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Proposed Rule

Hazardous Materials: Safety Requirements for External Product Piping on Cargo Tanks Transporting Flammable Liquids

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Information about this document as published in the Federal Register.

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


Withdrawal of notice of proposed rulemaking.


PHMSA is closing this rulemaking proceeding, having considered and declined to adopt proposals for further regulating the transportation of flammable liquids in the product piping on cargo tank motor vehicles. On the basis of public comments and additional data and analysis, PHMSA has concluded that further regulation would not produce the level of benefits we originally expected and that the quantifiable benefits of proposed regulatory approaches would not justify the corresponding costs. Although PHMSA is withdrawing its rulemaking proposal, the agency will develop and implement an outreach program to educate the industry, first responder community, and the public about potential risks associated with unprotected product pipelines on these vehicles and will continue to collect data and other information in order to address the issue further if warranted.

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Ben Supko, Office of Hazardous Materials Standards, Pipeline and Hazardous Materials Safety Administration, telephone (202) 366-8553; or Michael Stevens, Office of Hazardous Materials Standards, Pipeline and Hazardous Materials Safety Administration, telephone (202) 366-8553.

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I. Background

On December 30, 2004 the Pipeline and Hazardous Materials Safety Administration (PHMSA, we) published a notice of proposed rulemaking (NPRM) (69 FR 78375) inviting comments on a proposal to amend the Hazardous Materials Regulations (HMR; 49 CFR parts 171-180) to prohibit the carriage of flammable liquids in the product piping (wetlines) on cargo tank motor vehicles (CTMVs), unless the CTMV is equipped with bottom damage protection devices. We proposed a quantity limit of one liter or less in each pipe. We did not propose a specific method for achieving this standard. The NPRM included an exception from the proposed requirements for truck-mounted (e.g., straight truck) DOT specification CTMVs. We proposed to make the changes effective two years after the effective date of a final rule and to permit CTMV operators five years to phase in requirements applicable to existing CTMVs.

II. Comments on the NPRM

We received thirty sets of public comments on the NPRM from a variety of stakeholders, including industry associations, companies, governmental entities, individuals and members of Congress, as follows:

CommenterDocument number
Maurice R. TetreaultRSPA-1999-6223-28
American Petroleum Institute (API)RSPA-1999-6223-32
Georgia Department of Motor Vehicle SafetyRSPA-1999-6223-33
Southwest Research InstituteRSPA-1999-6223-34
David M. LawlerRSPA-1999-6223-35
Dale L. BotkinRSPA-1999-6223-37
Public Utilities Commission of OhioRSPA-1999-6223-38
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National Transportation Safety Board (NTSB)RSPA-1999-6223-39
California Air Resources BoardRSPA-1999-6223-41
Magellan Midstream Partners, L.P.RSPA-1999-6223-42
Laura E. HermanRSPA-1999-6223-45
National Tank Truck Carriers, Inc. (NTTC)RSPA-1999-6223-46
Great Lakes Transport, LLCRSPA-1999-6223-48
Anthony C. PitfieldRSPA-1999-6223-49
The Dow Chemical Company (Dow)RSPA-1999-6223-50
Truck Trailer Manufacturers Association (TTMA)RSPA-1999-6223-51
Petroleum Marketers Association of America (PMAA)RSPA-1999-6223-52
Dangerous Goods Advisory CouncilRSPA-1999-6223-53
Saraguay Petroleum Corp (Saraguay Petroleum)RSPA-1999-6223-54
Petroleum Transportation and Storage Association (PTSA)RSPA-1999-6223-55
Baltimore Cargo Tank Services, Inc.RSPA-1999-6223-56
American Trucking Associations (ATA)RSPA-1999-6223-57
Cargo Tank Concepts, Ltd. (CTC)RSPA-1999-6223-58
Minnesota Trucking AssociationRSPA-1999-6223-59
Society of Independent Gasoline Marketers of America (SIGMA)RSPA-1999-6223-60
Brenner Tank LLCRSPA-1999-6223-61
Denny Rehberg, Member of CongressRSPA-1999-6223-62
The Honorable Thomas E. PetriRSPA-1999-6223-65
The Honorable Conrad BurnsRSPA-1999-6223-66
The Honorable Michael SodrelRSPA-1999-6223-67

The comments are available for review through DOT's electronic Docket Management System (on the Web site

Many of the commenters took issue with our original estimates of costs and benefits in the regulatory evaluation prepared in support of the NPRM. Generally, these commenters assert we underestimated the number of cargo tanks affected and the cost of retrofits and over-estimated the number and severity of wetlines incidents. Commenters also question the effectiveness, reliability, efficiency, and functionality of currently available technology to purge lading from wetlines.

III. Revised Regulatory Evaluation

Based on comments received in response to the NPRM, we re-evaluated the data and information concerning potential costs and benefits of regulatory alternatives to ensure that any final rule prohibiting the transportation of flammable liquids in unprotected wetlines would maximize the net benefit to society.

Our revised regulatory review included reassessment of the number of accidents involving wetlines and fatalities, injuries, and property damage resulting from those accidents. We also revised our estimate of the number of vehicles potentially affected by rulemaking action and the technology currently available to purge flammable liquids from wetlines to ascertain its effectiveness and practicability in the transportation environment. The following table summarizes the overall costs and benefits, calculated over a 20-year period using a seven percent discount rate, for the three options considered in the 2006 regulatory evaluation:

Present Value Costs and Benefits of Rule

AlternativesP.V. total costP.V. total benefitBenefit-cost ratio
Purging System on New Trucks$23,847,613$25,377,9851.06
Purging System on Trucks Manufactured on or After January 1, 200235,968,40138,902,7381.08
Purging System on New and Existing Trucks53,595,42250,945,4010.95

The revised regulatory evaluation assumes a total of 27,000 vehicles would be affected by a final rule, and the cost to install a purging system would be $1,600 per tank on newly manufactured CTMVs and $1,760 to retrofit existing CTMVs. We also assumed the average service life for a CTMV in flammable liquid service is 20 years; thus, five percent of the fleet would be retired each year.

In measuring the benefits of wetlines regulation, we considered avoided injuries, property damage, traffic delays, evacuations, emergency response, and environmental damage. These benefits are scaled to account for underreporting of wetlines incidents, particularly for the period prior to October 1998, when DOT incident reporting requirements were extended to intrastate operations.

In response to concerns expressed by commenters, we reexamined available data for each of the 190 incidents that had been attributed to wetlines in the original regulatory analysis, applying revised criteria to isolate those that, by virtue of their circumstances, could be verified as wetlines incidents. In 42 of these cases, we found that the incident-related injuries, property damage, and other costs could not be attributed to the risk associated with unprotected wetlines. For instance, the revised regulatory analysis excludes incidents in which both the wetline and the cargo tank were breached and does not include incidents involving spills of more than 50 gallons, unless a fire resulted from the spill. Using incident data reported to DOT from January 1, 1990 through December 31, 2001, we Start Printed Page 32911identified 148 CTMV incidents involving wetlines. These incidents resulted in seven fatalities, three injuries, and over $7 million in property damage.

Because of commenters' questions and concerns about many of the assumptions used to develop the regulatory evaluation for the NPRM, we performed a sensitivity analysis to calculate the benefits and costs of the three identified options by changing the variables used, including the number of affected vehicles, the installation costs for a non-welded purging system, and the number of wetlines incidents. PHMSA concludes from the sensitivity analysis that the benefit-cost ratios for the new-construction-only option could range from a low of .73/1 (assuming the highest possible costs and lowest possible benefits) to a high of 1.20/1 (assuming the lowest possible costs and highest possible benefits). A complete discussion of the sensitivity analysis is included in the regulatory evaluation in the public docket for this proceeding.

For purposes of the analysis in the regulatory evaluation, we identified an on-truck purging system as the low-cost alternative for compliance with the performance standard at issue in this rulemaking proceeding. The purging system utilizes 5 psi of air pressure from the CTMV's compressed air tanks to purge the loading lines. The system routes the product from the lowest point in the piping to the tank shell through 0.5 inch braided stainless steel lines. Purging the loading lines on a four-compartment cargo tank takes six minutes.

The purging system represents the lowest cost, most efficient solution available for the elimination of wetlines. However, as noted above, many commenters question the effectiveness, reliability, efficiency, and functionality of purging systems. We agree with commenters that the current technology may cause problems unrelated to the wetlines issue it is designed to address. Although most of these problems may be corrected or avoided, we have determined that the benefits of imposing solutions through regulation would not justify the costs of such action.

Finally, we note that the industry is taking action voluntarily to limit the safety risks associated with the transportation of flammable liquids in unprotected wetlines. One large gasoline distributor has installed purging systems on its CTMVs. Another large gasoline distributor has installed damage protection equipment on its CTMVs that could help to mitigate the consequences of a collision with an automobile or other vehicle. We urge the regulated community to continue its efforts voluntarily to identify and implement measures to address this issue. We also plan to develop and implement an outreach program to educate the industry, first responder community, and the public about the potential risks associated with wetlines. We will continue to collect relevant information concerning wetlines incidents and technological developments affecting wetlines transportation.

IV. Conclusion

In the final analysis, we did not identify a cost-effective approach for addressing the risk of wetlines transportation through regulatory action. Based on the revised regulatory evaluation, we believe the benefits of a final rule prohibiting the transportation of flammable liquids in wetlines only on newly constructed CTMVs may slightly outweigh the costs. However, given the sensitivity of the benefit-cost determinations to variations in the data and the inherent margin for error in the overall analysis, it is possible, even for newly constructed CTMVs, the costs of a regulatory solution will outweigh potential benefits.

Accordingly, PHMSA is withdrawing the December 30, 2004 NPRM and terminating this rulemaking proceeding.

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Issued in Washington, DC, on May 31, 2006, under authority delegated in 49 CFR part 1.

Brigham A. McCown,

Acting Administrator.

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[FR Doc. E6-8782 Filed 6-6-06; 8:45 am]