19 pharmaceuticals, including vaccines. Specifically, the 2021-2022
ICAO Technical Instructions except these devices from lithium battery
marking and documentation requirements when transported by aircraft.
Consequently, PHMSA proposes exceptions in this section of the HMR to
cover all modes of transportation for certain devices or equipment
containing hazardous materials that are in actual use or which are
intended for use during transport. However, the exceptions associated
with aircraft transportation are limited to marking and documentation
for lithium ion and lithium metal battery-powered devices or equipment
that accompany shipments of COVID-19 pharmaceuticals, including
vaccines. PHMSA requests comments on whether this exception for air
transport should be expanded to additional medical supplies not related
to COVID-19 (e.g., other vaccines or more generally medicines).
---------------------------------------------------------------------------

    \19\ ICAO, Addendum No.1 to the 2021-2022 of the ICAO Technical
Instructions for the Safe Transport of Dangerous Goods by Air (Dec.
31, 2020), https://www.icao.int/safety/DangerousGoods/AddendumCorrigendum%20to%20the%20Technical%20Instructions/Doc%209284-2021-2022.AddendumNo1.en.pdf.
    \20\ ICAO, Addendum No.2 to the 2021-2022 of the ICAO Technical
Instructions for the Safe Transport of Dangerous Goods by Air (Feb.
23, 2021),https://www.icao.int/safety/DangerousGoods/AddendumCorrigendum%20to%20the%20Technical%20Instructions/Doc%209284-2021-2022.AddendumNo2.en.pdf.
---------------------------------------------------------------------------

Section 173.27
    Section 173.27 provides the general requirements for transportation
by aircraft. PHMSA proposes a number of corrections and revisions as
follows: (1) Revise paragraph (c)(2) to clarify that all package types
containing ``UN3082, Environmentally hazardous substance, liquid,
n.o.s.'' are excepted from the pressure differential requirements and
not only limited quantities; (2) revise the paragraph (f) introductory
text to clarify the inner packaging quantity limits prescribed in Table
1 and Table 2 apply to combination packages and not only to excepted
quantity packages; (3) in paragraph (f)(3) Table 1 and Table 2 add
inner package limits for certain Class 9 HMT entries consistent with
the ICAO Technical Instructions; and (4) in Table 1 and Table 2 remove
the ``no limit'' quantity limits and add them to the paragraph (f)
introductory text for a clearer description of the requirement for
materials authorized to exceed 220 L or 200 kg in accordance with
columns (9A) and (9B) of the 172.101 table. The 2021-2022 edition of
the ICAO Technical Instructions contains editorial corrections to
exceptions for ``UN3082, Environmentally hazardous substance, liquid,
n.o.s.'' from differential pressure testing requirements in Packing
Instructions 964 and Y964 (limited quantity). When reviewing the
clarifying editorial correction \21\ to the ICAO exception, PHMSA found
that although the same update is not needed in the HMR, the
corresponding exceptions in Sec.  173.27 are not consistent with those
provided for in the latest version of Packing Instructions 964 and
Y964. PHMSA proposes revising Sec.  173.27 to correct this discrepancy
and align with the updated version of the ICAO Technical Instructions.
---------------------------------------------------------------------------

    \21\ Report of the ICAO Working Group 19 (paragraph 3.2.11)
(May, 2019), https://www.icao.int/safety/Dangerousfxsp0;Goods/WG19/
DGPWG.19.fxsp0;WP.030.en.pdf.
---------------------------------------------------------------------------

    In a previous final rule, HM-215K,\22\ PHMSA revised Sec.  173.27
to align with the amendments made to the 2011-2012 edition of the ICAO
Technical Instructions. That earlier edition of the ICAO Technical
Instructions had included exceptions applicable to UN3082 from the
pressure differential requirements in Packing Instructions 964 and Y964
for fully regulated and limited quantity packages. The exceptions were
added because UN3082 materials assigned to Class 9 do not meet the
criteria for classification as any other hazard class or division and
are classified as hazardous materials solely because of their risk to
the environment (i.e., they are not capable of posing a risk to health,
safety, or property when transported by air). When this exception was
added in the HM-215K rulemaking, the text was placed in paragraph
(f)(2)(vii), thereby inadvertently narrowing the exception to limited
quantity materials. In the 2011-2012 edition of the ICAO Technical
Instructions that the HM-215K rulemaking intended to align with, the
exception from the pressure differential requirements applied to both
combination packagings in PI 964 and limited quantity packagings in PI
Y964. Therefore, PHMSA proposes to amend paragraph (c)(2) to except
shipments of ``UN3082, Environmentally hazardous substance, liquid,
n.o.s.'' from the pressure differential packaging requirements
applicable for transportation by aircraft. This proposed change would
align the pressure differential exceptions for UN3082 material with
those found in the ICAO Technical Instructions and excepts these
shipments, in all authorized packaging types, from the pressure
differential requirements in paragraph (c)(2).
---------------------------------------------------------------------------

    \22\ 76 FR 3308 (Jan. 19, 2011).
---------------------------------------------------------------------------

    Further, PHMSA proposes to amend paragraph (f), which specifies
requirements for combination packagings intended for transportation
aboard an aircraft. A combination packaging, for transport purposes,
consists of one or more inner packagings secured in a non-bulk outer
packaging. Paragraph (f)(3) contains Table 1 and Table 2 indicating the
maximum net capacity allowed for the inner packagings of the
combination packaging on passenger-carrying and cargo aircraft,
respectively. PHMSA proposes to revise paragraph (f) by moving the
references to Table 1 and Table 2 from paragraph (f)(1), applicable to
excepted quantities, to the paragraph (f) introductory text. The intent
of this revision is to clarify that the inner packaging limits
specified in paragraph (f)(3) Table 1 and Table 2 apply to all
combination packages used to transport hazardous material by aircraft
and not just to excepted packages (i.e., packages for which exceptions
from certain provisions are provided in the HMR). As it currently
reads, the instruction for all combination packagings is imbedded in
the paragraph (f)(1), which outlines provisions for excepted packages,
thus making it appear that Tables 1 and 2 apply only to excepted
packages. Correcting the reference in paragraph (f) would provide
regulatory clarity by properly aligning packaging limits in

the HMR with the ICAO Technical Instructions.
    Additionally, the first column of Tables 1 and 2 provides the
maximum net quantity per package from Column (9A) of the HMT. PHMSA
proposes to replace the rows in Tables 1 and 2 noting that there are no
maximum net capacity limits for quantities greater than 220 L for
liquids and greater than 200 kg for solids with an instruction in the
revised paragraph (f) introductory text conveying the same information.
    Finally, PHMSA discovered that for certain Class 9 (miscellaneous
hazardous) materials, the authorized inner packaging limit in the ICAO
Technical Instructions is greater than the limit currently allowed in
Tables 1 and 2 at Sec.  173.27(f)(3). Therefore, PHMSA proposes to
revise paragraph (f)(3), Table 1 and Table 2 to address this
inconsistency with the ICAO Technical Instructions. Specifically, PHMSA
proposes to revise, for consistency with the inner packaging limits
provided in Packing Instructions 956, 958, and 964 of the ICAO
Technical Instructions, inner packaging net capacity limits for the
following Class 9 materials:

 UN1841 Acetaldehyde ammonia
 UN1931 Zinc dithionite or Zinc hydrosulphite
 UN1941 Dibromodifluoromethane
 UN1990 Benzaldehyde
 UN2071 Ammonium nitrate fertilizers
 UN2216 Fish meal, stabilized or Fish scrap, stabilized
 UN2315 Polychlorinated biphenyls, liquid
 UN2590 Asbestos, chrysotile
 UN2969 Castor beans or Castor flake or Castor meal or Castor
pomace
 UN3077 Environmentally hazardous substance, solid, n.o.s.
 UN3082 Environmentally hazardous substance, liquid, n.o.s.
 UN3151 Polyhalogenated biphenyls, liquid or Polyhalogenated
terphenyls, liquid or Halogenated monomethyldiphenylmethanes, liquid
 UN3152 Polyhalogenated biphenyls, solid or Polyhalogenated
terphenyls, solid or Halogenated monomethyldiphenylmethanes, solid
 UN3334 Aviation regulated liquid, n.o.s.
 UN3335 Aviation regulated solid, n.o.s.
 UN3432 Polychlorinated biphenyls, solid
    These materials have a history of safe transport under less
restrictive inner packaging limits in accordance with the ICAO
Technical Instructions. The proposed revisions would offer shippers
greater flexibility in packaging options to transport these materials
without a degradation of safety.
Section 173.59
    Section 173.59 provides informational descriptions of terms for
explosives. PHMSA proposes to amend the description of the term
``detonators'' to include a reference to electronic programmable
detonators. Additionally, PHMSA proposes to add a separate term and
description for ``Detonators, electronic programmable for blasting.''
These changes correspond to the proposed addition of the UN0511,
UN0512, and UN0513 (Detonators, electronic programmable for blasting)
to the HMT. PHMSA intends to distinguish between ``electronic
detonators'' and ``electric detonators,'' as each has different design
characteristics, by adding these new entries in the HMT and the
editorial amendments in Sec.  173.59. PHMSA expects this additional
precision in shipping descriptions will provide a safety benefit. See
Sec.  172.101 of the Section-By-Section Review for additional
discussion on electric and electronic detonators.
Section 173.115
    Section 173.115 outlines classification criteria for Class 2 (gas)
materials. PHMSA proposes to update the version of ISO 10156:2010,
``Gases and gas mixtures--Determination of fire potential and oxidizing
ability for the selection of cylinder valve outlets,'' that is
incorporated by reference in paragraph (k), which specifies how the
oxidizing ability of a Division 2.2 (non-flammable) gas should be
calculated. Currently the HMR incorporates by reference the 2010
edition of this ISO standard and its associated technical corrigendum
in Sec.  171.7. As part of ISO's regular periodic review of each
standard, ISO standard 10156:2010 was reviewed and updated and a new
revised ISO 10156:2017 was published September 2017. The 2017 edition
supersedes and replaces ISO 10156:2010, which had been technically
revised through ISO 10156:2010/Cor 1:2010. PHMSA now proposes to update
the incorporation by reference of ISO 10156, to the 2017 edition. The
updated document includes technical revisions pertaining to the
flammability of gases and gas mixtures in air as well as a new
calculation method for determining the lower flammability limit of gas
mixtures. PHMSA reviewed the calculation method and agrees that it will
assist shippers in properly classifying a Division 2.2 gas, without
introducing any adverse safety risks. Therefore, PHMSA proposes to
incorporate by reference ISO 10156:2017 in Sec.  173.115(k).
Section 173.134
    Section 173.134 provides classification criteria and exceptions for
Division 6.2 infectious substances. PHMSA proposes to revise paragraph
(a) to include references to ``UN3549, Medical Waste, Category A,
Affecting Humans, solid or Medical Waste, Category A, Affecting Animals
only, solid.'' Specifically, paragraphs (a)(1), (a)(1)(i), and (a)(5)
would be revised by including UN3549 among the list of UN numbers to
use for description of an infectious substance. These proposed changes
are consistent with the proposed addition of this new hazardous
materials description to the HMT.
    Additionally, PHMSA proposes to remove the term rickettsiae from
the list of types of microorganisms in paragraph (a)(1). Rickettsiae
are a specific group of bacteria, and this specific type of bacteria is
redundant because bacteria are already listed as a type of potential
pathogenic microorganism.
Section 173.137
    Section 173.137 prescribes the requirements for assigning a PG to
Class 8 (corrosive) materials. The HMR requires offerors to classify
Class 8 material and assign a PG based on tests conducted in accordance
with the OECD Guidelines for the Testing of Chemicals. One of the tests
currently authorized in the HMR is the 2015 OECD Guideline for the
Testing of Chemicals ``Test No. 431: In vitro skin corrosion:
reconstructed human epidermis (RHE) test method'' which may be used to
determine that a material is not corrosive to human skin. PHMSA
proposes to incorporate by reference the 2016 version of OECD
Guidelines for the Testing of Chemicals ``Test No. 431: In vitro skin
corrosion: reconstructed human epidermis (RHE) test method.'' This
document was updated to introduce sub-categorization for skin corrosion
and adopted by the OECD in 2013 and further revised in 2014, 2015, and
2016, as Guidelines for the Testing of Chemicals ``Test No. 431: In
vitro skin corrosion: reconstructed human epidermis (RHE) test
method.'' According to the OECD, this updated test method permits
subcategorization of corrosive chemicals into three categories: sub-
category 1A and sub-category 1B/C, which correspond to PG I, PG II, and
PG III, respectively. However, prior to the 2016 edition of the OECD
Guidelines, the ability to clearly distinguish between PG II and

PG III had previously never been formally evaluated or validated due to
the lack of high quality reference in vivo data against which to
benchmark the in vitro results.
    Changes to the UN Model Regulations were made as a result of the
additional level of sub-categorization and differentiation that is
possible using this updated test method. Accordingly, PHMSA also
proposes to allow corrosive materials that are tested using OECD
Guidelines for the Testing of Chemicals Test No. 431 to be assigned to
PG II without further in vivo testing if the test method does not
clearly distinguish between PG II or PG III. Since the packing group
assignment indicates the required level of packaging according to the
degree of danger presented by hazardous materials, this would relegate
corrosive material that cannot be clearly distinguished between a
medium danger PG II and a low danger PG III to be subject to the more
conservative packaging requirement associated with PG II material
unless additional testing is conducted. PHMSA anticipates that the use
of the 2016 version of the OECD Guidelines for the Testing of Chemicals
Test No. 431 will benefit shippers of potential corrosives by
clarifying corrosivity determinations or exclusions, and eliminating
excessive testing to distinguish between PG II and PG III.
    The proposed regulatory text references OECD Guidelines for the
Testing of Chemicals Test No. 404, 430, and 435, which are already
approved for incorporation by reference in this section, and no change
is proposed for these standards.
Section 173.172
    Section 173.172 specifies the eligibility conditions for exception
from packaging requirements for certain fuel tanks used on aircraft
hydraulic power units. PHMSA proposes editorial changes to these
provisions to clarify packaging limits for the fuel tanks that power
hydraulic power units. The fuel tanks addressed in this section are
comprised of a primary containment for the fuel in the hydraulic power
unit. The primary containment must consist of a welded aluminum bladder
as well as an outer vessel, which is packed in non-combustible
cushioning material in a strong, tightly-closed metal outer packaging.
Currently paragraphs (a) and (b) of this section state that the
``Maximum quantity of fuel per unit and package is 42 L (11 gallons).''
PHMSA proposes to replace the word ``unit'' in this sentence in
paragraphs (a) and (b) with the word ``primary containment'' for
consistency with the second sentence of each paragraph which states
that the ``primary containment of the fuel within this vessel must
consist of a welded aluminum bladder having a maximum internal volume
of 46 L (12 gallons).'' These editorial revisions to clarify that the
maximum quantity of fuel authorized applies to both the fuel within the
vessel and completed package (primary containment) rather than the
hydraulic power unit itself. This change would align the language for
this packaging exception in the HMR with the language that was
similarly amended in the 2021-2022 ICAO Technical Instructions and the
21st revised edition of the UN Model Regulations. PHMSA does not expect
this change to adversely affect safety benefits.
Section 173.181
    Section 173.181 prescribes packaging requirements for liquid
pyrophoric materials. Specifically, Sec.  173.181 provides the
requirements on closures for metal or glass receptacles when used as
inner packagings (i.e., receptacles) in combination packagings. The UN
Model Regulations contains Packing Instruction P404 which includes
provisions for resealing inner receptacles with threaded closures.
Currently, Sec.  173.181 does not include provisions for resealing of
inner receptacles with threaded closure. The safety concern when
resealing inner receptacles that contain liquid pyrophoric materials is
that small amounts of residue may adhere to the threads and present a
hazard upon closing of the inner packaging and that friction generated
from screwing the cap back onto the receptacle may cause the residue to
react critically (e.g., self-heating or spontaneous combustion). Based
on this concern, the UN Model Regulations now permit closures of inner
receptacles to be either threaded or physically held in place by any
means capable of preventing back-off or loosening of the closure under
conditions normally incident to transportation (e.g., vibration during
transport). PHMSA is also concerned about this potential hazard and
proposes to authorize an alternative method of closure to prevent this
potential hazard. Therefore, PHMSA proposes to revise the requirements
of Sec.  173.181 for closures of inner packagings for liquid pyrophoric
materials to specify that they may have closures that are physically
held in place by any means capable of preventing back-off or loosening
during transportation.
Section 173.185
    Section 173.185 prescribes requirements for transportation of
lithium cells and batteries. Paragraph (c) prescribes requirements for
smaller cells or batteries and paragraph (c)(3) specifies hazard
communication requirements including the use of the lithium battery
mark. PHMSA proposes to revise the minimum size of the lithium battery
mark from 120 millimeters (mm) wide by 110 mm high to 100 mm by 100 mm.
This reduction in size requirements for this mark would be consistent
with the existing minimum size requirements for the limited quantity
and excepted quantity marks in the HMR (see Sec. Sec.  172.315 &
173.4a) and does not diminish the ability to read or recognize the
marking. The reference to the shape of the mark would be amended to
include ``square'' to account for the new minimum dimensions while also
maintaining the existing shape of a ``rectangle'' to continue
authorized use of the lithium battery mark with 120 mm by 110 mm
dimensions. In addition, the minimum size of the lithium battery mark
for packages too small to display the revised 100 mm by 100 mm
dimensions, would be revised from 105 mm wide by 74 mm high to 100 mm
wide by 70 mm high. Additionally, an informal working paper \23\
submitted to the 54th Session of the UNSCOE noted that due to the large
volume of lithium batteries shipped in small packages, the reduction in
the size of the mark could reduce the quantity of packagings produced
and consequently the quantity of empty packagings sent for disposal or
recycling. This proposed minimum size would not invalidate use of
larger marks meeting the currently authorized minimum size
requirements.
---------------------------------------------------------------------------

    \23\ Rechargeable Battery Association (PRBA) & the Advanced
Rechargeable & Lithium Batteries Association (RECHARGE), Proposal on
the Dimensions of the Lithium Battery Mark Submitted to the UN
Subcommittee of Experts on the Transport of Dangerous Goods at the
54th Session (Dec. 3, 2018), https://www.unece.org/fileadmin/DAM/trans/doc/2018/dgac10c3/UN-SCETDG-54-INF55.e.pdf.
---------------------------------------------------------------------------

Section 173.187
    Section 173.187 prescribes packaging requirements and other
provisions for ``pyrophoric solids, metals, or alloys, n.o.s.'' The
21st revised edition of the UN Model Regulations includes an amendment
to Packing Instruction P404 to address concerns with threaded closures
when resealing inner receptacles after partial removal of product. The
amendment addresses small amounts of residue of pyrophoric materials
that may adhere to the threads and present a hazard upon closing of an

inner receptacle. As with liquid pyrophoric materials, discussed above,
there is concern that friction generated from screwing the cap back
onto the inner receptacle may cause the residue to react critically
(e.g., self-heating or spontaneous combustion). Based on this concern,
the UN Model Regulations now allow closures of inner receptacles to be
either threaded or physically held in place by a means capable of
preventing back-off or loosening of the closure under conditions
normally incident to transportation (e.g., impact or vibration during
transport).
    After reviewing this issue, PHMSA is also concerned about this
potential hazard and proposes to amend Sec.  173.187 to authorize an
alternate method of closure to prevent this potential hazard.
Specifically, PHMSA proposes to revise the requirements for closures of
inner receptacles for solid pyrophoric materials to specify that they
may have threaded closures or other closures that are physically held
in place by a means capable of preventing back-off or loosening.
Section 173.199
    Section 173.199 prescribes the packaging requirements for Division
6.2, Category B infectious substances. Consistent with the ICAO
Technical Instructions, PHMSA proposes to revise paragraph (a)(5) to
require that for air transport the entire UN3373 mark must appear on
one side of the package. PHMSA expects that placing marks on a single
side of a package will provide increased visibility of hazard
communication on the smaller package types that are frequently used in
air transport. These measures would also reduce ambiguity for air
operator employees conducting acceptance checks as to whether the
package appropriately indicates the hazards without having to make a
subjective determination. Regarding the Category B infectious substance
mark, the proposal would help ensure that any packages containing
infectious substances, including COVID-19 materials, have appropriate
visibility and thus, ensure the safe transport of such materials. For
details on the rationale for this proposed requirement, see the
discussion of Sec.  172.406 in the Section-By-Section Review.
Section 173.218
    Section 173.218 contains packaging and product stabilization
requirements for transporting stabilized fish meal or fish scrap
(UN2216) as a Class 9 material. Currently, the provisions of this
section are limited to shipments by vessel; however, PHMSA proposes to
revise this provision to authorize the transport of this material by
air. This change responds to changes in the fish meal or fish scrap
market which has experienced an increased demand for more timely
shipments of samples of this item for evaluation by potential
purchasers. Adding provisions to permit shipment by air, rather than
limiting to shipment by vessel, would relieve frustration in the market
for fish meal or fish scrap by allowing shipments of small amounts of
this material to be expedited by air. This change is consistent with
amendments adopted in the 2021-2022 version of the ICAO Technical
Instructions, which have been revised to allow the transport by air of
non-bulk packages of fish meal or fish scrap, subject to quantity
limitations and stabilization requirements.
    As proposed, UN2216 material would be permitted on passenger
aircraft and cargo aircraft in amounts up to 100 kg and 200 kg,
respectively, and in UN performance packaging that aligns with the ICAO
Technical Instructions. Additionally, to ensure the safe transport of
this material by air, PHMSA proposes adding stabilization requirements
similar to those that are in place for shipments by vessel. PHMSA
proposes fish meal or fish scrap transported by air must have been
stabilized at production, and within the twelve months prior to
transportation. Given the safeguard provided by stabilization of this
material prior to transportation, as well as the proposed packaging and
quantity restrictions, PHMSA expects that there will be no degradation
of transportation safety in authorizing air transportation.
    In addition to adding these stabilization requirements for air
transportation, PHMSA proposes amending the stabilization requirements
that are currently in place for vessel shipments. The HMR currently
requires shipments of fish meal or fish scrap by vessel to contain at
least 50 parts per million (ppm) (mg/kg) of ethoxyquin, 100 ppm (mg/kg)
of butylated hydroxytoluene (BHT) or 250 ppm (mg/kg) of tocopherol
based antioxidant at the time of shipment for bulk shipments when
transported in freight containers. PHMSA proposes extending these
stabilization requirements to all vessel shipments, as required by the
IMDG Code. While the change in language would make the stabilization
requirement more widely applicable, PHMSA expects that the impact on
the regulated community will be minimal as fishmeal and fish scrap
shipments offered for transport (in non-bulk and bulk) are already
typically treated with quantities of stabilizer (antioxidants) well
above the minimum amounts currently shown in section Sec.  173.218 as
common industry practice.
Section 173.221
    Section 173.221 prescribes transportation requirements and
exceptions therefrom for ``UN2211, Polymeric beads expandable'' and
``UN3314, Plastic molding compound,'' which are both Class 9
(miscellaneous) materials. Historically, transportation of these
materials has been limited to single packagings under both the HMR and
in Packing Instruction 957 of the ICAO Technical Instructions. However,
these limitations are inconsistent with the UN Model Regulations and
the general provisions of the ICAO Technical Instructions, which permit
combination packagings when single packagings are authorized. These
packagings are constructed with inner packagings made of glass,
plastic, metal, paper, or fiber and with outer packagings utilizing
drums, boxes, and jerricans made of various materials. This conflict in
permitted packagings has been corrected in the most recent edition of
the ICAO Technical Instructions.
    PHMSA finds that allowing combination packaging for these Class 9,
low hazard materials is consistent with general packaging
authorizations throughout the HMR. In general, combination packaging is
allowed for materials that are more hazardous as long as the minimum
packaging performance requirements are achieved. Single packaging and
combination packaging are subject to the same performance standards,
meaning an equivalent level of safety is achieved. Therefore, PHMSA
proposes conforming changes to Sec.  173.221 to allow the use of
combination packagings (i.e., packagings that use a combination of
inner and outer packagings for containment) for these materials. This
change would provide packaging selection flexibility as well as
consistency with UN Model Regulations and revised ICAO Technical
Instructions without any impact on safe transport of these materials.
Section 173.222
    Section 173.222 specifies the non-bulk packaging requirements for
``UN3363, Dangerous goods in machinery or apparatus.'' As discussed in
connection to proposed changes to Sec.  172.101, PHMSA proposes to
modify the proper shipping name associated with UN3363 to include
``dangerous goods in articles,'' in addition to ``dangerous goods in
machinery or apparatus.'' In the HM-215O final rule,

PHMSA added new entries for articles containing hazardous materials
that are not otherwise specified by name in the HMT (e.g., ``UN3547,
Articles containing corrosive substance, n.o.s.''). These new entries
addressed transportation scenarios where various hazardous materials or
residues are present in articles above the quantities currently
authorized for machinery or apparatus transported as ``UN3363,
Dangerous goods in machinery or Dangerous goods in apparatus.'' In
addition to adding these new entries to the HMT, PHMSA added packaging
provisions in Sec.  173.232, as well as a definition for articles. The
definition states that ``article means machinery, apparatus, or other
devices containing one or more hazardous materials (or residues
thereof) that are an integral element of the article, necessary for its
functioning, and that cannot be removed for the purpose of transport.''
This addition created regulatory discrepancies between articles that
cannot be defined as machinery or apparatus but also do not qualify as
``Articles containing hazardous materials, n.o.s.'' even as there is no
safety basis to exclude such articles from the scope of Sec.  173.222
provisions. Therefore, PHMSA proposes to revise the provisions in Sec.
173.222 to reflect the addition of dangerous goods in articles to the
current HMT entry for ``UN3363, Dangerous Goods in Machinery or
Dangerous Goods in Apparatus'' as discussed in connection with the
proposed changes to Sec.  172.101 above. These proposed changes are
intended to provide flexibility in the choice of the most appropriate
modifier to be selected as a proper shipping name (e.g., article,
machinery, or apparatus). This flexibility in selecting the most
appropriate description of the hazardous material would help ensure
appropriate packaging selection and hazard communication, thus
enhancing safety.
Section 173.225
    Section 173.225 prescribes packaging requirements and other
provisions for organic peroxides. As a result of new peroxide
formulations becoming commercially available, the 21st revised edition
of the UN Model Regulations includes updates to the list of identified
organic peroxides and new packing instructions for these materials. To
maintain consistency with the UN Model Regulations, PHMSA proposes to
update the Organic Peroxide Table in Sec.  173.225(c) to revise the
entry ``Di-(4-tert-butylcyclohexyl) peroxydicarbonate [as a paste],''
by (1) changing the classification of the material as ``UN3116, Organic
peroxide type D, solid, temperature controlled'' to ``UN3118, Organic
peroxide type E, solid, temperature controlled''; and (2) changing the
packing method from OP7 to OP8.
    An organic peroxide Type D is an organic peroxide that: (1)
Detonates only partially, but does not deflagrate rapidly and is not
affected by heat when confined; (2) does not detonate, deflagrates
slowly, and shows no violent effect if heated when confined; or (3)
does not detonate or deflagrate, and shows a medium effect when heated
under confinement. An organic peroxide Type E is an organic peroxide
which neither detonates nor deflagrates and shows low or no effect when
heated under confinement. Di-(4-tert-butylcyclohexyl) peroxydicarbonate
was identified as a Type E organic peroxide based on evaluation of new
test data within the classification scheme for self-reactives and
organic peroxide in Figure 20.1 of the UN Model Regulations. Finally,
PHMSA proposes to revise the packing method from OP7 to OP8 consistent
with the revised classification of Di-(4-tert-butylcyclohexyl)
peroxydicarbonate to a lesser hazard Type E organic peroxide. The
packaging method indicates the largest size authorized for packaging of
a particular organic peroxide. Specifically, for Di-(4-tert-
butylcyclohexyl) peroxydicarbonate, assignment of OP8 would allow up to
400 kg for solids and combination packagings, and up to 225 L for
liquids. See Section 173.225 Section-by-Section Review for further
detail of packing methods for organic peroxides.
    PHMSA also proposes to revise the Organic Peroxide IBC Table in
paragraph (e) to maintain alignment with the 21st revised edition of UN
Model Regulations by adding new entries for ``tert-Amyl peroxypivalate,
not more than 42% as a stable dispersion in water'' and ``tert-Butyl
peroxypivalate, not more than 42% in a diluent type A'' and identifying
it as ``UN3119, Organic peroxide type F, liquid, temperature
controlled.'' PHMSA expects that adding provisions for the transport of
these newly available peroxide formulations will allow better oversight
for safe and consistent shipment of these hazardous materials.
Section 173.301B
    Section 173.301b outlines additional general requirements when
shipping gases in UN pressure receptacles (e.g., cylinders). Paragraph
(a)(2) of this section requires that the gases or gas mixtures be
compatible with the UN pressure receptacle and valve materials
prescribed for metallic materials in ISO 11114-1:2012(E), Gas
cylinders--Compatibility of cylinder and valve materials with gas
contents--Part 1: Metallic materials. This document provides
compatibility requirements for the selection of combinations of
metallic cylinder and valve materials for use with gas or gas mixtures.
In the interest of providing uniformity with regard to reference
standards used domestically and internationally, PHMSA proposes to
revise the compatibility requirements to include a reference to the
2017 amendment (ISO 11114-1:2012/Amd 2017(E)), which ISO published as a
supplement to ISO 11114-1:2012(E). This supplement provides enhanced
instructions on the permissible concentrations of certain gases to
ensure safe transport of a wider variety of gases in newly developed
types of metallic cylinders and valves.
    Second, PHMSA proposes to revise paragraph (c)(1), which specifies
valve requirements for pressure receptacles. Currently in the HMR,
paragraph (c)(1) requires valves for pressure receptacles (excluding
quick release cylinder valves, which must conform to the requirements
in ISO 17871:2015(E)) to conform to various editions of ISO 10297,
``Gas cylinders--Cylinder valves--Specification and type testing'',
including the 1999, 2006 and 2014 editions. ISO 10297:2014 specifies
design, type testing, and marking requirements for certain cylinder
valves intended to be fitted to refillable transportable gas cylinders
which convey compressed, liquefied or dissolved gases. PHMSA proposes
to modify the valve requirements in this paragraph such that when the
use of a valve is prescribed, the valve must conform to the
requirements of ISO 10297:2014 as well as the supplemental amendment,
ISO 10297:2014/Amd 1:2017. ISO 10297:2014/Amd 1:2017 corrects errors in
ISO 10297:2014 and also includes modifications for valves for tubes and
pressure drums. For consistency with the UN Model Regulations, PHMSA
also proposes to add a sunset date of December 31, 2022, for the
authorization of the use of ISO 10297:2014 when not used in conjunction
with the supplemental 2017 amendment. PHMSA has reviewed this
supplemental amendment as part of its regular participation in the
review of amendments proposed for the UN Model Regulations and does not
expect any degradation of safety standards in association with the use
of these two documents.
    Lastly, paragraph (c)(2) of this section outlines certain
requirements for valves

on UN pressure receptacles. Specifically, by following one of the
listed methods or standards in this paragraph, valves are required to
be protected from damage that could cause inadvertent release of their
contents. PHMSA proposes to introduce an additional option by allowing
the use of valves designed and constructed in accordance with Annex A
of ISO 17879:2017 for UN pressure receptacles with self-closing valves
with inherent protection (except those in acetylene service). Annex A
of ISO 17870:2017 is a new standard which establishes design, type
testing, marking, and manufacturing tests and examination requirements
for self-closing valves fitted to refillable transportable gas
cylinders conveying compressed, liquefied, or dissolved gases (other
than acetylene). PHMSA has determined that incorporating ISO 17879
fulfills the need for a standard that governs self-closing valves on
cylinders, which are typically used in the calibration, beverage, and
medical gas industries and mirrors requirements for impact testing and
burst testing specified in ISO 10297. PHMSA has experience with
permitting the use of valves constructed to ISO 17879 through special
permit,\24\ which has occurred without incident since 2019.
Incorporating this ISO standard would eliminate the need and associated
burden for manufacturers to request a special permit to use the valves
as they become more widely transported as a result of their
authorization by other competent authorities.
---------------------------------------------------------------------------

    \24\ See, e.g., Special Permit 20876 (Apr. 21, 2021), https://cms7.phmsa.dot.gov/approvals-and-permits/hazmat/file-serve/authorization/2019045387_SP20876.pdf/2019045387/SP20876.
---------------------------------------------------------------------------

    The proposed regulatory text references the following standards
that are already approved for incorporation by reference in this
section and no change is proposed for these standards: ISO 11114-
1:2012(E); ISO 11114-2:2013; ISO 10297:2014; ISO 17871:2015; ISO
11117:2008 and Technical Corrigendum 1; ISO 11117:1998; ISO 16111:2008.
Section 173.304B
    Section 173.304b contains requirements for shipment of liquefied
compressed gases in UN pressure receptacles. In this section, paragraph
(b) describes the filling limits for UN pressure receptacles expressed
in terms of ``filling ratio,'' or the ratio of the mass of gas in the
cylinder compared to the water capacity of the cylinder. Paragraph
(b)(2) of this section provides the maximum allowable filling limits
for low pressure liquefied gases. As currently provided in paragraph
(b) of 173.304b, the term ``filling factor'' is currently used to
describe the filling limit in terms of the maximum mass of contents in
kg of the gas per liter of water capacity, which is intended to have
the same meaning as the ``filling ratio.'' To increase clarity of the
HMR, PHMSA proposes to revise paragraph (b)(2) by deleting the term
``filling factor'' and only using the performance standard of ``maximum
mass of contents per liter of water capacity'' so that this is not
misunderstood as being different from the defined term ``filling
ratio.'' This change is consistent with the same editorial correction
made is the 21st revised edition of the UN Model Regulations. The term
``filling factor'' is used in the context of the UN Model Regulations
and could be misunderstood as being different from the defined term
``filling ratio.'' PHMSA expects that clarifying the language
pertaining to the filling ratio will provide a safety benefit by
eliminating confusion about the definition of the term ``filing
factor'' or ``filing ratio.''
Section 173.306
    Section 173.306 provides exceptions from HMR requirements for
transportation of limited quantities of compressed gases. Paragraph (f)
of this section provides exceptions for the transportation of
accumulators, which are transported under ``UN3164, Articles,
pressurized pneumatic or hydraulic.'' Accumulators are devices in which
a fluid is kept under pressure as a means of storing energy. PHMSA
proposes to revise paragraphs (f)(2) and (f)(3) to allow robust
accumulators to be transported unpackaged, in crates, or in overpacks
that provide equivalent protection to the hazardous material being
transported. The term robust is used to describe articles that are
strong enough to withstand the shocks and loadings normally encountered
during transport, including trans-shipment between cargo transport
units and between cargo transport units and warehouses, as well as any
removal from a pallet for subsequent manual or mechanical handling.
PHMSA expects that the proposed amendments will increase flexibility
for shippers and harmonize with revisions to the UN Model Regulations
which limits the packaging required for ``UN3164, Articles, pressurized
pneumatic or hydraulic'' when afforded equivalent protection by the
article being transported.
    Additionally, PHMSA proposes to add a new paragraph (n) to include
provisions for the transport of ``UN2037, Receptacles, small,
containing gas or gas cartridges'' for recycling or disposal. These
proposed provisions include packaging requirements, conditions for
exception, and maximum gross weight limits, applicable to small
receptacles or cartridges containing gas not exceeding 1.0 L (0.3
gallons) capacity. PHMSA expects that codifying these provisions will
create a regulatory framework for transporting these materials for
recycling or disposal and reduce the administrative burden that would
otherwise apply to fully regulated gas receptacles. Further, reducing
this administrative burden may lead to other environmental benefits by
facilitating shipments destined for recycling or disposal. PHMSA
solicits comments on the need to expand these provisions to other types
of authorized packagings mentioned in this section.
Section 173.335
    Section 173.335 specifies packaging requirements for hazardous
materials transported as chemicals under pressure (e.g., ``UN3500,
Chemical under pressure, n.o.s.''). Chemicals under pressure are
regulated as gases but differ in that they are liquids, pastes, or
powders, and pressurized with a propellant that meets the definition of
a gas in Sec.  173.115. Materials transported under UN3500 may include
those that are widely used in fire suppression systems and other items
used for fire control.
    PHMSA proposes to provide an extended periodic inspection period
for cylinders containing fire extinguishing agents transported under
UN3500. This amendment would be consistent with a new special packing
provision, PP97, added in the 21st revised edition of the UN Model
Regulations to provide a test period of 10 years for tubes (cylinders)
that have a capacity of 450 L or less and that are filled with fire
extinguishing agents. The intent of this change was to resolve the
discrepancy in inspection periods between (1) gas-filled cylinders
intended for installation in fire suppression systems and (2) cylinders
used for the same purpose, but which contain a fire extinguishing agent
(e.g., a liquid) in combination with a gas used as a propellant. Gases
transported under ``UN1956, compressed gas n.o.s.'' have a maximum test
period for periodic inspection of 10 years, whereas the maximum test
period for UN3500, chemical under pressure, n.o.s.'' is only five
years. However, the updated UN Model Regulations extended the
inspection period for cylinders containing fire extinguishing agents
transported under UN3500 because they are typically (1) inert chemicals
with no

subsidiary risks and (2) they are typically filled at lower pressures
than cylinders containing UN1956 materials. Additionally, these fire
extinguishing materials and devices are maintained and stored in a
manner that minimizes the degradation of the cylinder (e.g., in
protected indoor environments).
    A recent PHMSA rulemaking, HM-234,\25\ broadened the scope of
cylinders eligible to be classified as ``UN1044, fire extinguishers''
and the intent was to permit cylinders charged with fire extinguishing
agents intended for use in fire suppression systems to be described and
transported under ``UN1044, fire extinguishers.'' However, cylinders
charged solely with a compressed gas or liquefied gas and used in a
fire suppression system solely to expel a separately stored
extinguishing agent are not eligible for transportation under UN1044.
Furthermore, with respect to the UN Model Regulations, cylinders
charged with a fire extinguishing agent and intended for use in a fire
suppression are specifically excluded from transportation as ``UN1044,
fire extinguisher.'' Therefore, while HM-234 added provisions that may
allow hazardous materials in cylinders that have historically been
described and transported as UN1956 or UN3500 to be transported as
``UN1044, fire extinguisher'', amending Sec.  173.335 is still
necessary to maintain alignment with the UN Model Regulations because
the UN Model Regulations still do not allow cylinders intended for use
in fire suppression systems to be transported under UN1044.
---------------------------------------------------------------------------

    \25\ 85 FR 85380 (Dec., 28, 2020).
---------------------------------------------------------------------------

    Because of this conflict in classification for similar items, PHMSA
proposes to extend the periodic inspection period for cylinders
containing gases or liquid/gas mixtures that are used as fire
extinguishing agents under UN3500, to facilitate international shipment
of these items by aligning the Sec.  173.335 periodic inspection
requirements with the periodic inspection period adopted in the UN
Model Regulations. Recognizing that these items UN3500 and UN1044 are
functionally the same but classified differently outside of the United
States, PHMSA expects that establishing parallel inspections periods
for similar items will facilitate international movement and continued
use of these cylinders domestically and internationally.

D. Part 175

Section 175.8
    Part 175 of the HMR prescribes requirements that apply to the
transportation of hazardous materials in commerce aboard aircraft,
including items carried by air passengers and crew, as well as items
carried by the aircraft operator in accordance with airworthiness
requirements and operating regulations, or in support of in-flight
service. Section 175.8 provides exceptions from the HMR for certain
equipment and materials used by aircraft operators that are regulated
as hazardous materials. PHMSA proposes to amend paragraph (b) to
provide a new exception for alcohol-based hand sanitizers and alcohol-
based cleaning products carried aboard an aircraft by the operator for
the purposes of passenger and crew hygiene. The proposed changes align
the HMR with amendments made to the ICAO Technical Instructions, as
amended in Addendum 1, on December 31, 2020, in response to the COVID-
19 public health emergency. The intent of this amendment is to ensure
that air operators are able to equip aircraft with alcohol-based
sanitizers for use in the cabin for the purposes of passenger and crew
hygiene without the regulatory burden of documentation and packaging
otherwise associated with the transport of Class 3 flammable liquid
hazardous materials. This proposal is beneficial to public interest
given that it assists in limiting the spread and contraction of viruses
such as COVID-19 without an anticipated decrease in transportation
safety.
Section 175.9
    Section 175.9 provides exceptions from Subchapter C of the HMR for
certain special aircraft operations. Paragraph (b)(5) excepts organ
preservation units necessary to protect human organs when carried in
the aircraft cabin, provided certain conditions are met. As written,
the current provisions only allow for devices powered by non-spillable
batteries. However, the technology for powering such devices has
evolved to include lithium batteries. To maintain consistency with the
ICAO Technical Instructions, PHMSA proposes to add provisions for organ
preservation units powered by lithium batteries (both metal and ion).
Specifically, lithium metal or lithium ion cells or batteries must meet
the general provisions prescribed in Sec.  173.185(a) and spare lithium
batteries would need to be individually protected to prevent short
circuits when not in use to ensure safe transport and use of this
exception. PHMSA expects this proposed HMR amendment will promote
broader use of the exception for organ preservation units. Finally, it
facilitates international movement of these devices by harmonizing with
ICAO Technical Instructions which allow lithium batteries as a power
sources for the devices while still ensuring safe transport.
Section 175.10
    Section 175.10 specifies the conditions under which passengers,
crew members or an operator may carry hazardous materials aboard a
passenger aircraft. PHMSA proposes to amend paragraph (a)(1)(ii) of
this section to permit Division 2.2 aerosols with no subsidiary hazard
in addition to those that are not for medicinal or personal toiletry
use as carry-on items (see Sec.  175.10(a)(1)(i) in the HMR for
provisions pertaining to non-radioactive medicinal and toilet
articles). Currently, these materials (2.2 non-flammable gases) are
only authorized in checked baggage. Additionally, PHMSA proposes to add
a conditional requirement to new paragraph (a)(1)(iv) that the material
in the Division 2.2 aerosols must not cause extreme annoyance or
discomfort, in the event of an unintentional release, to crew members
so as to inhibit performance of their assigned duties. The proposed
changes align the HMR with amendments made to the ICAO Technical
Instructions. In addition, these proposed changes are consistent with
special permit DOT-SP 21021,\26\ which was issued in response to the
COVID-19 public health emergency to ensure flight crews could carry-on
sanitizing aerosol products that may not have been considered as items
for personal use. PHMSA has determined that this proposal is beneficial
and in the public interest because it expands the use of the passenger
and crewmember exceptions applicable to Division 2.2 aerosols by
allowing such aerosols in carry-on baggage. This is particularly
beneficial for sanitizers to aid in preventing the potential spread and
contraction of viruses such as COVID-19 without an anticipated decrease
in transportation safety.\27\
---------------------------------------------------------------------------

    \26\ DOT Special Permit 21021 (May 29, 2020), https://www.phmsa.dot.gov/approvals-and-permits/hazmat/file-serve/offer/SP21021.pdf/2020034999/SP21021.
    \27\ PHMSA notes that, apart from the revisions to Sec.  175.10
of the HMR proposed here, transportation of aerosols in carry-on
baggage and for any other purpose may be subject to limitations
imposed by other regulators, including (but not limited to) the
Transportation Security Administration.
---------------------------------------------------------------------------

    Section 175.10(a)(11) outlines the provisions for self-inflating
personal

safety devices and currently allows for the carriage of only one device
with the approval of the aircraft operator. PHMSA proposes to increase
the allowance from a single self-inflating personal safety device to
two devices in response to an increase in passengers seeking to travel
with their own devices. PHMSA clarifies that each self-inflating safety
device may be fitted with no more than two small gas cartridges and
that an additional two spare cartridges per device may be carried with
the devices. In addition, PHMSA proposes to add the text ``intended to
be worn by a person'' to specify that this provision is only intended
for self-inflating personal safety devices that are designed to be worn
by a person and does not apply to other types of safety devices. PHMSA
expects this proposal will promote use of the self-inflating personal
safety devices. Specifically, it provides passengers more flexibility
when carrying self-inflating devices such as life-jackets, motorcycle
jackets and horse riding vests. Further, PHMSA does not expect
transportation safety will be compromised as these devices are designed
with multiple initiation processes required for inflation to occur,
thereby inhibiting unintentional activation. PHMSA has not identified
any incidents involving unintentional activation of self-inflating
personal safety devices inflight.
Section 175.75
    Section 175.75 provides quantity limitations and stowage location
requirements for air transportation. During internal review of the
stowage requirements found in Sec.  175.75, PHMSA and FAA concluded
that several editorial revisions would increase the clarity of this
section, and therefore enhance the safety or hazardous materials
transported by aircraft. These proposed revisions do not substantively
change current requirements of this section. They are intended only for
purposes of increasing the understanding of air stowage requirements.
The proposed editorial revisions to this section are discussed as
follows:
     The current structure for paragraph (b) outlines three
distinct stowage requirements in a single paragraph. To increase
readability, PHMSA proposes to revise paragraph (b) by separating the
three requirements into three subparagraphs each addressing a single
stowage requirement.
     Insertion of an additional distinct sentence in the
aforementioned proposed revised format of paragraph (b) to highlight
the existing requirement in Sec.  175.75 that all packages displaying a
Cargo Aircraft Only label in accordance with Sec.  172.402(c) must be
loaded in an accessible manner (i.e., a manner accessible to the cargo
aircraft's crew or other authorized person). This longstanding
requirement of the HMR is buried in the Quantity and Loading Table of
paragraph (f). Air carrier stakeholders have suggested to PHMSA and FAA
that the stowage requirements would be clarified if this important
requirement were explicitly stated in Sec.  175.75. Therefore, PHMSA
proposes to specify this requirement in the stowage requirements as
subparagraph (b)(4).
     Correction of an inadvertent error in the Quantity and
Loading Table of paragraph (f), Note 1, that removed Division 6.2
material from eligibility for exception from the inaccessible loading
restriction for Cargo Aircraft Only packages. This inadvertent error
occurred in a corrections and response to administrative appeals final
rule.\28\ PHMSA revised requirements for Division 6.1 material among
the list of eligible materials but in doing so inadvertently removed
reference to Division 6.2 material. This change was not intended and;
therefore, PHMSA proposes to reinsert reference to Division 6.2
material in Note 1.
---------------------------------------------------------------------------

    \28\ 78 FR 65453 (Oct. 31, 2013). This rule affected rules HM-
215K, HM-215L, HM218G, and HM-219.
---------------------------------------------------------------------------

     Insertion of an Oxford comma in the Quantity and Loading
Table of paragraph (f), Note 1, item d. to more clearly indicate that
Class 9 material, limited quantity material, and excepted quantity
material all qualify for this provision. PHMSA and FAA are aware that
some air carrier stakeholders have expressed confusion with the
language in Note 1, item d., and acknowledge that the omission of a
comma between ``Limited Quantity'' and ``Excepted Quantity'' may create
the impression that only Class 9 limited or excepted quantity material
are eligible for this exception. Note 1, item d. has always included
all eligible hazard classes of limited quantity and excepted quantity
material.

E. Part 176

Section 176.84
    Part 176 contains requirements associated with transportation of
hazardous materials by vessel. Section 176.84 prescribes the meanings
of numbered or alphanumeric vessel transport stowage provisions that
are assigned to hazardous materials and which are listed in column
(10B) of the HMT. The provisions in Sec.  176.84 are separated into
general stowage provisions, which are defined in the ``table of
provisions'' in paragraph (b), and the stowage notes unique to vessel
shipments of Class 1 explosives, which are defined in the table in
paragraph (c)(2). PHMSA has determined that the following proposed
revisions will improve safety by ensuring that hazardous materials are
properly stowed on vessels.
    First, PHMSA proposes to revise stowage provision 4 in paragraph
(b). Existing stowage provision 4 directs shippers to ``Stow `Separated
from' liquid organic materials.'' PHMSA proposes to modify the language
in this code for clarity and to facilitate proper stowage. In a
proposal submitted to the IMO, it was noted that many liquid organic
materials are not dangerous goods and that it is difficult to identify
these commodities for purposes of segregation.\29\ Furthermore, the
distinction between organic and inorganic substances cannot be easily
discovered by persons responsible for the packing of a cargo transport
unit. PHMSA has determined that requiring a determination as to whether
a cargo is an organic or inorganic substance should be amended with a
more readily understood requirement to characterize these items as
combustible materials. This clarification would aid in ensuring safe
segregation of materials assigned this stowage provision. Therefore,
PHMSA proposes to amend stowage provision 4 to require materials
assigned this code to ``not be stowed'' with combustible materials in
the same cargo transport unit.
---------------------------------------------------------------------------

    \29\ International Maritime Organization Sub-Committee on the
Carriage of Cargoes and Containers CCC 5/6/3.
---------------------------------------------------------------------------

    Second, PHMSA proposes to add new stowage provisions under codes
155, 156, and 157:
     New stowage code 155 is assigned to ``UN2814, Infectious
substances, affecting humans'' and ``UN2900, Infectious substances,
affecting animals only.'' This new stowage provision advises vessel
carriers to avoid handling of an infectious package or keep handling of
the package to a minimum and to inform the appropriate public health
authority or veterinary authority where persons or animals may have
been exposed to the package contents. This provision may improve safety
for packages that may be used to transport COVID-19 related material.
Stowage code 155 would apply particularly to any cargo offered in the
traditional manner (i.e., break-bulk). The proposed stowage code
advises cargo handling personnel to limit interaction with packages of
Division 6.2 materials to a minimum. The requirement to notify the
appropriate public health authority or

veterinary authority where persons or animals may have been exposed to
package contents is intended to ensure appropriate medical attention
can be provided in the event of an exposure and any potential further
contamination as a result of contact with the material is controlled.
This new stowage code serves to ensure vessel carriers are aware of the
potential hazard of these packages and to ensure they follow all
protocols related to handling such packages.
     New stowage code 156 is assigned to ``UN3090, Lithium
metal batteries,'' ``UN3091, Lithium metal batteries contained in
equipment, or Lithium metal batteries packed with equipment,''
``UN3480, Lithium ion batteries,'' and ``UN3481, Lithium ion batteries
contained in equipment or Lithium ion batteries packed with
equipment.'' This new stowage provision would require damaged or
defective lithium batteries that are offered for transportation in
accordance with Sec.  173.185(f) or being transported for purposes of
disposal or recycling in accordance with proposed Sec.  172.203(i)(4),
to be stowed in accordance with stowage category C. Stowage category C
requires on deck stowage instead of the currently authorized on deck or
under deck stowage of these types of lithium batteries. This proposal
harmonizes HMR stowage requirements for lithium batteries that are
damaged/defective and those that are being offered for disposal or
recycling with the IMDG Code stowage requirements. This proposed
stowage change to require on deck stowage would allow for more easily
identifiable and effective response actions in the event of a fire
involving lithium batteries onboard a vessel. PHMSA expects that these
revised shipping requirements will contribute to the safe
transportation of increased volumes of lithium batteries anticipated as
a result of the increased use of those technologies in the
transportation and other economic sectors.
     New stowage code 157 is assigned to the five HMR UN1950
aerosol entries and the three UN2037 receptacles; small, containing gas
or gas cartridges entries. This new stowage provision would require
aerosols and receptacles for gas transported for recycling or disposal
to be stowed in accordance with vessel stowage category C and clear of
living quarters. The HMR does not currently contain separate stowage
provisions for aerosols or receptacles small containing gas that are
being offered for disposal or recycling. These materials are assigned
stowage category A if they are new and never used, or if they are
offered for transportation. The change from stowage category A to
category C means these materials being offered for recycling or
disposal would be required to be stowed ``on deck only'' instead of the
currently authorized ``on deck or under deck.'' This proposed change in
stowage requirements for aerosols and receptacles small containing gas
provides more restrictive stowage requirements for these articles that
have been utilized and are being offered for transportation under
generally more relaxed packaging standards than if they were being
offered as new articles. This more restrictive stowage requirement
would more easily facilitate a response effort should one be required
aboard a vessel.
    Third, in the paragraph (c)(2) table, PHMSA proposes amending
stowage provisions for notes 19E and 22E. When assigned to an HMT
entry, these existing notes require separation ``away from'' explosives
containing chlorates or perchlorates and ``away from'' ammonium
compounds and explosives containing ammonium compounds or salts. PHMSA
proposes to amend these stowage provisions to specify a more demanding
``separated from'' stowage requirement. The terms ``away from'' and
``separated from'' have various meanings based on the type of shipment
(e.g., break-bulk, shipments within a container, or container to
container). Generally speaking, the term ``separated from'' requires
more stringent segregation. As an example, for segregation from one
container to another if ``away from'' applies, the containers cannot be
stowed one on top of the other. If ``separated from'' is assigned, the
containers cannot be stowed in the same vertical line. For more
information on the applicability of these terms please, see Sec.
176.83 of the HMR. This proposal also harmonizes the HMR with the IMDG
Code and aligns with HMR stowage requirements for shipments of ammonium
nitrates, chlorates, and perchlorates. These proposed changes provide
additional segregation between loads of incompatible materials and
decrease the likelihood of a reaction if a release were to occur
onboard a vessel.

F. Part 178

Section 178.3
    Part 178 contains specifications for packagings. Section 178.3
prescribes marking requirements for specification packagings. PHMSA
proposes to amend paragraph (a)(4) to clarify the marking size
requirement for packagings transporting solids with a 30 kg (66 pounds)
maximum net mass. Additionally, PHMSA is proposing to amend the
exception for reducing the size of the required package marking
applicable to packagings with a capacity of 5 L or less, or of 5 kg
maximum net mass. The existing HMR text only refers to capacity, and
the proposed use of ``maximum net mass'' is a more appropriate standard
for packagings intended for solids. This editorial change is intended
to reduce confusion over the application of the reduce size marking
requirements as they apply to packagings used for solid materials. The
quantity limit should be based on the net amount of solid material and
not the capacity of the packaging the material is placed in. This
clarification is consistent with similar provisions for solids (net
mass) and liquids (capacity) throughout the HMR. Ensuring the
appropriate application of the reduced size marking allowance provides
consistency across persons using the reduce sized marking and
therefore, improves safety of transport.
Section 178.71
    Section 178.71 prescribes specifications for UN pressure
receptacles. To maintain consistency with the UN Model Regulations,
PHMSA proposes to update four ISO documents incorporated by reference
in this section.
    First, PHMSA proposes to amend paragraph (d)(2), which outlines the
configuration and design requirements for a cylinder's service
equipment, and includes items that prevent the release of the pressure
receptacle contents during handling and transportation. Currently this
paragraph requires that valves for service equipment must conform to
the 1999, 2006 and 2014 editions of ISO 10297. ISO 10297 specifies
design, type testing and marking requirements for cylinder valves
fitted to refillable transportable gas cylinders, main valves for
cylinder bundles, and cylinder valves or main valves with an integrated
pressure regulator (VIPR), which convey compressed, liquefied, or
dissolved gases. PHMSA proposes to modify the valve conformance
requirements in this paragraph such that when the use of a valve is
prescribed, the valve must conform to the requirements of ISO
10297:2014 and the supplemental amendment, ISO 10297:2014/Amd 1:2017.
ISO 10297:2014/Amd 1:2017 corrects errors in ISO 10297:2014 and also
includes modifications for valves for tubes and pressure drums. PHMSA
has reviewed this supplemental amendment as part of its regular
participation in the review of amendments proposed for the UN

Model Regulations and does not expect any degradation of safety
standards in association with the use of these two documents.
Additionally, PHMSA proposes to add an end date of December 31, 2022 to
the authorization to use ISO 10297:2014 when not used in conjunction
with the supplemental 2017 amendment, ISO 10297:2014/Amd 1:2017.
    Also in this paragraph, PHMSA proposes to amend references to ISO
14246, ``Gas cylinders--Cylinder valves--Manufacturing tests and
examinations.'' Currently paragraph (d)(2) states that valves must be
initially inspected and tested in accordance with ISO 14246:2014(E),
``Gas cylinders--Cylinder valves--Manufacturing tests and
examinations.'' However, in 2017, ISO published ISO 14246:2014/Amd
1:2017, ``Gas cylinders--Cylinder valves--Manufacturing tests and
examinations,'' which provides supplemental amendments pertaining to
specific pressures to be used in the pressure test and leakproofness
test of acetylene valves. PHMSA proposes to require the use of this
amended document in Sec.  178.71 to require acetylene valve users to
use the updated values in ISO 14246:2014/Amd 1:2017. PHMSA has reviewed
these documents as part its regular participation in the review of
amendments proposed for the UN Model Regulations and does not expect
any degradation of safety standards in association with the use of
these two documents. PHMSA also proposes to add analogous compliance
requirements for self-closing valves to paragraph (d)(2). ISO
17879:2017--Gas cylinders--Self-closing cylinder valves--Specification
and type testing, specifies the design, type testing, marking, and
manufacturing tests and examinations requirements for self-closing
cylinder valves intended to be fitted to refillable transportable gas
cylinders which convey compressed, liquefied, or dissolved gases.
    Additionally, PHMSA proposes to amend paragraph (l)(1), which
specifies the design and construction requirements for UN composite
cylinders and tubes. The proposed change would add a new subparagraph
(iv) to reference ISO 11119-4:2016, ``Gas cylinders--Refillable
composite gas cylinders--Design, construction and testing--Part 4:
Fully wrapped fibre reinforced composite gas cylinders up to 150 L with
load-sharing welded metallic liners.'' This document, which was adopted
in the UN Model Regulations, specifies requirements for composite gas
cylinders with load-sharing welded liners between 0.5 L and 150 L water
capacity and a maximum test pressure of 450 bar for the storage and
transportation of compressed or liquefied gases. PHMSA incorporates by
reference the first three parts of the ISO 11119 series, which cover
various designs of composite cylinders with a seamless liner. This
fourth part defines the requirements for design, construction, and
testing of composite cylinders with a welded metallic liner.
Incorporating this ISO standard would eliminate the need and associated
burden for manufacturers to request a special permit to construct fully
wrapped fiber reinforced composite gas cylinders with load-sharing
welded steel liners.\30\
---------------------------------------------------------------------------

    \30\ See, e.g., Special Permit 14457 (Dec. 16, 2019), which
served as the technical basis for the development of ISO 11119-
4:2016.
---------------------------------------------------------------------------

    Finally, PHMSA proposes to amend paragraph (o)(1) of this section
to update the reference to ISO 11114-1:2012(E), ``Gas cylinders--
Compatibility of cylinder and valve materials with gas contents--Part
1: Metallic materials.'' ISO 11114-1:2012 provides requirements for the
selection of safe combinations of metallic cylinder and valve materials
and cylinder gas content. PHMSA proposes to amend the compatibility
requirements to also require compatibility with the 2017 supplement to
ISO 11114-1:2012, (ISO 11114-1:2012/Amd 1:2017) for material
compatibility requirements. Permitting the use of this document would
allow shippers to safely transport a wider variety of gases in newly
developed types of metallic cylinders and valves. PHMSA has reviewed
this document as part of its regular participation in the review of
amendments proposed for the 21st revised edition of the UN Model
Regulations and expects that adding it to the HMR will enhance the
current safety of hazardous materials in transportation, in addition to
harmonizing the HMR with international requirements. This amendment
provides compatibility requirements for the selection of combinations
of metallic cylinder and valve materials for use with gas or gas
mixtures. In the interest of providing uniformity with regard to
reference standards used domestically and internationally, PHMSA
proposes to revise the compatibility requirements to also refer to the
2017 amendment of this ISO standard. This 2017 supplemental amendment
provides more explicit instructions on the permissible concentrations
of certain gases. PHMSA has determined that permitting the use of this
updated document would allow safe transport of a wider variety of gases
in newly developed types of metallic cylinders and valves without
compromising safety.
Section 178.75
    Section 178.75 prescribes specifications for multiple-element gas
containers (MEGCs), which are assemblies of UN cylinders, tubes, or
bundles of cylinders interconnected by a manifold and assembled within
a framework. The term includes all service equipment and structural
equipment necessary for the transport of gases including hazardous
materials marked as Division 2.1 (such as compressed hydrogen). PHMSA
proposes to revise paragraph (d) to permit explicitly the use of
composite construction, which is allowed for other pressure vessels
(i.e., cylinders), rather than limiting authorized material of
construction for an MEGC to seamless steel as in the current HMR.
Composite cylinders are constructed of carbon, fiberglass, or a hybrid
composite with high-strength aluminum liners. When the specifications
for MEGCs were originally created, there were no standards for
composite pressure receptacles in the international transport standards
or the HMR. In the decades since standards for the use of ISO composite
pressure receptacles have since been developed and authorized.
International standards did not consider a corresponding allowance to
use these composite pressure receptacles as elements of MEGCs when the
specifications were originally adopted. The 21st revised edition of the
UN Model Regulations have since been updated to include such an
authorization and PHMSA proposes to similarly allow the use of
composite pressure receptacles in MEGCs.
    To that end, PHMSA is adding references to the following ISO design
standards for composite MEGCs: ISO 11119-1:2012(E), ``Gas cylinders--
Refillable composite gas cylinders and tubes--Design, construction and
testing--Part 1: Hoop wrapped fibre reinforced composite gas cylinders
and tubes up to 450 L,'' ISO 11119-2:2012(E), ``Gas cylinders--
Refillable composite gas cylinders and tubes--Design, construction and
testing--Part 2: Fully wrapped fibre reinforced composite gas cylinders
and tubes up to 450 l with load-sharing metal liners,'' and ISO 11119-
3:2013(E), ``Gas cylinders--Refillable composite gas cylinders and
tubes--Design, construction and testing--Part 3: Fully wrapped fibre
reinforced composite gas cylinders and tubes up to 450 L with non-load-
sharing metallic or non-metallic liners.'' The 19th revised edition of
the Model Regulations

amended the definition of a tube to include composite construction and
this change also included standards for the construction of composite
tubes. Due to the lack of any technical or safety concerns, the 21st
revised edition of the UN Model Regulations included an amendment to
the definition of MEGCs which provides for composite construction, in
addition to stainless steel construction and were not intended to
exclude MEGCs. With these proposed revisions, PHMSA expects that this
will provide flexibility and opportunities for cost savings for
manufacturers of MEGCs while not compromising safety. Additionally,
authorizing alternative MEGC packaging construction would provide
flexibility in packaging selection for shippers that could facilitate
the transportation of hydrogen or other gases that may be used to
support clean energy alternatives.
Section 178.275
    Section 178.275 outlines requirements and definitions pertaining to
UN portable tanks intended for the transportation of liquid and solid
hazardous materials. Paragraph (i) specifies the capacity requirements
for pressure relief devices that must be on these portable tanks. The
HMR specify a formula that can be used to determine the required total
capacity for these pressure relief devices. The formula defines
variable ``U'' as ``thermal conductance of the insulation.''
Discussions held by the UNSCOE \31\ led to the conclusion that usage of
the phrase ``thermal conductance'' associated with the variable ``U''
in this formula is misleading because, in general scientific usage,
``conductance'' is expressed in ``kW. K-1'', and is not a
surface factor. Leaving the formula description as it currently appears
in the HMR may cause confusion for those who use it given that the
correct term for the unit given is ``heat transfer coefficient.'' PHMSA
proposes to replace the phrase ``thermal conductance'' with ``heat
transfer coefficient'' so that ``U'' is defined as ``heat transfer
coefficient of the insulation'' which is more appropriate for what is
being calculated and is consistent with use of the formula in the UN
Model Regulations. This would ensure proper calculation of the total
capacity for the pressure relief devices for these portable tanks.
---------------------------------------------------------------------------

    \31\ ``Use of the terms ``conductivity'' and ``conductance'' in
chapter 6.7'' https://www.unece.org/fileadmin/DAM/trans/doc/2018/dgac10c3/ST-SG-AC.10-C.3-2018-56e.pdf.
---------------------------------------------------------------------------

Section 178.505
    Section 178.505 prescribes specifications for aluminum drums and
paragraph (b) prescribes the construction requirements for those
aluminum drums. PHMSA proposes to add a new paragraph (b)(6) to specify
conditions when internal protective coatings or treatments must be
applied to these drums--consistent with requirements for other metal
packagings, such as steel drums, as provided in Sec.  178.504(b)(7) and
aluminum and steel jerricans in Sec.  178.511(b)(5). PHMSA agrees that,
since metals are susceptible to corrosion from exposure to certain
chemicals (e.g., sodium hydroxide solution, or alkaline liquids),
measures need to be taken to ensure the packaging is compatible with
the contents. Further, the general requirements for packagings in the
HMR include a compatibility requirement such that even though certain
packagings are specified in the HMR, it is, nevertheless, the
responsibility of the person offering a hazardous material for
transportation to ensure that such packagings are compatible with their
contents. This applies particularly to corrosivity, permeability,
softening, premature aging, and embrittlement (see Sec.  173.24(e)).
Therefore, PHMSA proposes to add conditions when internal protective
coatings or treatments must be applied to metal drums that are not
constructed of steel or aluminum. This addition is consistent with
international standards covering UN packages 1B1 and 1B2 aluminum
drums. PHMSA expects that this proposal will improve consistency with
regard to safety standards (e.g., packaging integrity) across similar
packagings.
Section 178.506
    Section 178.506 prescribes specifications for metal drums that are
not made of steel or aluminum, and paragraph (b) prescribes the
construction requirements for these drums. PHMSA proposes to add a new
paragraph (b)(6) to specify conditions when internal protective
coatings or treatments must be applied to metal drums that are not
constructed of steel or aluminum consistent with this requirement for
specifications of other metal packagings. This new requirement would
mirror the requirements to apply suitable internal protective coatings
or treatments in Sec.  178.504(b)(7) for steel drums and Sec.
178.511(b)(5) for aluminum and steel jerricans. Since metals are
susceptible to corrosion from exposure to certain chemicals (e.g.,
sodium hydroxide solution, or alkaline liquids), PHMSA has determined
measures need to be taken to ensure the packaging is compatible with
the contents. Further, the general requirements for packagings in the
HMR include a compatibility requirement such that even though certain
packagings are specified in the HMR, it is, nevertheless, the
responsibility of the person offering a hazardous material for
transportation to ensure that such packagings are compatible with their
contents. This applies particularly to corrosivity, permeability,
softening, premature aging, and embrittlement (see Sec.  173.24(e)).
However, PHMSA expects that codifying specific conditions in which
internal protective coatings or treatments must be applied to metal
drums that are not constructed of steel or aluminum will provide needed
consistency by providing uniform safety standards for similar
packagings across the HMR and ensure safe packaging and transport
within these metal drums.
Section 178.609
    Section 178.609 provides test requirements for packagings for
infectious substances. PHMSA proposes an editorial amendment in
paragraph (g) to clarify the performance testing requirements for
infectious substances packaging. Specifically, PHMSA proposes to amend
paragraph (g) to clarify that only one additional test is required for
packages for infectious substances containing dry ice. The 21st revised
edition of the UN Model Regulations made a similar clarification
regarding the testing requirements for these packagings and PHMSA has
determined that the current HMR also contains conflicting language in
Sec.  178.609. Currently paragraph (g), which specifies additional
testing requirement for packagings intended to contain dry ice, may be
interpreted to either require five additional samples dropped once
each, or one additional sample packaging dropped five times. However,
requiring one sample to be dropped five times in one orientation would
not be consistent with drop testing requirements applicable to other
packagings. PHMSA proposes to amend paragraph (g) to clearly state only
one additional sample must be dropped in a single orientation; namely,
the orientation the tester determines would be most likely to result in
failure of the packaging in light of the properties of the packaging
and the test surface. PHMSA does not consider this change to be
technical, but editorial, with the intent of conveying the testing
protocol, as it was designed, more clearly. For that reason, PHMSA does
not expect any change in level of safety than what

was originally intended. This change would simply result in a package
being tested in line with the design of the original packaging test
method.
Section 178.703
    Section 178.703 outlines the marking requirements for intermediate
bulk containers (IBCs). PHMSA proposes to amend two marking
requirements in this Section.
    In paragraph (b)(6), which specifies additional marking
requirements for composite IBCs, the amendment would specify that the
required markings on inner receptacles of these packagings must either
be readily visible while in the outer casing or duplicated on the outer
casing to facilitate inspection verifying compliance with the
applicable package performance standard marking requirements.
    In paragraph (b)(7), which outlines the marking requirements for
IBCs that are designed to be stacked, PHMSA proposes to revise language
in paragraph (b)(7)(iv) to clarify the maximum stacking load
requirements pertaining to each marking requirement. Currently
paragraph (b)(7)(iv) indicates that the maximum permitted stacking load
``applicable when the IBC is in use,'' must be displayed. PHMSA has
determined that this phrase may be misinterpreted to mean that the
stacking load applies only to transportation, leading to these
packagings being stacked inappropriately when not in transportation,
such as in warehouse storage. PHMSA proposes to remove the words
``applicable when the IBC is in use,'' to clarify that stacking loads
should never be exceeded whether in transportation or in storage. PHMSA
has determined that clarifying the regulatory text regarding the proper
use of these packagings will provide an enhanced level of safety both
during transport and during storage.
Section 178.705
    Section 178.705 prescribes specifications for metal IBCs. Paragraph
(c) outlines construction requirements and paragraph (c)(1)(iv)
specifies the minimum wall thickness requirements for metal IBCs. Metal
IBCs are currently the only type of IBCs for which there are minimum
wall thickness requirements, which is likely a holdover from
regulations for cubical tank containers, from which the metal IBCs were
once derived.\32\ In contrast, because of performance testing
requirements' (i.e., drop, stack and vibration) ability to demonstrate
the integrity of the package, the 21st revised edition of the UN Model
Regulations include an amendment which now provides that minimum wall
thickness requirements apply only to metal IBCs that have a capacity of
more than 1500 L (396 gallons), while metal IBCs with a volume of 1500
L or less are no longer subject to previous prescriptive minimum wall
thickness requirements.
---------------------------------------------------------------------------

    \32\ Stainless Steel Container Association, Proposal on Minimum
Wall Thickness for Metal IBCs Submitted to the Sub-Committee of
Experts on the Transport of Dangerous Goods During the 54th Session
(Sep. 7, 2018), https://www.unece.org/fileadmin/DAM/trans/doc/2018/dgac10c3/ST-SG-AC.10-C.3-2018-96e.pdf.
---------------------------------------------------------------------------

    Therefore, PHMSA proposes to revise the minimum wall thickness
requirements for metal IBCs with a volume of 1500 L or less to provide
additional design and construction flexibility with regards to IBC
designs. This amendment would harmonize with the 21st revised edition
of the UN Model Regulations. PHMSA solicits comments on the following
safety and economic impacts regarding this proposed amendment:
     Does the reliance on the performance testing system and
the elimination of a prescriptive minimum wall thickness for metal
IBC's with a capacity of 1500 L or less present an unnecessary safety
risk (e.g., reduced corrosion protection, ability to prevent punctures
or ruptures resulting from conditions normally incident to
transportation)? Explain.
     Do manufacturers primarily use a reference steel or are
other steels commonly used? If so, which ones?
     If the minimum thickness requirement were removed for
metal IBCs with a capacity of 1500 L or less, what calculations will
the manufacturers use to determine the design minimum thickness for the
IBCs made from the reference steel?
     What is an approximate number of metal IBC design types
and the number of IBCs manufactured in accordance with these design
types that could reasonably expected to be in transportation?
     What is the expected cost savings from the removal of a
minimum wall thickness requirement for IBCs at or below the proposed
1500 L capacity?
     What are the expected impacts of not harmonizing HMR
requirements for metal IBCs with a capacity of 1500 L or less?
    As an alternative to the proposed rule, PHMSA is also considering a
change to Sec.  171.23, which prescribes requirements for specific
materials and packagings transported under incorporated international
standards to prohibit transportation or offering for transportation of
metal IBCs with a capacity of 1500 L or less when that transportation
is made in accordance with the ICAO Technical Instructions, IMDG Code,
Transport Canada TDG Regulations, or the IAEA Regulations. PHMSA also
solicits comments on that potential prohibition.

G. Part 180

Section 180.207
    Section 180.207 outlines the requirements for the requalification
of UN pressure receptacles. Paragraph (d) specifies the requalification
procedures for various types of UN cylinders but, consistent with
historical approach of the UN Model Regulations, does not include any
procedures for the periodic inspection of UN cylinder bundles. However,
the 21st revised edition of the UN Model Regulations addressed that gap
by adding a new reference document entitled ISO 20475: 2018 ``Gas
cylinders--Cylinder bundles--Periodic inspection and testing.'' ISO
20475 provides detailed procedures for maintenance and periodic
inspection of cylinder bundles.
    PHMSA proposes to add paragraph (d)(7) to reference ISO 20475:2018,
``Gas cylinders--Cylinder bundles--Periodic inspection and testing'' to
provide a requalification standard for UN cylinder bundles because
requalification procedures may differ for bundles of cylinders versus
individual cylinders. This document was developed based on the need for
a standard specific to cylinder bundles which would allow them to be
reintroduced into service for an extended period of time. PHMSA expects
that incorporating by reference a safety standard for requalification
will reduce business costs and environmental effects by allowing
existing cylinders to be reintroduced into service for continued use.
As a participant on the UNSCOE, this standard was reviewed by PHMSA and
other international bodies for inclusion in the UN Model Regulations
based on its need and safety merit. Incorporating by reference ISO
20475 in the HMR is necessary, not only for international
harmonization, but also to address the lack of such a standard in the
HMR. Additionally, PHMSA proposes to remove a reference to the
outdated, third edition of ISO 10462(E), ``Gas cylinders--Transportable
cylinders for dissolved acetylene--Periodic inspection and
maintenance'' in paragraph (d)(3) used for the requalification of
dissolved acetylene cylinders. Requalification is required in
accordance with the third edition of ISO 10462:2013(E); however,
requalification

in accordance with the second edition was authorized until December 31,
2018 in 180.207(d)(3). This date has since passed and, therefore, PHMSA
proposes removing reference from this Section of the HMR. Consistent
with this revision, the incorporation by reference of the second
edition is removed from Sec.  171.7(w) of the HMR. Additionally,
acetylene cylinders requalified in accordance with the second edition
before December 31, 2018, must be subsequently requalified in
accordance with referenced third edition. PHMSA expects that these
amendments will enhance safety by providing cylinder users with the
necessary guidelines for the continued use of UN cylinders.
    The proposed regulatory text references ISO 10462:2013(E), which
was previously approved for incorporation by reference in this section,
and no changes are proposed for this standard.

VI. Regulatory Analyses and Notices

A. Statutory/Legal Authority for This Rulemaking

    This NPRM is published under the authority of Federal hazardous
materials transportation law. Section 5103(b) authorizes the Secretary
of Transportation to prescribe regulations for the safe transportation,
including security, of hazardous materials in intrastate, interstate,
and foreign commerce. Additionally, 49 U.S.C. 5120 authorizes the
Secretary to consult with interested international authorities to
ensure that, to the extent practicable, regulations governing the
transportation of hazardous materials in commerce are consistent with
the standards adopted by international authorities. The Secretary has
delegated the authority granted in the Federal hazardous materials
transportation law to the PHMSA Administrator at 49 CFR 1.97(b).

B. Executive Order 12866 and DOT Regulatory Policies and Procedures

    Executive Order 12866 (``Regulatory Planning and Review'') \33\
requires agencies to regulate in the ``most cost-effective manner,'' to
make a ``reasoned determination that the benefits of the intended
regulation justify its costs,'' and to develop regulations that
``impose the least burden on society.'' Similarly, DOT Order 2100.6A
(``Policies and Procedures for Rulemakings'') requires that PHMSA
rulemaking actions include ``an assessment of the potential benefits,
costs, and other important impacts of the regulatory action,'' and (to
the extent practicable) the benefits, costs, and any significant
distributional impacts, including any environmental impacts.
---------------------------------------------------------------------------

    \33\ 58 FR 51735 (Oct. 4, 1993).
---------------------------------------------------------------------------

    Executive Order 12866 and DOT Order 2100.6A require that PHMSA
submit ``significant regulatory actions'' to the Office of Management
and Budget (OMB) for review. This rulemaking is not considered a
significant regulatory action under section 3(f) of Executive Order
12866 and, therefore, was not formally reviewed by OMB. This rulemaking
is also not considered a significant rule under DOT Order 2100.6A.
    The following is a brief summary of costs, savings and net benefits
of some of the amendments proposed in this notice. PHMSA has developed
a more detailed analysis of these costs and benefits in the preliminary
regulatory impact analysis (PRIA), a copy of which has been placed in
the docket. PHMSA seeks public comment on its proposed revisions to the
HMR and the preliminary cost and benefit analyses in the PRIA.
    PHMSA proposes to amend the HMR to maintain alignment with
international regulations and standards, thereby maintaining the high
safety standard currently achieved under the HMR, facilitating the safe
transportation of critical vaccines and other medical materials
associated with the response to the COVID-19 public health emergency,
and aligning HMR requirements with anticipated increases in the volume
of lithium batteries transported in interstate commerce from
electrification of the transportation and other economic sectors. PHMSA
examined the likely impacts of finalizing and implementing the
provisions proposed in the NPRM in order to assess the benefits and
costs of these amendments. This analysis allowed PHMSA to
quantitatively assess the material effects of three of the proposed
amendments in the rulemaking. The effects of six remaining proposed
amendments are not quantified but are assessed qualitatively.
    PHMSA estimates that the annualized quantified net cost savings of
this rulemaking, using a 7 percent discount rate, are approximately
$23.5 to $28.5 million per year. The following table presents a summary
of the monetized impacts that these proposed changes may have upon
codification.

                                                           Summary Table of Net Regulatory Cost Savings, Discount Rate = 7%, 2022-2031
                                                                                [$2019]
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
                                              10 year costs        10 year cost savings      10 year net cost savings       Annual costs         Annual cost savings     Annual net cost savings
             Rule amendments             -------------------------------------------------------------------------------------------------------------------------------------------------------
                                             Low        High         Low          High           Low          High         Low        High        Low          High         Low          High
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Amendment 2: Electric and Electronic       $618,355   $811,662             0             0    ($618,355)    ($811,662)    $88,040   $115,562            0            0    ($88,040)   ($115,562)
 Detonators.............................
Amendment 5: Lithium Battery Mark.......          0          0   159,315,195   173,458,922   159,315,195   173,458,922          0          0   22,682,900   24,696,648   22,682,900   24,696,648
Amendment 7: Data Loggers...............          0          0     6,257,717    27,622,576     6,257,717    27,622,576          0          0      890,958    3,932,833      890,958    3,932,833
                                         -------------------------------------------------------------------------------------------------------------------------------------------------------
    Total...............................    618,355    811,662   165,572,913   201,081,499   164,954,558   200,269,837     88,040    115,562   23,573,858   28,629,482   23,485,818   28,513,919
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

    The safety and environmental benefits of the proposed rule have not
been quantified. However, PHMSA expects the proposed amendments would
help to improve public safety and reduce the risk of environmental harm
by maintaining consistency between these international regulations and
the HMR. Harmonization of the HMR with international consensus
standards as proposed could reduce delays and interruptions of
hazardous materials during transportation, thereby lowering GHG
emissions and safety risks to communities (including minority, low-
income, underserved, and other disadvantaged populations and
communities) in the vicinity of interim storage sites and
transportation arteries and hubs.

C. Executive Order 13132

    PHMSA analyzed this rulemaking in accordance with the principles
and criteria contained in Executive Order 13132 (``Federalism'') \34\
and the Presidential memorandum (''Preemption'') that was published in
the Federal Register on May 22, 2009.\35\ Executive Order 13132
requires agencies to assure meaningful and timely input by State and
local officials in the development of regulatory policies that may have
``substantial direct effects on the States, on the relationship between
the national government and the States, or on the distribution of power
and responsibilities among the various levels of government.''
---------------------------------------------------------------------------

    \34\ 64 FR 43255 (Aug. 10, 1999).
    \35\ 74 FR 24693 (May 22, 2009).
---------------------------------------------------------------------------

    The rulemaking may preempt State and local, and Native American
Tribe requirements, but does not propose any regulation that has
substantial direct effects on the States, the relationship between the
national government and the States, or the distribution of power and
responsibilities among the various levels of government. The Federal
hazardous materials transportation law contains an express preemption
provision at 49 U.S.C. 5125(b) that preempts State, local, and Tribal
requirements on certain covered subjects, unless the non-Federal
requirements are ``substantively the same'' as the Federal
requirements, including the following:
    (1) The designation, description, and classification of hazardous
material;
    (2) The packing, repacking, handling, labeling, marking, and
placarding of hazardous material;
    (3) The preparation, execution, and use of shipping documents
related to hazardous material and requirements related to the number,
contents, and placement of those documents;
    (4) The written notification, recording, and reporting of the
unintentional release in transportation of hazardous material; and
    (5) The design, manufacture, fabrication, inspection, marking,
maintenance, recondition, repair, or testing of a packaging or
container represented, marked, certified, or sold as qualified for use
in transporting hazardous material in commerce.
    This proposed rule addresses covered subject items (1), (2), (3),
(4), and (5) above and would preempt State, local, and Tribal
requirements not meeting the ``substantively the same'' standard. In
this instance, the preemptive effect of the proposed rule is limited to
the minimum level necessary to achieve the objectives of the hazardous
materials transportation law under which the final rule is promulgated.
Therefore, the consultation and funding requirements of Executive Order
13132 do not apply.

D. Executive Order 13175

    PHMSA analyzed this rulemaking in accordance with the principles
and criteria contained in Executive Order 13175 (``Consultation and
Coordination with Indian Tribal Governments'') \36\ and DOT Order
5301.1 (``Department of Transportation Policies, Programs, and
Procedures Affecting American Indians, Alaska Natives, and Tribes'').
Executive Order 13175 and DOT Order 5301.1 require DOT Operating
Administrations to assure meaningful and timely input from Native
American Tribal government representatives in the development of rules
that significantly or uniquely affect Tribal communities by imposing
``substantial direct compliance costs'' or ``substantial direct
effects'' on such communities or the relationship and distribution of
power between the Federal government and Native American Tribes.
---------------------------------------------------------------------------

    \36\ 65 FR 67249 (Nov. 9, 2000).
---------------------------------------------------------------------------

    PHMSA assessed the impact of the rulemaking and determined that it
would not significantly or uniquely affect Tribal communities or Native
American Tribal governments. The changes to the HMR proposed in this
NPRM are facially neutral and would have broad, national scope; PHMSA,
therefore, expects this rulemaking not to significantly or uniquely
affect Tribal communities, much less impose substantial compliance
costs on Native American Tribal governments or mandate Tribal action.
And because PHMSA expects the rulemaking would not adversely affect the
safe transportation of hazardous materials generally, PHMSA does not
expect it would entail disproportionately high adverse risks for Tribal
communities. For these reasons, PHMSA does not expect the funding and
consultation requirements of Executive Order 13175 and DOT Order 5301.1
to apply. However, PHMSA solicits comment from Native American Tribal
governments and communities on potential impacts of the proposed
rulemaking.

E. Regulatory Flexibility Act and Executive Order 13272

    The Regulatory Flexibility Act (5 U.S.C. 601 et seq.) requires
agencies to review proposed regulations to assess their impact on small
entities, unless the agency head certifies that a proposed rulemaking
will not have a significant economic impact on a substantial number of
small entities including small businesses, not-for-profit organizations
that are independently owned and operated and are not dominant in their
fields, and governmental jurisdictions with populations under 50,000.
The Regulatory Flexibility Act directs agencies to establish exceptions
and differing compliance standards for small businesses, where possible
to do so and still meet the objectives of applicable regulatory
statutes. Executive Order 13272 (``Proper Consideration of Small
Entities in Agency Rulemaking'') \37\ requires agencies to establish
procedures and policies to promote compliance with the Regulatory
Flexibility Act and to ``thoroughly review draft rules to assess and
take appropriate account of the potential impact'' of the rules on
small businesses, governmental jurisdictions, and small organizations.
The DOT posts its implementing guidance on a dedicated web page.\38\
---------------------------------------------------------------------------

    \37\ 67 FR 53461 (Aug. 16, 2002).
    \38\ DOT, ``Rulemaking Requirements Related to Small Entities,''
https://www.transportation.gov/regulations/rulemaking-requirements-concerning-small-entities (last accessed June 17, 2021).
---------------------------------------------------------------------------

    This proposed rulemaking has been developed in accordance with
Executive Order 13272 and with DOT's procedures and policies to promote
compliance with the Regulatory Flexibility Act to ensure that potential
impacts of draft rules on small entities are properly considered. This
proposed rule facilitates the transportation of hazardous materials in
international commerce by providing consistency with international
standards. It applies to offerors and carriers of hazardous materials,
some of whom are small entities, such as chemical manufacturers, users,
and suppliers,

packaging manufacturers, distributors, and training companies. As
discussed at length in the PRIA in the rulemaking docket, the
amendments in this proposed rule should result in net cost savings that
would ease the regulatory compliance burden for those and other
entities engaged in domestic and international commerce, including
trans-border shipments within North America. Additionally, the changes
proposed in this NPRM would relieve U.S. companies, including small
entities competing in foreign markets, from the burden of complying
with a dual system of regulations. Therefore, PHMSA expects that these
amendments will not, if adopted, have a significant economic impact on
a substantial number of small entities. However, PHMSA solicits
comments on the anticipated economic impacts to small entities.

F. Paperwork Reduction Act

    Under the Paperwork Reduction Act of 1995 (44 U.S.C. 3501 et seq.),
no person is required to respond to an information collection unless it
has been approved by OMB and displays a valid OMB control number.
Pursuant to 44 U.S.C. 3506(c)(2)(B) and 5 CFR 1320.8(d), PHMSA must
provide interested members of the public and affected agencies with an
opportunity to comment on information collection and recordkeeping
requests.
    PHMSA has analyzed this NPRM in accordance with the Paperwork
Reduction Act. PHMSA currently accounts for shipping paper burdens
under OMB Control Number 2137-0034, ``Hazardous Materials Shipping
Papers and Emergency Response Information.'' PHMSA proposes a number of
amendments that may impact the burden accounted for in OMB Control
Number 2137-0034. They include requiring the word ``stabilized'' as a
part of the proper shipping name for ``UN2522, 2-Dimethlaminoethl
methacrylate,'' adding the applicable term ``DAMAGED/DEFECTIVE,''
``LITHIUM BATTERIES FOR DISPOSAL'' or ``LITHIUM BATTERIES FOR
RECYCLING'', excepting marine pollutants from the requirement to
supplement the proper shipping name with a technical name for UN3077
and UN3082, and requiring documentation of the holding time for
refrigerated liquefied gases transported in portable tanks. However,
while PHMSA estimates that there will be some impact in the annual
burden related to shipping papers, PHMSA expects the overall impact to
annual burden is negligible in relation to the number of burden hours
currently associated with this information collection.
    OMB Control Number 2137-0051, ``Rulemaking, Special Permits, and
Preemption Requirements,'' currently accounts for burden associated
with petitions for rulemaking, special permit applications, and
preemption requests. PHMSA proposes to authorize certain ISO standard
valves in Sec.  173.301b(c)(2) and expand Sec.  175.10 to allow
passenger and crewmembers to carry certain Division 2.2 aerosols in
carry-on baggage, both of which eliminate the need for use of a special
permit. While PHMSA expects these proposals to reduce the burden
associated with this information collection, PHMSA anticipates the
reduction is negligible in relation to the total burden hours
associated with special permit applications.
    PHMSA accounts for the burden from approval applications in OMB
Control Number 2137-0557, ``Approvals for Hazardous Materials.'' PHMSA
proposes to add a new HMT entry for ``UN3549, Medical Waste, Category
A, Affecting Humans, solid or Medical Waste, Category A, Affecting
Animals only, solid'' and require an approval for transportation in
accordance with Special Provision 131, which PHMSA expects would
increase the number of annual approval applicants. PHMSA also proposes
to add new entries to the Sec.  173.225 Organic Peroxide Table, which
PHMSA expects would decrease the number of annual approval applicants.
However, PHMSA expects that these proposed changes are negligible to
the overall impact of the total burden in relation to the number of
burden hours associated with this information collection.
    PHMSA requests comments on the information collection and
recordkeeping burdens associated with developing, implementing, and
maintaining the proposed requirements in this NPRM. Address written
comments to the DOT Docket Operations Office identified in the
ADDRESSES section of this rulemaking. PHMSA must receive comments
regarding information collection burdens prior to the close of the
comment period identified in the DATES section of this rulemaking.
Requests for a copy of this information collection should be directed
to Steven Andrews or Shelby Geller, Standards and Rulemaking Division
(PHH-10), Pipeline and Hazardous Materials Safety Administration, 1200
New Jersey Avenue SE, Washington, DC 20590-0001. If these proposed
requirements are adopted in a final rule, PHMSA will submit the revised
information collection and recordkeeping requirements to OMB for
approval.

G. Regulation Identifier Number

    A regulation identifier number (RIN) is assigned to each regulatory
action listed in the Unified Agenda of Federal Regulatory and
Deregulatory Actions (``Unified Agenda''). The Regulatory Information
Service Center publishes the Unified Agenda in April and October of
each year; the most recent version was published in June 2021. The RIN
contained in the heading of this document can be used to cross-
reference this action with the Unified Agenda.

H. Unfunded Mandates Reform Act of 1995

    The Unfunded Mandates Reform Act of 1995 (UMRA; 2 U.S.C. 1501 et
seq.) requires agencies to assess the effects of Federal regulatory
actions on State, local, and Tribal governments, and the private
sector. For any NPRM or final rule that includes a Federal mandate that
may result in the expenditure by State, local, and Tribal governments,
or by the private sector of $100 million or more in 1996 dollars in any
given year, the agency must prepare, amongst other things, a written
statement that qualitatively and quantitatively assesses the costs and
benefits of the Federal mandate.
    As explained in the PRIA, this proposed rulemaking does not impose
unfunded mandates under the UMRA. It does not result in costs of $100
million or more in 1996 dollars to either State, local, or Tribal
governments, or to the private sector, in any one year. A copy of the
PRIA is available for review in the docket.

I. Environmental Assessment

    The National Environmental Policy Act of 1969 (NEPA; 42 U.S.C. 4321
et seq.), requires that Federal agencies analyze proposed actions to
determine whether the action would have a significant impact on the
human environment. The Council on Environmental Quality implementing
regulations (40 CFR parts 1500-1508) require Federal agencies to
conduct an environmental review considering (1) the need for the
action, (2) alternatives to the action, (3) probable environmental
impacts of the action and alternatives, and (4) the agencies and
persons consulted during the consideration process. DOT Order 5610.1C
(``Procedures for Considering Environmental Impacts'') establishes
departmental procedures for evaluation of environmental impacts under
NEPA and its implementing regulations.

1. Purpose and Need
    This NPRM would amend the HMR to maintain alignment with
international consensus standards by incorporating into the HMR various
amendments, including changes to proper shipping names, hazard classes,
packing groups, special provisions, packaging authorizations, air
transport quantity limitations, and vessel stowage requirements. PHMSA
notes that the amendments proposed in this NPRM are intended to result
in cost savings and reduced regulatory burden for shippers engaged in
domestic and international commerce, including trans-border shipments
within North America. Absent adoption of the amendments proposed in the
NPRM, U.S. companies--including numerous small entities competing in
foreign markets--may be at an economic disadvantage because of their
need to comply with a dual system of regulations. Further, among the
HMR amendments introduced in this rulemaking are those facilitating the
transportation of critical vaccines and other medical materials
associated with response to the COVID-19 public health emergency, and
others aligning HMR requirements with anticipated increases in the
volume of lithium batteries transported in interstate commerce from
electrification of the transportation and other economic sectors.
    As explained at greater length above in the preamble of this NPRM
and in the PRIA (each of which are incorporated by reference in this
discussion of the environmental impacts of the Proposed Action
Alternative), PHMSA expects the adoption of the regulatory amendments
proposed in this NPRM would maintain the high safety standard currently
achieved under the HMR. PHMSA has evaluated the safety each of the
amendments proposed in this NPRM on its own merit, as well as the
aggregate impact on transportation safety from adoption of those
amendments.
2. Alternatives
    In proposing this rulemaking, PHMSA is considering the following
alternatives:
No Action Alternative
    If PHMSA were to select the No Action Alternative, current
regulations would remain in place and no provisions would be amended or
added.
Proposed Action Alternative
    This alternative is the current proposal as it appears in this
NPRM, applying to transport of hazardous materials by various transport
modes (highway, rail, vessel and aircraft). The proposed amendments
included in this alternative are more fully discussed in the preamble
and regulatory text sections of this NPRM.
3. Reasonably Foreseeable Environmental Impacts of the Alternatives
No Action Alternative
    If PHMSA were to select the No Action Alternative, the HMR would
remain unchanged and no provisions would be amended or added. However,
any economic benefits gained through harmonization of the HMR with
updated international consensus standards (including, but not limited
to, the 21st revised edition of the UN Model Regulations, the 2021-2022
ICAO Technical Instructions and amendment 40-20 of the IMDG Code)
governing shipping of hazardous materials would not be realized.
    Additionally, the No Action Alternative would not adopt enhanced
and clarified regulatory requirements expected to maintain the high
level of safety in transportation of hazardous materials provided by
the HMR. As explained in the preamble to the NPRM, consistency between
the HMR and current international standards can enhance safety by (1)
ensuring that the HMR is informed by the latest best practices and
lessons learned; (2) improving understanding of and compliance with
pertinent requirements; (3) enabling consistent emergency response
procedures in the event of a hazardous materials incident; and (4)
facilitating the smooth flow of hazardous materials from their points
of origin to their points of destination, thereby avoiding risks to the
public and the environment from release of hazardous materials from
delays or interruptions in the transportation of those materials. PHMSA
would not capture those benefits if it were to pass on incorporating
updated international standards into the HMR under the No Action
Alternative.
    Additionally, some of the proposed HMR amendments are expected to
better accommodate than the current HMR the safe transportation of
emerging technologies (in particular lithium battery technologies), and
facilitate safe shipment of vaccines and other hazardous materials
associated with efforts to combat the COVID-19 public health emergency.
As explained in the PRIA, PHMSA expects a significant increase in the
volume of shipments of lithium batteries over time as more sectors of
the U.S. domestic and international economies electrify; PHMSA's
proposed HMR amendments pertaining to lithium batteries (which touch on
multiple stages in the lifecycle of a lithium battery) are intended to
ensure that expansion occurs safely. Similarly, PHMSA understands that
the response to the COVID-19 public health emergency will result in
sustained demand for shipments of refrigerated packages employing data
loggers transporting vaccines, as well as increased volumes of
sanitizing chemicals and medical waste from diagnosis, treatment, and
sanitization efforts; the HMR amendments within the Proposed Action
Alternative are intended to address the risks associated with those
COVID-related changes in transportation demand. The No Action
Alternative, in contrast, would not amend the HMR to account for these
emerging trends in demand for transportation of hazardous materials.
    PHMSA notes that the No Action Alternative would avoid any risks to
public safety and the environment from the NPRM's proposed
authorization of shipments of hazardous materials offered pursuant to
temporary certificates issued by Transport Canada. While the
transportation of hazardous materials always entails risk, allowing the
transportation of hazardous materials pursuant to temporary
certificates issued by Transport Canada could facilitate shipments of
hazardous materials that are not otherwise compliant with the HMR and
do not meet an equivalent standard of safety. Arguably, this allowance
could entail greater risks to public safety and the environment.
However, based on years of collaboration, PHMSA considers Transport
Canada to be a partner in hazardous materials safety and has confidence
in the technical expertise and judgement of the hazardous materials
safety SMEs at Transport Canada. PHMSA further submits that any risks
are mitigated by (1) the technical review by Transport Canada subject
matter experts to determine any shipments would be in the public
interest, (2) the limited duration of those temporary certificates, (3)
the terms and conditions imposed in those certificates, (4) other
regulatory requirements under the TDG Regulations or the HMR that may
remain applicable, and (5) PHMSA's limitation of its recognition of
temporary certificates to transportation via motor carrier and rail
during the particular shipment authorized by a temporary certificate.
    PHMSA expects that the No Action Alternative could have a modest
impact on GHG emissions. Because PHMSA expects the differences between
the HMR and international standards for transportation of hazardous
materials

could result in transportation delays or interruptions, PHMSA
anticipates that there could be modestly higher GHG emissions from some
combination of (1) transfer of delayed hazardous materials to and from
interim storage, (2) return of improperly shipped materials to their
point of origin, and (3) re-shipment of returned materials. PHMSA notes
that it is unable to quantify such GHG emissions because of the
difficulty in identifying the precise quantity or characteristics of
such interim storage or returns/re-shipments. The less demanding
holding time documentation requirements for refrigerated hazardous
gasses under the current HMR could also result in more frequent venting
of GHGs (including nitrous oxide, a potent GHG) from portable tanks
during delays in transportation. PHMSA also submits that, as explained
at greater length in Section IV.J., to the extent that there are any
delays arising from inconsistencies between the HMR and recently
updated international standards, there could also be adverse impacts
from the No Action Alternative for minority populations, low-income
populations, or other underserved and other disadvantaged communities.
Proposed Action Alternative
    As explained further in the discussions in each of the No Action
Alternative above, the preamble, and the PRIA, PHMSA anticipates the
changes proposed under the Proposed Action Alternative will maintain
the high safety standards currently achieved under the HMR.
Harmonization of the HMR with updated international consensus standards
is also expected to capture economic efficiencies gained from avoiding
shipping delays and compliance costs associated with having to comply
with divergent U.S. and international regulatory regimes for
transportation of hazardous materials. Further, PHMSA expects revision
of the HMR as proposed in the NPRM will accommodate safe transportation
of emerging technologies (in particular lithium battery technologies),
and facilitate safe shipment of vaccines and other hazardous materials
critical in efforts to combat the COVID-19 public health emergency.
    PHMSA acknowledges that the Proposed Action Alternative could
introduce risks to public safety and the environment from authorization
of shipments of hazardous materials pursuant to temporary certificates
issued by Transport Canada. As explained in the above discussion of the
No Action Alternative, PHMSA understands that risk to be largely
theoretical; PHMSA is unaware of evidence that hazardous material
incidents have occurred as a result of or under the authority of
temporary certificates. Further, PHMSA notes that the suite of other
factors (including Transport Canada's review process, certificate terms
and conditions, and otherwise applicable regulatory requirements of the
TDG Regulations and the HMR) would mitigate residual risks to public
safety and the environment.
    PHMSA expects that Proposed Action Alternative could realize modest
reductions in GHG emissions. Because PHMSA expects the differences
between the HMR and international standards for transportation of
hazardous materials could result in delays or interruptions, PHMSA
anticipates that the No Action Alternative could result in modestly
higher GHG emissions from some combination of (1) transfer of delayed
hazardous materials to and from interim storage, (2) return of
improperly shipped materials to their point of origin, or (3) re-
shipment of returned materials. The Proposed Action Alternative avoids
those risks resulting from divergence of the HMR from updated
international standards. PHMSA notes, however, that it is unable to
quantify any GHG emissions benefits because of the difficulty in
identifying the precise quantity or characteristics of such interim
storage or returns/re-shipments. PHMSA also noted that the less
demanding holding time documentation requirements for refrigerated
hazardous gasses under the current HMR could also result in more
frequent venting of GHGs (including nitrous oxide, a potent GHG) from
portable tanks during delays in transportation than would occur under
the Proposed Action Alternative. Lastly, PHMSA also submits that, as
explained at greater length in Section IV.J., the Proposed Action
Alternative would avoid any delayed or interrupted shipments arising
from the divergence of the HMR from updated international standards
under the No Action Alternative that could result in adverse impacts
for minority populations, low-income populations, or other underserved
and other disadvantaged communities.
4. Agencies Consulted
    PHMSA has coordinated with the Federal Aviation Administration, the
Federal Motor Carrier Safety Administration, the Federal Railroad
Administration, and the U.S. Coast Guard in the development of this
proposed rule. PHMSA solicits, and will consider, comments on the
NPRM's potential impacts on the human environment submitted by members
of the public, state and local governments, tribal communities and
industry.
5. Proposed Finding of No Significant Impact
    PHMSA expects the adoption of the Proposed Action Alternative's
regulatory amendments will maintain the HMR's current high level of
safety for shipments of hazardous materials transported by highway,
rail, aircraft, and vessel, and as such finds the HMR amendments in the
NPRM would have no significant impact on the human environment. PHMSA
expects that the Proposed Action Alternative will avoid adverse safety,
environmental justice, and GHG emissions impacts of the No Action
Alternative. Furthermore, based on PHMSA's analysis of these provisions
described above, PHMSA proposes to find that codification and
implementation of this rule would not result in a significant impact to
the human environment.
    PHMSA welcomes any views, data, or information related to
environmental impacts that may result from NPRM's proposed
requirements, the No Action Alternative, and other viable alternatives
and their environmental impacts.

J. Environmental Justice

    DOT Order 5610.2C (Department of Transportation Actions to Address
Environmental Justice in Minority Populations and Low-Income
Populations'') and Executive Orders 12898 (``Federal Actions to Address
Environmental Justice in Minority Populations and Low-Income
Populations''),\39\ 13985 (``Advancing Racial Equity and Support for
Underserved Communities Through the Federal Government''),\40\ 13990
(``Protecting Public Health and the Environment and Restoring Science
To Tackle the Climate Crisis''),\41\ and 14008 (``Tackling the Climate
Crisis at Home and Abroad'') \42\ require DOT agencies to achieve
environmental justice as part of their mission by identifying and
addressing, as appropriate, disproportionately high and adverse human
health or environmental effects, including interrelated social and
economic effects of their programs, policies, and activities on
minority populations, low-income populations, and other underserved and
disadvantaged communities.
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    \39\ 59 FR 7629 (Feb. 11, 1994).
    \40\ 86 FR 7009 (Jan. 20, 2021).
    \41\ 86 FR 7037 (Jan. 20, 2021).
    \42\ 86 FR 7619 (Feb. 1, 2021).

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    PHMSA has evaluated this proposed rule under the above Executive
Orders and DOT Order 5610.2C. PHMSA does not expect the proposed rule,
if finalized, to cause disproportionately high and adverse human health
and environmental effects on minority, low-income, underserved, and
other disadvantaged populations and communities. The rulemaking is
facially neutral and national in scope; it is neither directed toward a
particular population, region, or community, nor is it expected to
adversely impact any particular population, region, or community. And
because PHMSA expects the rulemaking would not adversely affect the
safe transportation of hazardous materials generally, PHMSA does not
expect the proposed revisions would entail disproportionately high
adverse risks for minority populations, low-income populations, or
other underserved and other disadvantaged communities.
    PHMSA submits that the proposed rulemaking could in fact reduce
risks to minority populations, low-income populations, or other
underserved and other disadvantaged communities. Because the proposed
HMR amendments could avoid the release of hazardous materials and
reduce the frequency of delays and returned/resubmitted shipments of
hazardous materials resulting from conflict between the current HMR and
updated international standards, the proposed rule could reduce risks
to populations and communities--including any minority, low-income,
underserved and other disadvantaged populations and communities--in the