defect], 47 FR 49517 (Nov. 1, 1982); Suzuki Motor
Co., Ltd.; Grant of Petition for Inconsequential Defect, 48 FR 27635
(June 16, 1983).
    \223\ See Final Determination & Order Regarding Safety Related
Defects in the 1971 Fiat Model 850 and the 1970-74 Fiat Model 124
Automobiles Imported and Distributed by Fiat Motors of N. Am., Inc.;
Ruling on Petition of Inconsequentiality, 45 FR 2134 (Jan. 10,
1980).
---------------------------------------------------------------------------

    Rather, the defect here poses an unsafe condition caused by the
degradation of an important component of a safety device that is
designed to protect vehicle occupants in crashes. Instead of protecting
occupants, this propellant degradation can lead to an uncontrolled
explosion of the inflator and propel sharp metal fragments toward
occupants in a manner that can cause serious injury, including
lacerations to the face, neck and chest, and even death.\224\ This
unsafe condition--hidden in an air bag module--is not discernible even
by a diligent vehicle owner, let alone an average owner.\225\
---------------------------------------------------------------------------

    \224\ Cf. Gen. Motors, LLC; Grant of Petition for Decision of
Inconsequential Noncompliance, 78 FR 35355-01, 2013 WL 2489784 (June
12, 2013) (finding noncompliance inconsequential where ``occupant
classification system will continue to operate as designed and will
enable or disable the air bag as intended'').
    \225\ See Final Determination & Order Regarding Safety Related
Defects in the 1971 Fiat Model 850 and the 1970-74 Fiat Model 124
Automobiles Imported and Distributed by Fiat Motors of N. Am., Inc.;
Ruling on Petition of Inconsequentiality, 45 FR 2134 (Jan. 10, 1980)
(rejecting argument there was adequate warning to vehicle owners of
underbody corrosion, as the average owner does not undertake an
inspection of the underbody of a vehicle, and interior corrosion of
the underbody may not be visible).
---------------------------------------------------------------------------

    Moreover, nineteen manufacturers (including GM for other
populations of their vehicles) have conducted similar recalls of other
non-desiccated PSAN inflators. NHTSA has been offered no persuasive
reason to think that without a recall, even if current owners are aware
of the defect and instant petition, subsequent owners of vehicles
equipped with GMT900 air bag inflators would be made aware of the
issue.\226\ This is not the type of defect for which notice alone
enables an owner to avoid the safety risk. A remedy is required.
---------------------------------------------------------------------------

    \226\ See Nat'l Coach Corp.; Denial of Petition for
Inconsequential [Defect], 47 FR 49517 (Nov. 1, 1982) (observing,
inter alia, that other manufacturers had conducted recalls for
similar issues in the past, and that, even if current owners were
aware of the issue, subsequent owners were unlikely to be aware
absent a recall).
---------------------------------------------------------------------------

    The threshold of evidence necessary to prove the inconsequentiality
of a defect such as this one--involving the potential performance
failure of safety-critical equipment--is very difficult to overcome. GM
bears a heavy burden, and the evidence and argument GM provides suffers
from numerous, significant deficiencies, as previously described in
detail.
    The ``unique'' inflator design differences and vehicle features to
which GM points are unpersuasive. The use of thinner wafers is not
unique to GMT900 inflators--other Takata inflator variants with 8mm
wafers have experienced ruptures and abnormally high pressures during
ballistic testing--and the results of the OATK Aging Study and testing
data obtained on field aged inflators, at most, show that GMT900
inflators age more slowly than the worst performing inflator variants.
Moreover, four GMT900 inflators have experienced abnormally high peak
pressures consistent with propellant degradation. Larger vent areas in
GMT900 inflators do not render those inflators more resistant to
rupture, as the vent area does not change to address steep internal
pressure increases that occur when a defective PSAN inflator abnormally
deploys. GM did not demonstrate that steel endcaps provide any
measurable advantage over other variants with respect to moisture
intrusion. GM did not provide data demonstrating a correlation between
lower peak temperatures and either solar absorbing glass or larger
cabin volume, or demonstrate that alleged internal vehicle temperatures
rendered the GMT900 inflators more resilient to rupture. And other
design differences to which GM points--tablets in a cup, the
incorporation of a ceramic cushion, and the incorporation of a bulkhead
disk with an anvil--were not discussed in detail in its Petition, and
in any event, either lack supporting data, or the data that GM did
provide does not demonstrate that the design difference results in a
reduced risk of rupture.
    GM's stress-strength interference analysis ignores other indicators