Notation 7772F: The National Transportation Safety Board (NTSB) has reviewed the Pipeline and Hazardous Materials Safety Administration’s (PHMSA) notice of proposed rulemaking (NPRM), “Hazardous Materials: Transportation of Lithium Batteries,” that was published at 75 Federal Register 1302 on January 11, 2010. The NPRM requests comments on revisions to the requirements for the transportation of lithium batteries in the Hazardous Materials Regulations (HMRs). The primary purpose of the NPRM is to enhance the safe transportation of primary (non-rechargeable) and secondary (rechargeable) lithium batteries when transported as cargo in all modes, with an emphasis on aviation. The NTSB believes that PHMSA has proposed requirements that should improve the level of safety for transporting lithium battery cargoes, particularly on aircraft. However, the NTSB offers the following comments to strengthen and clarify the proposed rule.
The NPRM proposes new requirements that address Safety Recommendations A-07-104, A-07-105, and A-07-107 through -109 that were issued as a result of the NTSB’s 2006 investigation of an in-flight cargo fire on a cargo airplane at Philadelphia International Airport in Philadelphia, Pennsylvania. The NPRM specifically addresses these safety recommendations through proposed requirements concerning the stowage of lithium batteries, the reporting and analysis of lithium battery failures, and the elimination of regulatory exceptions for small lithium batteries. The NTSB has included detailed comments about each of these areas in subsequent sections of this letter. The NTSB notes that PHMSA also proposes other requirements, and those are addressed as well.
The NPRM does not address Safety Recommendations A-08-1 and -2, which were issued separately from the Philadelphia accident report but also pertain to the transportation of lithium batteries. Safety Recommendations A-08-1 and -2 concern the implementation and evaluation of public awareness programs for air passengers and crews who carry portable electronic devices containing lithium batteries or pack spare lithium batteries in their baggage or carry-on items. The NTSB notes that PHMSA plans to address these two recommendations under a separate rulemaking. However, because of the proliferation of personal electronic devices carried by the traveling public, the NTSB urges PHMSA to expedite its rulemaking regarding these recommendations.
Stowage of Lithium Batteries
Cargo shipments of primary lithium batteries have been prohibited on passenger aircraft for more than 10 years, but they are still permitted on cargo-only aircraft. Cargo shipments of
secondary lithium batteries are permitted on both passenger and cargo-only aircraft. The transportation of primary lithium batteries is potentially dangerous, particularly on board aircraft, because there is currently no known fire suppression system capable of extinguishing fires involving these types of batteries. Fires involving secondary lithium batteries are extinguishable by fire suppression systems approved by the Federal Aviation Administration (FAA). Although fire suppression systems are required in cargo compartments of passenger aircraft, they are not required in cargo-only aircraft. The investigation of the Philadelphia accident showed that flight crews on cargo-only aircraft remain at risk from in-flight fires involving primary lithium batteries and from fires involving secondary lithium batteries on aircraft not equipped with fire suppression systems. Consequently, the NTSB issued the following recommendations to PHMSA:
Require aircraft operators to implement measures to reduce the risk of primary lithium batteries becoming involved in fires on cargo-only aircraft, such as transporting such batteries in fire resistant containers and/or in restricted quantities at any single location on the aircraft. (A-07-104)
Until fire suppression systems are required on cargo-only aircraft, as asked for in Safety Recommendation A-07-99, require that cargo shipments of secondary lithium batteries, including those contained in or packed with equipment, be transported in crew-accessible locations where portable fire suppression systems can be used. (A-07-105)
The NTSB believes that the NPRM fully addresses Safety Recommendation A-07-105 but only partially addresses Safety Recommendation A-07-104. The proposed rule would require that if either primary or secondary lithium batteries are transported in inaccessible cargo compartments or freight containers, the compartments or containers must be equipped with an FAA-approved fire suppression system, or that the packages of batteries must be transported in an FAA-approved fire-resistant container. Because current FAA-approved suppression systems are ineffective on fires involving primary lithium batteries, the NTSB believes that the NPRM would be improved if it explicitly required that shipments of primary lithium batteries be transported in FAA-approved fire-resistant containers. When the FAA approves a fire suppression system that is proven to be effective on fires involving primary lithium batteries, the NTSB would consider such a suppression system an acceptable alternative to an FAA-approved fire-resistant container. Because current FAA-approved fire suppression systems are effective on fires involving secondary lithium batteries, the NTSB supports the NPRM in that it would require that inaccessible shipments of secondary lithium batteries be transported in either cargo compartments or freight containers equipped with an FAA-approved fire suppression system or in FAA-approved fire-resistant containers.
PHMSA states in the NPRM that it is considering whether a limit on the number of primary lithium battery packages transported in a single airplane or single container would further enhance safety. Although PHMSA acknowledges the cumulative effect and the potential risks of packaging thousands of small primary batteries in close proximity, it has not proposed any requirements to mitigate the risks. The NTSB believes that the NPRM would be improved if restrictions were imposed on the clustering of primary lithium battery shipments on cargo-only aircraft.
Reporting and Analysis of Lithium Battery Failures
In the Philadelphia accident report, the NTSB noted that the causes of secondary lithium battery failures are not well understood or documented. The NTSB suggested that this may be due, in part, to the fact that proper evaluation of failed lithium batteries is not always performed, and that, in many cases, these batteries are disposed of before the incident is reported, precluding an accurate analysis of the failures. As a result, the NTSB issued the following recommendations to PHMSA:
Require commercial cargo and passenger operators to report to the Pipeline and Hazardous Materials Safety Administration all incidents involving primary and secondary lithium batteries, including those contained in or packed with equipment, that occur either on board or during loading or unloading operations and retain the failed items for evaluation purposes. (A-07-107)
Analyze the causes of all thermal failures and fires involving secondary and primary lithium batteries and, based on this analysis, take appropriate action to mitigate any risks determined to be posed by transporting secondary and primary lithium batteries, including those contained in or packed with equipment, on board cargo and passenger aircraft as cargo; checked baggage; or carry-on items. (A-07-108)
On July 31, 2008, PHMSA published an NPRM to revise requirements for the transportation of battery-powered devices and batteries and to harmonize the U.S. Department of Transportation HMRs with international standards. The NPRM included a proposal to require that all incidents involving lithium batteries and devices containing them be immediately reported. In a letter dated November 19, 2008, the NTSB suggested that the NPRM could be improved by also requiring that failed lithium batteries and associated equipment be retained in order to ensure proper analysis. The reporting requirement was included in the final rule published on January 14, 2009; however, the retention requirement was not. The NTSB is disappointed that the current NPRM also does not propose the retention requirement, but only requests comments about how retention of failed batteries and equipment might be achieved and a proper analysis conducted.
The NPRM notes that available incident data suggest that the most likely causes of lithium battery incidents are
• External short circuiting (an exposed battery terminal contacts a metal object).
• In-use situation (improper charging or discharging conditions associated with the use of equipment, including inadvertent activation and overheating).
• Noncompliance (faulty battery design, false certification, or improper packaging).
• Internal short circuit (foreign matter within the cell or battery, or physical damage).
However, PHMSA does not discuss the reliability of the data used to determine these causes, and the NTSB is concerned that such determinations are being made without retaining and analyzing failed batteries. In the absence of sound failure analyses, the establishment of the appropriate and effective transportation requirements is questionable, and without a regulatory requirement to retain failed batteries and a program to analyze the retained batteries and equipment, the NPRM fails to fully address Safety Recommendations A-07-107 and -108. The NTSB believes that the proposed rule would be significantly improved if retention and analysis of failed batteries and equipment were required.
Elimination of Regulatory Exceptions for Small Lithium Batteries
The NTSB’s investigation of the Philadelphia accident also dealt with regulatory exceptions for packages of small secondary lithium batteries, such as those used to power laptop computers, cameras, cell phones, and other personal electronic devices. Under these exceptions, based on battery power, size, and weight, certain shipments of small batteries are exempt from the hazardous materials packaging and identification requirements. The exceptions allowed batteries to be shipped undetected on both cargo and passenger aircraft. Because small secondary lithium batteries have been involved in at least nine documented aviation incidents and their failure modes are not fully understood, the NTSB expressed concern about the exceptions. The NTSB stated that cargo shipments of small lithium batteries should be subject to the same packaging and identification requirements that apply to medium and large lithium batteries in order to increase public and industry awareness of the risks associated with these batteries and to alert package handlers to exercise greater care when loading and unloading packages containing them. Consequently, the NTSB issued the following recommendation to PHMSA:
Eliminate regulatory exemptions for the packaging, marking, and labeling of cargo shipments of small secondary lithium batteries (no more than 8 grams equivalent lithium content) until the analysis of the failures and the implementation of risk-based requirements asked for in Safety Recommendation A-07-108 are completed. (A-07-109)
The NPRM proposes to eliminate the regulatory exceptions for lithium cells and batteries transported on board aircraft. The proposal would require that all lithium cells and batteries be regulated as class 9 materials in air transportation and subjected to the requirements found in Title 49 Code of Federal Regulations (CFR) 173.185, including the packaging standards and the hazard communication requirements. Adoption of this proposal would ensure that all lithium battery shipments are packaged appropriately and that packages are clearly labeled, providing a visible indication of the presence of hazardous material. The proposal also would ensure that all aviation shipments of lithium batteries are listed on the notice to the pilot in command.
The NTSB fully supports the proposal to eliminate exceptions for small lithium batteries and believes that the proposal, if implemented, will satisfy the intent of Safety Recommendation A-07-109.
Other Proposed Requirements
The NPRM proposes new requirements that have not been the subject of NTSB safety recommendations. The new proposals are discussed below.
The NPRM proposes to change all references to primary and secondary lithium batteries in the HMRs to “lithium metal batteries” and “lithium ion batteries,” respectively. Because the chemistry, functionality, and fire exposure behavior of lithium metal batteries and lithium-ion batteries are notably different, PHMSA identified a need to distinguish between them. As a result, the NPRM proposes creating separate shipping names and entries for lithium metal and lithium-ion batteries, reassigning existing United Nations (UN) identification numbers for lithium batteries to lithium metal batteries, and creating new UN identification numbers for lithium-ion batteries. These changes would facilitate the development and implementation of transportation requirements that are most appropriate for each battery type.
The NPRM proposes to adopt a methodology for determining the relative hazard associated with lithium-ion batteries by using measurements of watt-hours instead of equivalent lithium content. The NTSB agrees with PHMSA’s assessment that “watt-hours” is a more commonly used unit of measurement that is easier to calculate and understand.
The NPRM notes that most of the recent lithium battery incidents in the aviation industry have involved noncompliant shipments. PHMSA contends that noncompliance often results from confusion regarding regulatory requirements, which in turn results from a lack of proper training. The NPRM points out that while shippers of small lithium batteries are currently exempted from the training requirements found in 49 CFR Part 172, Subpart H, the proposal to eliminate regulatory exceptions for shipments of small lithium batteries would require that these shippers train employees who prepare such shipments. PHMSA believes that the training would ensure that employees are knowledgeable about applicable regulatory requirements and that shipments conform to the requirements, which would ultimately result in a reduction of lithium battery incidents. The NTSB supports these additional proposals.
The NTSB appreciates the opportunity to comment on this proposed rule and PHMSA’s continuing efforts to improve the safety of lithium battery transportation. Should you require any additional information or clarification, please contact us.