[Federal Register Volume 71, Number 167 (Tuesday, August 29, 2006)]
[Rules and Regulations]
[Pages 51122-51129]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: E6-14255]



[[Page 51122]]

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DEPARTMENT OF TRANSPORTATION

Pipeline and Hazardous Materials Safety Administration

49 CFR Parts 173 and 180

[Docket No. PHMSA-03-14405 (HM-220F)]
RIN 2137-AD78


Hazardous Materials: Aluminum Cylinders Manufactured of Aluminum 
Alloy 6351-T6 Used in SCUBA, SCBA, and Oxygen Services--Revised 
Requalification and Use Criteria

AGENCY: Pipeline and Hazardous Materials Safety Administration (PHMSA), 
DOT.

ACTION: Final rule.

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SUMMARY: This final rule revises the Hazardous Materials Regulations to 
address a known safety problem with cylinders manufactured of aluminum 
alloy 6351-T6. The revisions include an inspection and testing program 
for early detection of sustained load cracking on cylinders 
manufactured of aluminum alloy 6351-T6 and used in self-contained 
underwater breathing apparatus (SCUBA), self-contained breathing 
apparatus (SCBA), and oxygen services.

DATES: Effective date: January 1, 2007.

FOR FURTHER INFORMATION CONTACT: Mark Toughiry, Office of Hazardous 
Materials Technology, (202) 366-4545, or Kurt C. Eichenlaub, Office of 
Hazardous Materials Standards, (202) 366-8553; PHMSA, U.S. Department 
of Transportation, 400 Seventh Street, SW., Washington, DC 20590-0001.

SUPPLEMENTARY INFORMATION:

Contents

I. Background
II. Analysis of Comments to SNPRM
III. Section-by-Section Review
IV. Regulatory Analyses and Notices
    A. Statutory/Legal Authority for This Rulemaking
    B. Executive Order 12866 and DOT Regulatory Polices and 
Procedures
    C. Executive Order 13132
    D. Executive Order 13175
    E. Regulatory Flexibility Act, Executive Order 13272, and DOT 
Procedures and Policies
    F. Paperwork Reduction Act
    G. Regulation Identifier Number (RIN)
    H. Unfunded Mandates Reform Act
    I. Environmental Assessment
    J. Privacy Act

I. Background

    Cylinders made of aluminum alloy 6351-T6 are known to be 
susceptible to sustained load cracking (SLC) in the neck and shoulder 
area of the cylinder. While the exact cause and mechanism of SLC are 
not yet fully understood, it appears the cracks primarily originate 
from the bottom of the neck of the cylinder, at or below the lowest 
thread position in the interior of the cylinder. The cracking was first 
brought to PHMSA's attention by persons retesting cylinders under the 
periodic retest procedures of Sec.  180.209 of the Hazardous Materials 
Regulations (HMR; 49 CFR parts 171-180). The majority of SLC-related 
ruptures have occurred in self-contained underwater breathing apparatus 
(SCUBA), self-contained breathing apparatus (SCBA), and oxygen 
services. Since 1994, the Pipeline and Hazardous Materials Safety 
Administration (PHMSA, we) has been notified of thirteen suspected SLC 
ruptures of cylinders manufactured of aluminum alloy 6351-T6. Five of 
the thirteen ruptures resulted in serious injuries. Data from 
manufacturers show there are thousands of cylinders with small, non-
leaking cracks, which are regularly detected during a diligent, 
detailed requalification process. Manufacturers of cylinders made from 
the 6351-T6 aluminum alloy have conducted research, testing, and 
analysis to determine whether there is any correlation between SLC and 
the probability of a cylinder rupture. The data indicate the cylinders 
may leak but not rupture when operated at marked service pressure. The 
data also indicate the probability of cracking increases with an 
increase in stress levels.
    We performed additional metallurgical analysis on several ruptured 
cylinders to verify the cause of failure and failure mode. (See the 
metallurgical analysis reports at http://hazmat.dot.gov/pubs/reports/cylinder/3al_cyls_info.htm). Those metallurgical analyses revealed 
SLC caused the cylinder ruptures, but the results were inconclusive as 
to why the cylinders abruptly ruptured instead of developing leaks. 
North American manufacturers discontinued using aluminum alloy 6351-T6 
prior to 1990, replacing it with aluminum alloy 6061-T6, which is not 
susceptible to SLC. Cylinders manufactured of aluminum alloy 6351-T6 
prior to 1990 include seamless aluminum cylinders marked ``DOT 3AL;'' 
and those marked with one of the following exemption or special permit 
numbers: 6498, 7042, 8107, 8364, and 8422. We estimate approximately 
3.7 million U.S. cylinders manufactured from aluminum alloy 6351-T6 are 
currently in use in SCUBA, SCBA, and oxygen services.
    On August 8, 2002, we published a final rule (67 FR 51626) amending 
the requirements of the HMR applicable to the maintenance, 
requalification, repair, and use of DOT specification cylinders. On May 
8, 2003, we issued a subsequent final rule (68 FR 24653) making further 
revisions in response to appeals. In these final rules, we added the 
following amendments pertaining to DOT specification cylinders made 
with aluminum alloy 6351-T6:
     Removed the authorization for the manufacture of DOT 
specification cylinders made with aluminum alloy 6351-T6 because 
cylinders manufactured with this aluminum alloy have a greater risk of 
failure than other aluminum cylinders.
     Prohibited the use of cylinders made with aluminum alloy 
6351-T6 for the transportation of materials poisonous by inhalation in 
Hazard Zone A effective on October 1, 2002. After that date, cylinders 
made of aluminum alloy 6351-T6 may not be filled and offered for 
transportation in toxic inhalation hazard service.
     Prohibited the use of cylinders manufactured of aluminum 
alloy 6351-T6 for gases having pyrophoric properties.
     Required a visual inspection of DOT specification or 
exemption cylinders made of aluminum alloy 6351-T6 for evidence of SLC 
in the neck and shoulder area.
    On September 10, 2003, the Research and Special Programs 
Administration, the predecessor agency to PHMSA, published an NPRM (68 
FR 53314) proposing to amend HMR requirements applicable to aluminum 
cylinders manufactured using aluminum alloy 6351-T6. In the NPRM, for 
cylinders manufactured of aluminum alloy 6351-T6 used in SCUBA, SCBA, 
and oxygen service, we proposed the following amendments:
     A combined visual and eddy current examination at the time 
of requalification.
     A new Appendix C to Part 180, to specify the procedure to 
conduct the eddy current examination.
     Suitable safeguards to protect personnel and facilities 
should a cylinder fail during the filling process.
    Although we believe the thirteen reported SLC ruptures under 
represent the extent of the SLC issue, we did not have sufficient data 
to determine whether the SLC-related ruptures extend beyond those 
services discussed above. Therefore, in the NPRM we requested 
additional information from manufacturers and users who were aware of a 
cylinder rupture, whether domestic or foreign, involving a DOT 3AL 
cylinder or any other cylinder manufactured from aluminum alloy 6351-
T6. More broadly, we invited commenters to address the issue of

[[Page 51123]]

whether the new inspection requirements proposed in the NPRM should 
apply to cylinders manufactured of aluminum alloy 6351-T6 and used in 
services other than SCUBA, SCBA, or oxygen.
    On October 26, 2005, based on comments received in response to the 
NPRM, we published an SNPRM (70 FR 61762) to revise the amendments 
originally proposed in the NPRM, expand the scope of the rulemaking, 
and propose additional requirements for DOT 3AL cylinders manufactured 
of aluminum alloy 6351-T6. In the SNPRM, we proposed to:
     Require a combined visual and eddy current examination at 
the time of requalification of DOT 3AL cylinders manufactured of 
aluminum alloy 6351-T6 and used in carbon dioxide service, in addition 
to those used in SCUBA, SCBA, and oxygen services.
     Impose a 40-year service life for cylinders manufactured 
of aluminum alloy 6351-T6 and used in SCUBA, SCBA, oxygen and carbon 
dioxide services.
     Add additional training requirements for persons 
performing the eddy current examination combined with a visual 
inspection.
     Modify procedures and recordkeeping requirements for eddy 
current examinations.
     Add a requirement to perform the initial eddy current 
examination combined with visual inspection for DOT 3AL cylinders 
manufactured of aluminum alloy 6351-T6 within three years of 
publication of a final rule in the Federal Register.

II. Analysis of Comments

    We received 10 comments from individuals and organizations, 
including cylinder manufacturers, representatives of the SCUBA and 
compressed gas industries, and eddy current test equipment 
manufacturers. The following companies, organizations, and individuals 
submitted comments: George Perez (Perez; RSPA-2003-14405-17); Matheson 
Tri Gas (Matheson; RSPA-2003-14405-18); Air Liquide Canada, Inc. (Air 
Liquide; RSPA-2003-14405-19); Engineered Inspection Systems (Engineered 
Inspection; RSPA-2003-14405-20); Western Sales & Testing of Deer Park, 
Inc. (Western Sales; RSPA-2003-14405-21, RSPA-2003-14405-22, RSPA-2003-
14405-23, RSPA-2003-14405-24); Barlen and Associates, Inc. (Barlen; 
RSPA-2003-14405-25); Luxfer Gas Cylinders (Luxfer; RSPA-2003-14405-26); 
Brian H. Schumann (Schumann; RSPA-2003-14405-27); Compressed Gas 
Association (CGA; RSPA-2003-14405-28); and, Amy Morgan Bruecks 
(Bruecks; RSPA-2003-14405-29). These comments are available in their 
entirety at the U.S. DOT Docket Management System Web site: http://dms.dot.gov, under Docket No. PHMSA-03-14405.
    In this final rule, we summarize comments submitted to the docket, 
address concerns raised by commenters, and discuss our decisions on 
specific issues.

A. Carbon Dioxide Service

    The SNPRM proposed enhanced requalification requirements and a 40-
year service life for DOT 3AL cylinders manufactured of aluminum alloy 
6351-T6 and used in SCUBA, SCBA, oxygen, and carbon dioxide services. 
DOT 3AL cylinders used for carbon dioxide service were not included in 
the original NPRM, but were added to the SNPRM as a result of our own 
initiative and in response to comments submitted to the NPRM. Comments 
to the SNPRM are divided on the proposed scope of the rule. Several 
commenters [Bruecks; Engineered Inspection; Western Sales] recommend 
expanding the scope of the final rule to include ``all cylinders 
manufactured of aluminum alloy 6351-T6'' while others [CGA; Barlen] are 
opposed to expanding the scope beyond cylinders used in SCUBA, SCBA, 
and oxygen services.
    Three commenters [Bruecks; Engineered Inspection; Western Sales] 
assert cylinders manufactured with aluminum alloy 6351-T6 are dangerous 
regardless of end use. One commenter [Western Sales] states, ``[T]o 
simplify, and because I believe that this cylinder is just as dangerous 
when being used in services not addressed, I believe that any reference 
to just the 4 specific services be dropped. While I appreciate that 
there are no catastrophic failures from other user groups, that have 
been reported, I believe including all cylinders made of 6351-T6 is in 
the best interest of the cylinder industry and the general public.'' 
Each of the three commenters recommends amending proposed requirements 
to include ``all'' cylinders manufactured of aluminum alloy 6351-T6 in 
the scope of this rule.
    We disagree. As previously stated, the majority of cylinder 
ruptures due to SLC have occurred in SCUBA, SCBA, and oxygen services. 
We believe these ruptures are directly related to the increased 
frequencies with which these cylinders are filled and their higher 
operating pressures. As discussed in the NPRM (68 FR 53314), the 
probability of SLC increases the more frequently the cylinder is 
filled. Additionally, cylinders used in SCUBA and SCBA services may be 
used by a diver or firefighter, substantially increasing the risk of 
injury or fatality in the event of a cylinder rupture. To date, there 
have been no reported ruptures involving DOT 3AL cylinders manufactured 
of aluminum alloy 6351-T6 and used in carbon dioxide, fire 
extinguisher, or other industrial gas service. Therefore, we are not 
expanding the scope of the rule to include all DOT 3AL cylinders 
manufactured of aluminum alloy 6351-T6.
    Two commenters [CGA; Barlen] to the SNPRM oppose expanding the 
scope of the rule to include cylinders used in carbon dioxide service. 
One commenter [CGA] states, ``SLC is most likely to occur at high 
pressures. Because cylinders used in [carbon dioxide] service are 
operated at a lower pressure than those used in SCBA and SCUBA service, 
the rate of cracking for cylinders in [carbon dioxide] service will be 
substantially less than for those used in SCBA and SCUBA service. 
Failure by SLC is not expected to occur in cylinders used in [carbon 
dioxide] service.''
    A comment submitted by City Carbonic Sales Service [City Carbonic; 
RSPA-2003-14405-13] to the 2003 NPRM (68 FR 53314) asserts a 
significant number of cylinders used in carbon dioxide service were 
condemned due to SLC during a three-year in-house survey. However, a 
commenter [CGA] to the SNPRM disagrees with that assertion, suggesting 
it was unsubstantiated. The commenter [CGA] states the specific type of 
cracks observed in the condemned cylinders were not confirmed to be 
related to SLC, but were most likely due to the over-torquing of these 
cylinder's taper threaded valves causing cracks to occur in the neck of 
the cylinder. Two commenters [CGA; Barlen] suggest we are proposing to 
expand the scope of the rule without providing appropriate technical 
data to justify such an amendment. These commenters also assert SLC is 
not likely to develop in DOT 3AL cylinders used in carbon dioxide 
service and recommend we remove the proposed amendment to include these 
cylinders in the scope of this rule.
    We agree. Therefore, in this final rule, we are removing the 
proposal expanding the scope of the rulemaking to include cylinders 
manufactured of aluminum alloy 6351-T6 and used in carbon dioxide 
service. We agree with the commenter's [CGA] statement that cylinders 
used in carbon dioxide service generally operate at lower pressures 
and, thus, have a reduced likelihood of developing SLC. Commenters are 
correct there have been no reported

[[Page 51124]]

cylinder ruptures involving DOT 3AL cylinders manufactured of aluminum 
alloy 6351-T6 and used in carbon dioxide, fire extinguisher, or other 
industrial gas services. However, we will continue to monitor these 
cylinders for evidence of SLC and, if the situation warrants, we may 
revisit this issue in a future rulemaking.

B. 40-Year Service Life

    Currently, cylinders manufactured of aluminum alloy 6351-T6 may be 
used indefinitely so long as they conform to the requalification test 
and inspection criteria established in the HMR. The SNPRM proposed a 
40-year service life from the date of manufacture for DOT 3AL cylinders 
manufactured of aluminum alloy 6351-T6 and used in SCUBA, SCBA, oxygen, 
and carbon dioxide services. Several commenters [CGA; Air Liquide; 
Barlen] to the SNPRM oppose the 40-year service life proposed for DOT 
3AL cylinders manufactured of aluminum alloy 6351-T6. These commenters 
suggest there is no evidence these cylinders are more likely to be 
susceptible to SLC as they age and state the proposed amendment lacks 
the appropriate test data, analysis, or statistical data to support the 
implication that older cylinders are more likely to develop SLC. These 
commenters further suggest requalification is the most appropriate 
method to identify and condemn DOT specification cylinders regardless 
of their age.
    After consideration of these comments, we agree our proposed 40-
year service life for cylinders manufactured of aluminum alloy 6451-T6 
and used in SCUBA, SCBA, carbon dioxide, and oxygen services is not 
warranted at this time. We also agree with the commenters' [CGA; Air 
Liquide; Barlen] statements that the requalification process is an 
effective method of condemning deteriorated or damaged DOT 
specification cylinders. Further, there is evidence these cylinders are 
being voluntarily removed from service as defects are identified 
through inspections and testing. Therefore, we are not adopting the 40-
year service life in this final rule. We will continue to monitor 
cylinders manufactured of aluminum alloy 6351-T6 for evidence of SLC. 
If the situation warrants, we may revisit this issue in a future 
rulemaking.

C. Requalification Schedule for Eddy Current Examinations

    Currently, the HMR specify periodic requalification requirements 
for DOT 3AL cylinders. Periodic requalification includes a volumetric 
expansion test and visual examination at least once every five years. 
In the SNPRM, we proposed to require an initial eddy current 
examination to be performed within three years of the effective date of 
this final rule, and every 5 years thereafter. Commenters generally 
support the proposed eddy current examination for cylinders used in 
SCUBA, SCBA, oxygen and carbon dioxide services. However, several 
commenters [CGA; Barlen; Matheson; Engineered Inspection; Western 
Sales; Bruecks] assert the requirement to perform the initial eddy 
current examination within three years of the effective date of this 
final rule is unnecessary and may be difficult to comply with. These 
commenters point out requiring the eddy current examination within 
three years of the effective date may result in a large number of 
cylinders pulled from service for requalification twice within a five 
year period; once for the eddy current examination and once for the 
scheduled periodic requalification. Several commenters [Engineered 
Inspection; Western Sales; Bruecks] also assert the eddy current 
marking could cause confusion because it is required to be marked in 
association with the test date of the last volumetric expansion test, 
which could be different from the date of the eddy current examination. 
Additionally, one commenter [Matheson] is concerned the few companies 
currently equipped to conduct eddy current examinations may become 
overloaded with additional test work, resulting in backlogs and test 
delays. To alleviate confusion and reduce the overall burden, these 
commenters suggest revising the amendment to require eddy current 
examinations at the time of a cylinder's next scheduled periodic 
requalification, which is required every five years.
    We agree. In this final rule, we are removing the proposal to 
perform an eddy current examination within three years of the effective 
date of this rule, and we are requiring an eddy current examination to 
be conducted at the cylinder's next required periodic requalification 
after January 1, 2007, the effective date of this final rule. As a 
result, the date stamp on each cylinder will accurately reflect the 
date of the last periodic requalification, including the eddy current 
and visual examination.

D. Appendix C to Part 180

    In the SNPRM, we proposed to add a new Appendix C to part 180 to 
specify procedures, training, and recordkeeping requirements for 
performing the eddy current examination and visual inspection of 
cylinders manufactured of aluminum alloy 6351-T6 and used in SCBA, 
SCUBA, oxygen and carbon dioxide services. Two commenters [CGA; 
Engineered Inspection] oppose the requirement to include the location 
and type of defect on the test report. These commenters assert this 
information is not necessary and increases the time required to 
document each examination. One commenter [Engineered Inspection] 
states, ``details of this nature take much more time to note, and this 
will increase the amount of time required to perform a test. The end 
result will be an increased cost to the customer.'' Both commenters 
recommend removing this requirement since the pass/fail entry on the 
report is sufficient to indicate whether a defect was detected during 
the examination.
    We agree. Since the eddy current with visual examination is 
conducted to locate SLC in the neck and shoulder of a cylinder, a pass/
fail indication on the test report is sufficient for indicating whether 
a defect was found during the examination. Therefore, we are removing 
the proposal to notate the location and type of defect found on the 
test report.
    One commenter [Western Sales] opposes the use of the term 
``rejected'' in Appendix C to part 180 to describe cylinders failing 
the eddy current with visual examination. The commenter asserts the 
term ``rejected'' implies the cylinder can be repaired and returned to 
service. The commenter recommends removing the term ``rejection'' and 
replacing it with ``condemned'' to ensure the cylinder is not returned 
to service.
    We agree. The terms ``rejection criteria,'' and ``rejected'' in 
Appendix C to part 180 were intended to indicate cylinders failing the 
eddy current combined with visual examination must be permanently 
removed from service. We did not intend to allow those cylinders to be 
reconditioned or reused under any circumstances. The commenter is 
correct the term is inconsistent with Sec.  180.205(i), which uses the 
terms ``cylinder condemnation,'' and ``condemned'' to describe 
cylinders to be permanently removed from service. In this final rule, 
we are revising the terminology used in Appendix C to part 180 to be 
consistent with established requalification requirements.
    A commenter [Western Sales] also points out the owners name and 
symbol may not be present (i.e. stamped on the cylinder). For this 
reason, the commenter recommends revising the language requiring a 
notation of the

[[Page 51125]]

cylinder owner's name or symbol to include the words ``if present.''
    We agree. It is not necessary to record the owner's name or symbol 
if it is not present or available at the time of requalification. 
Therefore, in this final rule, we are revising the language to require 
requalification records to include the cylinder owner's name or symbol, 
if present. This revision is consistent with established cylinder 
requalification recordkeeping requirements.
    One commenter [Western Sales] states the serial number must be 
included in the test report to readily identify the examined cylinder. 
We agree. We inadvertently omitted the cylinder serial number as a 
required notation on the test report. We are adding the serial number 
as information required to be included on the test report to identify 
cylinders that have been examined and tested.
    In addition, we are revising the training requirements for persons 
who perform eddy current examinations to require an employer to certify 
they have been trained and tested in accordance with their company's 
specific eddy current and visual examination procedures. We are 
removing references to specific training criteria. It is the employer's 
responsibility to ensure each employee is properly trained in the 
functions he or she performs. The training requirements are consistent 
with those specified in Sec.  172.704. Therefore, it is not necessary 
to list specific training criteria for persons who perform eddy current 
examinations.
    Further, we are removing language from Appendix C to part 180, 
which required the visual examination to be conducted before and after 
the eddy current examination. After further review, we believe it is 
only necessary to conduct one visual inspection either before or after 
the eddy current examination. Cylinder requalifiers performing the 
visual examination prior to the eddy current examination may conduct a 
second visual examination afterwards to confirm the results of the eddy 
current examination, however, a second visual examination is not 
required.

E. Operational Controls

    In the SNPRM, we proposed to add to the HMR operational controls as 
recommended safety practices for filling DOT 3AL cylinders manufactured 
of aluminum alloy 6351-T6. Two commenters [Barlen; Western Sales] 
oppose the proposed operational controls in the SNPRM. One commenter 
[Barlen] suggests it is inappropriate to require operational controls 
to be in place during the filling process unless we intend to provide 
specific instructions on ``how to fill'' an aluminum alloy cylinder. 
Another commenter [Western Sales] suggests liability issues could arise 
from the proposed requirement for only one person to be around a 
cylinder during the filling operation.
    We disagree. The operational controls proposed in the SNPRM are 
recommendations intended to emphasize persons filling DOT 3AL cylinders 
manufactured of aluminum alloy 6351-T6 should take additional safety 
precautions because of the risk of rupture during the filling process. 
The majority of cylinder ruptures due to SLC have occurred during the 
filling process. We do not believe the operational controls create 
potential liability issues because they are recommendations rather than 
mandatory requirements.

III. Section-by-Section Review

Part 173

Section 173.301
    This section establishes general requirements for the shipment of 
compressed gases in cylinders. Paragraph (d) of this section addresses 
the transportation of gases capable of combining chemically and 
prohibits the use of DOT 3AL cylinders for the transportation of 
pyrophoric gases. In this final rule, we are revising paragraph (d) to 
remove reference to DOT 3AL cylinders manufactured of aluminum alloy 
6351-T6. The prohibition is relocated to a new paragraph (o) titled 
``DOT 3AL cylinders made of aluminum alloy 6351-T6.''
Section 173.302
    This section addresses requirements for filling cylinders with non-
liquefied compressed gases. In this final rule, we are adding a new 
paragraph (e) to recommend operational controls during the filling 
process for cylinders manufactured of aluminum alloy 6351-T6 and used 
in SCUBA, SCBA, and oxygen services. The operational controls will 
reduce the risk of personal injury and property damage during the 
filling process.

Part 180

Section 180.205
    This section establishes general requirements for the 
requalification of cylinders used to transport hazardous materials. 
Paragraph (f) sets forth requirements for periodic visual inspections 
of cylinders. Paragraph (f)(4) specifically requires cylinders 
manufactured of aluminum alloy 6351-T6 to be inspected for evidence of 
SLC in the neck and shoulder areas. In this final rule, we are revising 
paragraph (f)(4) to reference part 180, Appendix C for requalification 
requirements for DOT 3AL cylinders manufactured of aluminum alloy 6351-
T6 and used in SCUBA, SCBA, and oxygen services.
Section 180.209
    This section establishes requirements for the requalification of 
DOT specification cylinders. Paragraph (a) of this section includes a 
table with the requalification criteria for DOT specification 
cylinders. In this final rule, we are amending the entry for the DOT 
3AL cylinder in the ``Requalification of Cylinders'' table to add a 
reference to new paragraph (m). New paragraph (m) requires cylinders 
manufactured of aluminum alloy 6351-T6 and used in SCUBA, SCBA, and 
oxygen services to undergo an eddy current and visual examination for 
early detection of SLC in the neck and shoulder area of the cylinder. 
We are adding a footnote (3) to specify the eddy current and visual 
examinations do not apply to cylinders used for carbon dioxide, fire 
extinguisher or other industrial gas services.
Section 180.213
    This section establishes marking requirements for cylinders passing 
periodic requalification testing. We are revising paragraph (d), which 
sets forth the specific markings required, and adding a new paragraph 
(f)(9) to specify the requalification marking requirements for aluminum 
cylinders successfully passing the combined eddy current examination 
and visual inspection.

Appendix C to Part 180

    In this final rule, we are adding a new Appendix C to part 180 to 
specify procedures, training, and recordkeeping requirements for 
performing the eddy current examination and visual inspection of 
cylinders manufactured of aluminum alloy 6351-T6 and used in SCUBA, 
SCBA, and oxygen services. The new appendix includes:
    (1) Eddy current and visual examination and inspection procedures 
to identify SLC;
    (2) Eddy current equipment specifications and record retention 
requirements;
    (3) Cylinder condemnation criteria;
    (4) Record retention requirements for examinations and inspections; 
and,
    (5) Training requirements for personnel who perform eddy current 
and visual examinations and inspections.

[[Page 51126]]

IV. Regulatory Analyses and Notices

A. Statutory/Legal Authority for This Rulemaking

    This final rule is published under authority of Federal hazardous 
materials transportation law (Federal hazmat law; 49 U.S.C. 5101 et 
seq.). Section 5103(b) of Federal hazmat law authorizes the Secretary 
of Transportation to prescribe regulations for the safe transportation, 
including security, of hazardous material in intrastate, interstate, 
and foreign commerce. To this end, as discussed in detail earlier in 
this preamble, the final rule proposes to revise current HMR 
requirements applicable to aluminum cylinders manufactured using 
aluminum alloy 6351-T6 and used in SCUBA, SCBA, and oxygen services. 
The purpose of the final rule is to adopt a standard for early 
detection of SLC to reduce the risk of a cylinder rupture and to 
establish a service life for cylinders manufactured of aluminum alloy 
6351-T6 and used in SCUBA, SCBA, and oxygen services.

B. Executive Order 12866 and DOT Regulatory Policies and Procedures

    This final rule is not considered a significant regulatory action 
under section 3(f) of Executive Order 12866 and, therefore, was not 
reviewed by the Office of Management and Budget. The final rule is not 
considered a significant rule under the Regulatory Policies and 
Procedures of the Department of Transportation [44 FR 11034].
    The compliance costs associated with this rule are minimal. The 
regulatory analysis indicates the increased cost for performing an 
additional non-destructive examination (NDE) and implementing 
operational controls is small compared to the cost and safety risks of 
doing nothing; it is significantly less than the cost of immediately 
removing all cylinders from service. We estimate the cost of the 
hydrostatic test and internal visual inspection required under the 
current regulation to be $5 per cylinder for each 5-year periodic 
requalification. We estimate the cost to conduct the additional visual 
inspection and eddy current testing required under this final rule 
combined with the current hydrostatic and visual inspection to be $7.25 
per cylinder for each periodic requalification. Therefore, we estimate 
the additional annual cost associated with this final rule to be $0.45 
per cylinder ($2.25 additional requalification costs/5-year 
requalification period). A number of cylinder owners and retesters are 
voluntarily utilizing NDE as part of the 5-year requalification testing 
process for these cylinders. We estimate about 1 million of the total 
population of 3.7 million cylinders are already subject to enhanced 
inspection and testing requirements because of voluntary actions by 
cylinder owners and retesters. Further, annual costs to industry will 
diminish with time as cylinders are condemned or voluntarily removed 
from service. Over the next five years, we expect the population of 
cylinders manufactured of aluminum alloy 6351-T6 to decrease by 
500,000, decreasing the number of cylinders not currently subject to 
voluntary NDE to 2.2 million.
    Based on the foregoing analysis, we estimate initial annual costs 
to comply with the test and inspection requirements of this final rule 
to be $1.215 million (2.7 million cylinders not currently subject to 
NDE x $.45 NDE test costs = $1.215 million). Over a 5-year period, 
compliance costs will decrease to $990,000 (2.2 million cylinders x 
$.45 NDE test costs). Thus, the total five year compliance cost to 
industry will be $4.22 million.
    The benefits of implementing the provisions of this final rule 
include avoided fatalities, injuries, and damages resulting from 
cylinder ruptures caused by SLC. The annual benefits associated with 
this final rule total $1,183,125, or $5.9 million over 5 years.
    The cost-benefit analysis is based on information obtained from 
cylinder manufacturers, industrial gas companies, cylinder inspectors, 
and metallurgical evaluation of the ruptured cylinders. A regulatory 
analysis is available for review in the docket.

C. Executive Order 13132

    This final rule has been analyzed in accordance with the principles 
and criteria contained in Executive Order 13132 (``Federalism''). This 
final rule preempts State, local and Indian tribe requirements, but 
does not adopt any regulation with 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. Therefore, the consultation and funding requirements of 
Executive Order 13132 do not apply.
    The Federal hazardous materials transportation law, 49 U.S.C. 5101 
et seq., contains an express preemption provision (49 U.S.C. 5125(b)) 
preempting State, local, and Indian tribe requirements on certain 
covered subjects. Covered subjects are:
    (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, manufacturing, fabricating, marking, maintenance, 
reconditioning, repairing, or testing of a packaging or container 
represented, marked, certified, or sold as qualified for use in 
transporting hazardous material.
    This final rule covers items 2 and 5 and would preempt any State, 
local, or Indian tribe requirements not meeting the ``substantively the 
same'' standard.
    Pursuant to Sec.  5125(b)(2) of the Federal hazmat law, if the 
Secretary of Transportation issues a regulation concerning any of the 
covered subjects, the Secretary must determine and publish in the 
Federal Register the effective date of Federal preemption. The 
effective date may not be earlier than the 90th day following the date 
of issuance of the final rule and not later than two years after the 
date of issuance. PHMSA has determined the effective date of Federal 
preemption for these requirements will be one year from the date of 
publication of a final rule in the Federal Register.

D. Executive Order 13175

    This final rule has been analyzed in accordance with the principles 
and criteria contained in Executive Order 13175 (``Consultation and 
Coordination with Indian Tribal Governments''). Because this final rule 
does not have tribal implications, does not impose substantial direct 
compliance costs, and is not required by statute, the funding and 
consultation requirements of Executive Order 13175 do not apply.

E. Regulatory Flexibility Act, Executive Order 13272, and DOT 
Regulatory Policies and Procedures

    The Regulatory Flexibility Act (5 U.S.C. 601 et seq.) requires an 
agency to review regulations to assess their impact on small entities 
unless the agency determines a rule is not expected to have a 
significant economic impact on a substantial number of small entities. 
This rule imposes only minimal new costs of compliance on the regulated 
industry. Based on the assessment in the regulatory evaluation, I 
hereby certify that while this rule applies to a substantial number of 
small entities, there will not be a significant economic impact on 
those small entities. A

[[Page 51127]]

detailed Regulatory Flexibility analysis is available for review in the 
docket.
    This final rule has been developed in accordance with Executive 
Order 13272 (``Proper Consideration of Small Entities in Agency 
Rulemaking'') and DOT's policies and procedures to promote compliance 
with the Regulatory Flexibility Act to ensure potential impacts of 
draft rules on small entities are properly considered.

F. Paperwork Reduction Act

    PHMSA currently has an approved information collection under OMB 
Control No. 2137-0022, Testing, Inspection, and Marking Requirements 
for Cylinders with 168,431 burden hours, and an expiration date of 
August 31, 2008. This final rule results in an increase in annual 
burden and costs based on a new information collection requirement. The 
amendments regarding the shipment of aluminum cylinders which resulted 
in a new information collection requirement were submitted to the 
Office of Management and Budget (OMB) for review and approval at the 
NPRM stage. At the request of OMB, we are re-submitting this new 
information collection burden request for final OMB approval at the 
final rule stage. Upon approval of this information collection by OMB, 
we will publish a separate notice in the Federal Register.
    PHMSA has developed burden estimates to reflect changes in this 
final rule. PHMSA estimates the total information collection and 
recordkeeping burden would be as follows:
    OMB No. 2137-0022:
    Total Annual Number of Responders: 103,779.
    Total Annual Responses: 168,879.
    Total Annual Burden Hours: 271,461.
    Total Annual Burden Cost: $2,614,396.
    Total One-Time Start-Up Cost: $964,000.
    Under the Paperwork Reduction Act of 1995, no person is required to 
respond to an information collection unless it has been approved by OMB 
and displays a valid OMB control number. Section 1320.8(d), Title 5, 
Code of Federal Regulations requires that PHMSA provide interested 
members of the public and affected agencies an opportunity to comment 
on information collection and recordkeeping requests. PHMSA 
specifically requested comments on the information collection and 
recordkeeping burdens associated with developing, implementing, and 
maintaining these requirements for approval under this final rule.
    Direct your requests for a copy of the information collection to 
Deborah Boothe or T. Glenn Foster, Office of Hazardous Materials 
Standards (PHH-10), Pipeline and Hazardous Materials Safety 
Administration (PHMSA), Room 8102, 400 Seventh Street, SW., Washington, 
DC 20590-0001, Telephone (202) 366-8553. In addition, you may submit 
comments specifically related to the information collection burden to 
the PHMSA Desk Officer, OMB, at fax number 202-395-6974.

G. Regulation Identifier Number (RIN)

    A regulation identifier number (RIN) is assigned to each regulatory 
action listed in the Unified Agenda of Federal Regulations. The 
Regulatory Information Service Center publishes the Unified Agenda in 
April and October of each year. The RIN number contained in the heading 
of this document can be used to cross-reference this action with the 
Unified Agenda.

H. Unfunded Mandates Reform Act

    This final rule does not impose unfunded mandates under the 
Unfunded Mandates Reform Act of 1995. It does not result in costs of 
$120.7 million or more to either State, local or tribal governments, in 
the aggregate, or to the private sector, and is the least burdensome 
alternative that achieves the objective of the rule.

I. Environmental Assessment

    The National Environmental Policy Act of 1969 (NEPA), as amended 
(42 U.S.C. 4321-4347), requires Federal agencies to consider the 
consequences of major federal actions and prepare a detailed statement 
on actions significantly affecting the quality of the human 
environment. There are no significant environmental impacts associated 
with this final rule. PHMSA is amending requirements in the HMR 
pertaining to DOT 3AL aluminum cylinders. The purpose of this 
rulemaking initiative is to minimize personal injury during the filling 
process and to adopt a standard for early detection of sustained load 
cracking of cylinders manufactured of aluminum alloy 6351-T6 in order 
to reduce the risk of a cylinder rupture. Adopting a standard for early 
detection of sustained load cracking in order to reduce the risk of a 
cylinder rupture has no potential for environmental damage or 
contamination.

J. Privacy Act

    Anyone is able to search the electronic form of all comments 
received into any of our dockets by the name of the individual 
submitting the comment (or signing the comment, if submitted on behalf 
of an association, business, labor union, etc.). You may review DOT's 
complete Privacy Act Statement in the Federal Register published on 
April 11, 2000 (Volume 65, Number 70; Pages 19477-78) or you may visit 
http://dms.dot.gov.

List of Subjects

49 CFR Part 173

    Hazardous materials transportation, Incorporation by reference, 
Packaging and containers, Radioactive materials, Reporting and 
recordkeeping requirements, Uranium.

49 CFR Part 180

    Hazardous materials transportation, Incorporation by reference, 
Motor vehicle safety, Packaging and containers, Reporting and 
recordkeeping requirements.

0
In consideration of the foregoing, we are amending 49 CFR Chapter I, 
Subchapter C as follows:

PART 173--SHIPPERS--GENERAL REQUIREMENTS FOR SHIPMENT AND PACKAGES

0
1. The authority citation for part 173 continues to read as follows:

    Authority: 49 U.S.C. 5101-5128, 44701; 49 CFR 1.45, 1.53.


0
2. In Sec.  173.301, paragraph (d) is revised and a new paragraph (o) 
is added to read as follows:


Sec.  173.301  General requirements for shipment of compressed gases 
and other hazardous materials in cylinders, UN pressure receptacles and 
spherical pressure vessels.

* * * * *
    (d) Gases capable of combining chemically. A filled cylinder may 
not contain any gas or material capable of combining chemically with 
the cylinder's contents or with the cylinder's material of 
construction, so as to endanger the cylinder's serviceability.
* * * * *
    (o) DOT 3AL cylinders made of aluminum alloy 6351-T6. A DOT 3AL 
cylinder manufactured of aluminum alloy 6351-T6 may not be filled and 
offered for transportation or transported with pyrophoric gases.

0
3. In Sec.  173.302, a new paragraph (e) is added to read as follows:


Sec.  173.302  Filling of cylinders with nonliquefied (permanent) 
compressed gases.

* * * * *
    (e) DOT 3AL cylinders manufactured of 6351-T6 aluminum alloy. 
Suitable safeguards should be provided to

[[Page 51128]]

protect personnel and facilities should failure occur while filling 
cylinders manufactured of aluminum alloy 6351-T6 used in self-contained 
underwater breathing apparatus (SCUBA), self-contained breathing 
apparatus (SCBA) or oxygen service. The cylinder filler should allow 
only those individuals essential to the filling process to be in the 
vicinity of the cylinder during the filling process.

PART 180--CONTINUING QUALIFICATION AND MAINTENANCE OF PACKAGINGS

0
4. The authority citation for part 180 continues to read as follows:

    Authority: 49 U.S.C. 5101-5128; 49 CFR 1.53.


0
5. In Sec.  180.205, paragraph (f)(4) is revised to read as follows:


Sec.  180.205  General requirements for requalification of 
specification cylinders.

* * * * *
    (f) * * *
    (4) In addition to other requirements prescribed in this paragraph 
(f), each specification cylinder manufactured of aluminum alloy 6351-T6 
and used in self-contained underwater breathing apparatus (SCUBA), 
self-contained breathing apparatus (SCBA), or oxygen service must be 
inspected for sustained load cracking in accordance with Appendix C of 
this part at the first scheduled 5-year requalification period after 
January 1, 2007, and every five years thereafter.
* * * * *

0
6. In Sec.  180.209, in paragraph (a), in the ``Requalification of 
Cylinders table'' the entry ``DOT 3AL'' is revised, and a new paragraph 
(m) is added to read as follows:


Sec.  180.209  Requirements for requalification of specification 
cylinders.

* * * * *
    (a) * * *

               Table 1.--Requalification of Cylinders \1\
------------------------------------------------------------------------
                                     Minimum test
    Specification under which      pressure (psig.)     Requalification
        cylinder was made                 \2\           period (years)
------------------------------------------------------------------------
 
                              * * * * * * *
DOT 3AL.........................  5/3 times service   5 or 12 (see Sec.
                                   pressure.            180.209(j) and
                                                       Sec.
                                                       180.209(m)
                                                       \3\ ).
 
                              * * * * * * *
------------------------------------------------------------------------
\1\ Any cylinder not exceeding 2 inches outside diameter and less than 2
  feet in length is excepted from volumetric expansion test.
\2\ For cylinders not marked with a service pressure, see Sec.
  173.301(e)(1) of this subchapter.
\3\ This provision does not apply to cylinders used for carbon dioxide,
  fire extinguisher or other industrial gas service.

* * * * *
    (m) DOT-3AL cylinders manufactured of 6351-T6 aluminum alloy. In 
addition to the periodic requalification and marking described in Sec.  
180.205, each cylinder manufactured of aluminum alloy 6351-T6 used in 
self-contained underwater breathing apparatus (SCUBA), self-contained 
breathing apparatus (SCBA), or oxygen service must be requalified and 
inspected for sustained load cracking in accordance with the non-
destructive examination method described in the following table. Each 
cylinder with sustained load cracking that has expanded into the neck 
threads must be condemned in accordance with Sec.  180.205(i). This 
provision does not apply to cylinders used for carbon dioxide, fire 
extinguisher or other industrial gas service.

               Requalification and Inspection of DOT-3AL Cylinders Made of Aluminum Alloy 6351-T6
----------------------------------------------------------------------------------------------------------------
                                                                       Sustained Load Cracking   Requalification
      Requalification requirement         Examination procedure \1\   Condemnation Criteria \2\   period (years)
----------------------------------------------------------------------------------------------------------------
Eddy current examination combined with   Eddy current--In            Any crack in the neck or                5
 visual inspection.                       accordance with Appendix    shoulder of 2 thread
                                          C of this part.             lengths or more.
                                         Visual inspection--In
                                          accordance with CGA
                                          Pamphlet C-6.1 (IBR; see
                                          Sec.   171.7 of this
                                          subchapter).
----------------------------------------------------------------------------------------------------------------
\1\ The requalifier performing eddy current must be familiar with the eddy current equipment and must
  standardize (calibrate) the system in accordance with the requirements provided in Appendix C to this part.
\2\ The eddy current must be applied from the inside of the cylinder's neck to detect any sustained load
  cracking that has expanded into the neck threads.


0
7. In Sec.  180.213, paragraph (d) is revised and a new paragraph 
(f)(9) is added to read as follows:


Sec.  180.213  Requalification markings.

* * * * *
    (d) Requalification markings. Each cylinder successfully passing 
requalification must be marked with the RIN set in a square pattern, 
between the month and year of the requalification date. The first 
character of the RIN must appear in the upper left corner of the square 
pattern; the second in the upper right; the third in the lower right; 
and the fourth in the lower left. Example: A cylinder requalified in 
September 2006, and approved by a person who has been issued RIN 
``A123'', would be marked plainly and permanently into the metal of the 
cylinder in accordance with location requirements of the cylinder 
specification or on a metal plate permanently secured to the cylinder 
in accordance with paragraph (b) of this section. An example of the 
markings prescribed in this paragraph (d) is as follows:

                                   A1
                                  9 06 X
                                   32
 


Where:


``9'' is the month of requalification

``A123'' is the RIN

[[Page 51129]]


``06'' is the year of requalification, and

``X'' represents the symbols described in paragraphs (f)(2) through 
(f)(9) of this section.
* * * * *
    (f) * * *
    (9) For designation of the eddy current examination combined with a 
visual inspection, the marking is as illustrated in paragraph (d) of 
this section, except the ``X'' is replaced with the letters ``VE.''

0
8. In part 180, Appendix C is added to read as follows:

Appendix C to Part 180--Eddy Current Examination With Visual Inspection 
for DOT 3AL Cylinders Manufactured of Aluminum Alloy 6351-T6

    1. Examination Procedure. Each facility performing eddy current 
examination with visual inspection must develop, update, and 
maintain a written examination procedure applicable to the test 
equipment it uses to perform eddy current examinations.
    2. Visual examinations. Visual examinations of the neck and 
shoulder area of the cylinder must be conducted in accordance with 
CGA pamphlet C-6.1 (IBR; see Sec.  171.7 of this subchapter).
    3. Eddy Current Equipment. A reference ring and probe for each 
DOT-3AL cylinder manufactured of aluminum alloy 6351-T6 to be 
inspected must be available at the examination facility. Eddy 
current equipment must be capable of accurately detecting the 
notches on the standard reference ring.
    4. Eddy Current Reference Ring. The reference ring must be 
produced to represent each cylinder to be tested. The reference ring 
must include artificial notches to simulate a neck crack. The size 
of the artificial notch (depth and length) must have a depth less 
than or equal to \1/3\ of the wall thickness of the neck and a 
length greater than or equal to two threads. The standard reference 
must have a drawing that includes the diameter of the ring, and 
depth and length of each notch.
    5. Condemnation Criteria. A cylinder must be condemned if the 
eddy current examination combined with visual examination reveals 
any crack in the neck or shoulder of 2 thread lengths or more.
    6. Examination equipment records. Records of eddy current 
inspection equipment shall contain the following information:
    (i) Equipment manufacturer, model number and serial number.
    (ii) Probe description and unique identification (e.g., serial 
number, part number, etc.).
    7. Eddy current examination reporting and record retention 
requirements. Daily records of eddy current examinations must be 
maintained by the person who performs the requalification until 
either the expiration of the requalification period or until the 
cylinder is again requalified, whichever occurs first. These records 
shall be made available for inspection by a representative of the 
Department on request. Eddy current examination records shall 
contain the following information:
    (i) Specification of each standard reference ring used to 
perform the eddy current examination.
    (ii) DOT specification or exemption number of the cylinder; 
manufacturer's name or symbol; owner's name or symbol, if present; 
serial number; and, date of manufacture.
    (iii) Name of test operator performing the eddy current 
examination.
    (iv) Date of eddy current examination.
    (vi) Acceptance/condemnation results (e.g. pass or fail).
    (vii) Retester identification number.
    8. Personnel Qualification Requirements. Each person who 
performs eddy current and visual examinations, and evaluates and 
certifies retest results must be certified by the employer that he/
she has been properly trained and tested in the eddy current and 
visual examination procedures.
    9. Training Records. A record of current training must be 
maintained for each employee who performs eddy current and visual 
examinations in accordance with Sec.  172.704(d).

    Issued in Washington, DC, on August 22, 2006, under authority 
delegated in 49 CFR part 1.
Thomas J. Barrett,
Administrator.
 [FR Doc. E6-14255 Filed 8-28-06; 8:45 am]
BILLING CODE 4910-60-P