ProgPrraogmramDDeevveelolpompenmt ent Ba tte ry Safe ty A look at Woods Hole Oceanographic Institution’s program By Ronald H. Reif, Mark Liffers, Ned Forrester and Ken Peal

WOODS HOLE OCEANOGRAPHIC INSTITUTION ured in ampere-hours, Ah), higher (WHOI) uses primary and secondary lithium batteries (as measured in watt-hours per unit weight, Wh/g) in a variety of oceanographic research applications. and lower cost per capacity. WPrimary (nonrechargeable) lithium batteries generally The Ah rating or capacity is a common battery rat - contain lithium metal, while most secondary (re- ing that is the maximum sustained amperage drawn chargeable) lithium batteries contain an ionic form of from a fully charged battery over a certain time (e.g., lithium (lithium-). Because lithium batteries contain 20 hours) to a point where the battery is at 100% depth more energy per unit weight or a relatively higher of discharge. Energy density is a ratio of the capacity energy density than conventional batteries, they have of a battery to weight (Ah/g). Sometimes, energy den - become popular and widely used in various applica - sity is expressed as capacity per unit volume of a bat - tions. The same properties that result in a high energy tery, Ah/cm 3. Batteries also can be rated in energy density, however, also contribute to potential hazards output if their average voltage during discharge is if the energy is released at a fast, uncontrolled rate. known. Energy output is determined by multiplying Multiple external and internal events involving capacity and voltage with units of watt-hours (Wh). primary and secondary lithium batteries (including Secondary or lithium-ion (Li-ion) batteries, not to hot cells, fires, ruptured cells and leaking cells) be confused with primary lithium batteries, do not prompted WHOI to develop and implement a com - contain metallic lithium. Li-ion batteries are recharge - prehensive lithium battery safety program. This arti - able batteries containing lithium intercalation cle describes lithium batteries and applications, materials, where the lithium ion moves from the hazards, controls, key elements of a comprehensive anode to the during discharge and from the safety program, emergency procedures, waste man - cathode to the anode when charging. Advantages of agement and transportation requirements. Li-ion batteries when compared to equivalent re- chargeable batteries include higher energy density, Lithium Batteries & Applications higher output voltage, lighter weight, no memory Primary lithium batteries have lithium metal or effect, low self-discharge rate and faster charge rates; lithium compounds as an anode. Many different in addition, they do not contain highly toxic metals lithium battery chemistries are suitable for a variety such as nickel, cadmium, lead and mercury. of operating conditions. Advantages of lithium bat - Lithium batteries can be used in place of ordinary teries compared to alkaline batteries include lower alkaline cells in many devices. Although more costly weight, extended shelf life, higher capacity (as meas - initially, lithium cells provide much longer life, there - by minimizing battery replacement. Lithium batter - Ronald H. Reif, P.E., CSP, CIH, CHP, is the environmental, health and safety ies find application in many long-life, critical devices, director at the Woods Hole Oceanographic Institution (WHOI) in Woods Hole, MA. such as artificial pacemakers and other implantable He also serves as WHOI’s radiation safety officer, laser safety officer, biosafety electronic medical devices. Small lithium batteries officer and emergency coordinator. Before joining WHOI, Reif held various are commonly used in small, portable electronic positions within the U.S. Department of Energy complex, environmental devices, such as watches, digital cameras, remote car restoration sites, analytical laboratories and nuclear facilities. He holds a B.S. and starters and calculators, and as backup batteries in an M.S. in Physics from the University of Lowell and an M.S. in Environmental and computers and communication equipment. Waste Management from State University of New York at Stony Brook. Li-ion batteries are common in portable con - Mark Liffers, M.S., CSP, CIH, is president of Around The Compliance Inc. in sumer electronics, such as cell phones and laptop Hingham, MA. He is a member of ASSE’s Greater Boston Chapter. computers, because of their high energy-to-weight ratios, lack of memory effect and relatively slow loss Ned Forrester is a senior engineer at WHOI. He holds a B.S. and an M.S. in of charge when not in use. In addition to consumer Electrical Engineering from Massachusetts Institute of Technology. electronics, Li-ion batteries are increasingly used in Ken Peal, M.A.Sc., is a senior engineer at WHOI. He holds a B.Eng. from defense, automotive, aerospace and research appli - McMaster University and an M.A.Sc. from the University of British Columbia. cations due to their high energy density. 32 PROFESSIONAL SAFETY FEBRUARY 2010 www.asse.org WHOI uses both primary lithium batteries and ious OBS components include lithium sulfuryl chlo - Li-ion batteries in various applications. One applica - ride cells and lithium cells. Com- tion example for Li-ion batteries is the remote envi - plete packs for each OBS typically require between ronmental monitoring units (REMUS), a type of 100 and 150 lithium battery cells. These are D and autonomous underwater vehicle (AUV). AUVs are double D-sized cells with a rated voltage of 3.6 to 3.9 robotic submarines that navigate at 3 to 5 knots V and rated cell capacities of 15 to 35 Ah. Photo 3 without being operated by a human crew. They are shows opened glass spheres with a) part of the bat - used for both scientific research and military opera - tery pack and b) the electronics. Photo 4 shows the tions, such as locating mines. long deployment OBS. There are several versions of REMUS. The REMUS-100 uses four 250 Wh battery modules each Lithium Battery Hazards containing 14 Li-ion cells that are arranged as 7 in From 2004 to 2008, WHOI experienced multiple series and 2 in parallel, yielding a nominal output of incidents involving primary lithium batteries. These 26 V and a total energy of 1,000 Wh. The REMUS- included off-gassing cells, leaking cells, hot cells and a Photo 1 (top) shows 6000, which operates to 6,000 m depth, is loaded fire/explosion. A November 2005 event involved a a REMUS-100 Li-ion with a pair of 5.5 kWh rechargeable Li-ion battery fire and subsequent explosion of an OBS that had been battery assembly assemblies containing a total of 16 battery modules deployed offshore near Puerto Rico. The fire occurred while Photo 2 (mid - each providing 690 Wh. Photo 1 shows the REMUS- aboard a research vessel approximately 30 hours after dle) shows a pair of 100 Li-ion battery assembly and Photo 2 shows a recovery from the ocean and during the data offload - REMUS-6000 battery pair of REMUS-6000 battery assemblies. ing phase. Fortunately, no injuries occurred. assemblies. An application example of primary lithium bat - teries is ocean bottom seismographs (OBS), which are ocean floor seismic-monitoring instruments. OBS measure both earthquake-generated seismic waves and artificial sources. Two types of OBS are operated at WHOI: short-deployment and long- deployment. Short-deployment OBS are relatively small and light for easy deployment and recovery. With a 6-month battery capacity, they are designed for relatively short-term experiments and record high frequency earth motions. Long-deployment OBS can be deployed for a year or more to record earth motions. Four orange fiberglass “hardhats” that are mounted on a plastic grillwork contain primary lithium batteries and elec - tronics. A differential pressure gauge measures earthquake-generated waves in the water. The seis - mometer sensor is housed in a metal sphere sus - pended by a corrodible link. When an OBS is deployed, the link corrodes, positioning the seis - mometer on the seafloor. The primary lithium batteries used to power var -

Photo 3 (a & b): Two opened glass spheres, one with primary lithium batteries (left) and one with electronics (right). www.asse.org FEBRUARY 2010 PROFESSIONAL SAFETY 33 Photo 4: In this long batteries are engulfed in the fire. It was determined deployment ocean that the Halon fire extinguishing systems used in bottom seismograph, aircraft cargo compartments would not extinguish four orange fiberglass the primary lithium battery fire and that the pres - “hardhats” are mount - sure pulse from the burning batteries had the poten - ed on a plastic grill - tial to breach the cargo compartment liner and work containing spread the fire into the aircraft. primary lithium batter - Rechargeable Li-ion batteries have also been evalu - ies and electronics. ated by FAA (2006). These batteries also came under the scrutiny of DOT and FAA following the in-flight fire on a United Parcel Service DC-8 freighter aircraft Based on an internal investigation, the direct that was on approach to land in Philadelphia in 2006 cause of the fire and subsequent explosion was the (NTSB, 2007). However, FAA concluded that Halon unintended application of external voltage to a pri - was able to extinguish the Li-ion battery fire in the test. mary lithium battery pack housed in a sealed glass Regarding transportation safety, DOT concluded sphere that was not protected with an output diode. that lithium batteries, like other products which con - The investigation identified corrective actions, tain hazardous materials, can be transported safely including both engineering and administrative con - provided appropriate precautions are taken in design, trols, to help prevent recurrence of this incident. For packaging, handling and emergency response. With comparison, Photo 5 presents the undamaged bat - respect to lithium battery risks, DOT (2007) states that tery pack, where layers A-D represent the various 1) the risks that a lithium battery will short-circuit or lithium battery cell layers that make up the battery rupture are a function of design, packaging and han - pack, and Photo 6 shows a damaged battery pack dling; and 2) the degree of risk posed is largely a func - from the OBS after the fire and explosion. tion of the amount of stored energy. Since 2000, tens of millions of Li-ion batteries have been recalled by various battery, computer and Comprehensive Safety Program electronics manufacturers including Acer, Apple, In response to the various internal and external Dell, Kyocera, Hewlett-Packard, Lenovo, Nokia and incidents involving primary and secondary lithium Sony (CPSC, 2009). These recalls were prompted by batteries, WHOI developed a comprehensive lithi - reports of batteries overheating and the potential for um battery safety program in 2006. The program is cell fires and explosions. integrated into WHOI’s overall safety management Compared to other rechargeable batteries (e.g., program, which includes routine safety inspections, nickel metal hydride, nickel cadmium), Li-ion bat - accident/incident reporting and investigation, train - teries are not as durable and can become hazardous ing and other key program elements. The intent of if mishandled. They may explode if overheated or if the safety inspection program is to proactively iden - charged to an excessively high voltage and require tify and correct hazardous conditions. The acci - internal protection circuitry to help maintain safe dent/incident program is designed to identify the operation (GPIL, 2009). In response to the hazards causes of accidents and incidents, share lessons posed by primary and secondary lithium batteries, learned and prevent recurrence. UL (2005) issued a lithium battery standard. Key elements of the lithium battery safety pro - In December 2004 and again in August 2007, gram include documented safety guidelines and DOT (2004; 2007; 2009) tightened its safety standards training. These guidelines address storage, handling, for transport of primary and secondary lithium bat - hazard analysis, battery pack design and fabrication, teries. This regulatory action was in response to mul - shipment, waste management and emergency situa - tiple fires involving lithium batteries, including a tions. These guidelines are available on the institute’s significant fire that occurred at Los Angeles website, http://ehs.whoi.edu . Lithium battery safety International Airport (LAX) on April 28, 1999, which training is provided for personnel who design, han - involved two pallets of primary lithium batteries. dle, fabricate, deploy and/or ship lithium and Li-ion DOT reported that the packages were damaged dur - battery packs and cells. Safety procedures during ing handling at LAX, the fire could not be extin - normal and emergency conditions are covered dur - guished with portable fire extinguishers and a fire ing this training. hose, and that the incident illustrated the unique transportation safety problems posed by lithium Hazard Analysis batteries. These include risk of rough handling in Battery pack designers and engineers are respon - transit, resulting short-circuiting and ignition of sible for performing a hazard analysis (system safe - adjacent batteries. ty analysis) to identify the various failure modes and DOT also considered the results of testing con - hazards associated with the proposed configuration ducted by Federal Aviation Administration (FAA, and type(s) and number of batteries used. Based on 2004) to determine the behavior of primary lithium this analysis, safety-related design and testing crite - batteries when exposed to fire in a simulated aircraft ria are incorporated into battery pack designs. As cargo compartment. FAA’s testing revealed that necessary, battery pack engineers and designers also once ignited, lithium metal batteries can self-propa - develop standard operating procedures that include gate the fire by igniting adjacent batteries until all methods to identify and mitigate possible battery 34 PROFESSIONAL SAFETY FEBRUARY 2010 www.asse.org Photo 5 (left) shows an undamaged bat - tery pack, where lay - ers A-D represent the various lithium bat - tery cell layers that make up the battery pack. Photo 6 (right) shows a damaged pri - mary lithium battery pack after fire and explosion in OBS.

cell and pack failures that may occur during assem - use series diodes to block any possible charging cur - bly, deployment, data acquisition/retrieval, trans - rent from entering through the discharge terminal. portation, storage and disassembly/disposal. •Cells fabricated into a battery pack should be of To increase the safety margin and decrease the the same age (lot code) and history. Partially dis - failure rate, the hazard analysis process should be charged or discharged cells should not be mixed in a implemented during the design phase. This can be pack or stored with new cells. critical for battery pack designs, where a single cell •Thermal cutoff or resetable polymeric, positive failure could give rise to an increased hazard, temperature coefficient resistors can be used to limit involving a fire with multiple cells or the entire bat - cell temperature rise when that rise is caused by tery pack. Numerous hazard analysis methods may external current flow through the protective device. be used, from simple/preliminary to more complex •Both the surrounding thermal environment and (Vincoli, 2006). Examples include energy trace and the heat output of a battery pack and/or individual barrier analysis, failure mode and effect analysis, cells should be evaluated. If the hazard analysis fault hazard analysis, fault tree analysis, hazard and determines that a remote means of monitoring cell operability study, preliminary hazard analysis and temperature may be needed, devices such as ther - what-if analysis. The method selected should be mocouples and infrared temperature sensors should appropriate for the system design. be considered. For larger packs or for batteries run at high output rates, additional thermal management Safer Battery Packs must be considered. For example, copper or alu - The design of a battery pack can adversely affect minum heat sinks could be incorporated into the the safety characteristics of individual cells. For pack design to effectively conduct excessive heat example, a series configuration may increase the away from the cells during discharge. potential for subjecting cells to forced over discharge •Cells connected in series should not contain conditions and parallel strings can lead to charging connections to cells within the string, other than for currents (ECP, 2006). Battery packs should be cell voltage monitoring. This will reduce the possi - designed to avoid conditions that lead to short-cir - bility of cells being unequally discharged. cuiting, forced over discharging, charging or heat - •Batteries should not be encapsulated without ing. This can be accomplished through proper first consulting the manufacturer. design and use of protective devices such as fuses, •Battery pack construction should take into thermal switches, heat sinks and diodes. account the need for cell vents. There should be an Based on the hazard analysis, feasible controls can unrestricted escape path for the fumes such that be identified and incorporated into the battery pack pressure does not build up in the battery pack or design. The intent of incorporating feasible controls housing. A vent mechanism should also be incorpo - during the design phase is to increase the likelihood rated in rigid housings to avoid rupture or an explo - that the battery packs will perform reliably and safe - sion in the event of overpressure. ly during their entire life cycle. In general, it is more •Shock and vibration requirements must be con - cost-effective to incorporate engineering controls sidered as well. All cells must be protected from during the design phase rather than after the battery excessive shock and vibration. packs have been fabricated. •Regulations specific to the mode of transportation Basic hazard controls and design recommenda - (air, land, water) to be used may limit the amount of tions that should be considered during the design lithium in any one container. Therefore, large packs phase include the following: may need to be designed in a modular fashion and •Always use the same size cells in series or paral - assembled in the field. Verify potential shipping lel connections. Do not mix cell chemistries and dif - requirements and limitations prior to the final design. ferent cell sizes. Follow manufacturer’s instructions and review MSDS for the battery cells being used. Fabrication & Storage •Primary lithium cells should not be connected to After the battery pack design is complete, the next a power source or otherwise charged. When possible, step is fabrication of the battery packs. During fabrica - www.asse.org FEBRUARY 2010 PROFESSIONAL SAFETY 35 WHOI’s Fire Extinguisher Criteria Battery type: Lithium, primary tion, it is important to follow the If a hot or vented cell situation exists, all person - nonrechargeable design drawings and associated nel should be evacuated from the area. The area Fire involves batteries only (cells procedures. In accordance with should be secured until the hot or vented cell is sta - or battery pack): Use Lith-X Class D quality control procedures, bat - bilized and removed. Hot cells that have been extinguishing agent. DO NOT use tery packs should be inspected cleared of any short-circuit and that have cooled to water. at various stages of production ambient temperature should be neutralized with Fire involves batteries and other and the proper design verified. sodium bicarbonate. Vented cells also should be surrounding materials: Use an ABC During and after fabrication, neutralized with sodium bicarbonate. After being dry chemical extinguisher or water battery cells and packs will need stabilized, hot and vented cells should be disposed hose stream. Fight the fire based on to be safely stored. Basic safety of as hazardous waste. the fueling material (e.g., paper, precautions that should be fol - Emergency equipment that may be needed for plastic, ). lowed during battery pack fab - responding to hot and vented lithium cells include: Battery type: Lithium-ion, sec - rication and storage include the •infrared temperature probe; ondary rechargeable following: •helmet with high-impact-resistant face shield; Fire involves batteries only (cells •Store cells in original manu - •body, arm, hand, eye, respiratory protection; or battery pack): Use an ABC dry facturer’s container until they •nonconductive extended pliers; chemical extinguisher or water hose are ready to be assembled into •Class D fire extinguisher; stream. Fight the fire based on the battery packs. Store primary •readily available emergency shower and eye - fueling material (e.g., paper, plastic, lithium cells in a cool, dry, well- wash; solvent). ventilated location. Significant •4 to 6 mil plastic bags with sealing mechanism; Fire involves batteries and other quantities of lithium batteries •sodium bicarbonate (baking soda) and univer - surrounding materials: Use an ABC may need to be isolated from sal absorbing material (e.g., vermiculite). dry chemical extinguisher or water flammable and combustible Lithium will burn in a normal atmosphere and hose stream. Fight the fire based on materials during fabrication and reacts explosively with water to form hydrogen. The the fueling material (e.g., paper, storage. This can be achieved presence of minute amounts of water may ignite the plastic, solvent). with flammable-rated cabinets. material and the hydrogen gas. Lithium fires can •Do not allow positive and also throw off highly reactive molten lithium metal negative leads to contact. particles. Cells adjacent to any burning material Loose wires should not be stripped until it is time to could overheat and ignite. install a connector, or the connector harnesses In general, an extinguishing agent that is best should be assembled before attaching them to the suited to extinguish the bulk of the fuel that is cell terminals. If no connector is used, wire ends involved in the fire should be used. For example, if a should be insulated. When cutting wires, only cut single primary lithium battery cell were to start one wire at a time. burning, a Lith-X (Class D) extinguisher should be •If available, use nonconductive tools and avoid used to extinguish the fire. If other combustibles placing battery cells and packs on electrically con - catch fire as result of the lithium battery, then use the ductive surfaces. appropriate extinguishing agent to extinguish these •Do not solder directly to cell case. Only solder to secondary fires. the free end of solder tabs that are welded to the case. Li-ion battery chemistry is not as safe as other •All battery packs should be appropriately labeled types, such as nickel metal with key information such as type of battery, its volt - hydride and nickel cadmium, and Li-ion batteries age, temperature limit, manufacturer name and date. may explode if overheated or if charged to an exces - Emergency Procedures sively high voltage (GPIL, 2009). FAA (2006) con - ducted a series of tests to determine flammability of As noted, WHOI has experienced the following Li-ion batteries and concluded that flames produced emergency scenarios with primary lithium batteries: by the batteries are hot enough to cause adjacent hot cells, vented cells, fires and explosions. In accor - cells to vent and ignite. dance with manufacturer’s instructions, emergency While primary lithium battery fires cannot be response procedures should be developed for each suppressed with Halon, FAA concluded that Halon possible scenario. Emergency response personnel is effective in suppressing Li-ion fires. Because there should be adequately trained in accordance with is no metallic lithium in an Li-ion battery, ordinary OSHA’s (2002) standard for hazardous waste opera - extinguishing agents (e.g., ABC extinguisher) can tions and emergency response. generally be used for these fires. However, it is The contained within primary lithium important to review the battery manufacturer’s cells can cause severe irritation to the respiratory tract, MSDS for the specific battery type to ensure that the eyes and skin. Depending upon the cell chemistries appropriate fire extinguishing agents and proce - (ECP, 2006), venting from primary lithium batteries dures are available. The sidebar at left presents could result in the release of hazardous substances WHOI’s generalized fire extinguisher selection crite - such as thionyl chloride, sulfuryl chloride, bromine, ria for lithium and Li-ion battery users. , hydrochloric acid, , highly acid wastewater and hydrogen gas from the reaction with Waste Management & Transportation water. Depending upon the cell chemistries, other WHOI has established universal and hazardous hazardous substances can be released as well. waste management programs that include docu - 36 PROFESSIONAL SAFETY FEBRUARY 2010 www.asse.org mented procedures, generator training, internal inspections, waste generation tracking, designated collection points, online waste pickup requests and waste minimization. It should be noted that there are significantly different regulatory requirements for management of universal and hazardous waste, including on-site accumulation times, labeling of collection containers, documentation (nonhaz - ardous waste versus uniform hazardous waste man - ifest) and generator weight limits. Primary lithium batteries that are damaged (e.g., vented or burned) must be managed as hazardous waste. Photo 7 shows a hot lithium battery cell that was effectively neutralized with sodium bicarbonate safety standards for and subsequently disposed of as hazardous waste. transport of lithium Unlike primary lithium batteries, undamaged Li-ion and Li-ion batteries. batteries are not considered hazardous waste and WHOI has experienced multiple incidents involv - Photo 7 (left) shows need not be managed as universal waste. While ing primary lithium batteries. In response to those neutralized lithium spent or used Li-ion batteries may not be regulated incidents and those reported throughout industry, battery cells being as a hazardous waste, DOT regulations must be WHOI developed a comprehensive lithium battery managed as haz - reviewed for applicable requirements. safety program. Since doing so, all lithium battery ardous waste. Photo Undamaged lithium batteries where the lithium pack designers, fabricators and users have been 8 (above) illustrates can be recovered and recycled can be managed as trained and are implementing applicable elements of a universal waste universal waste (EPA, 2005). Most spent or used pri - the program. The rate and severity of incidents collection point. mary lithium batteries are safely managed as uni - involving lithium batteries has significantly de- versal waste at WHOI. Universal waste collection creased at WHOI. Ⅲ sites (Photo 8) are located in most buildings on the institute’s two campuses. References In addition to training provided to lithium bat - Consumer Product Safety Commission (CPSC). (2009). tery users and waste generators, the lids on the col - Product recalls and safety news. Washington, DC: Author. lection containers are posted with the following: Retrieved Dec. 18, 2009, from http://www.cpsc.gov/cpscpub/ •Universal waste. Only lithium batteries may be prerel/prerel.html . DOT. (2004). Prohibition on the transportation of primary disposed in this container. lithium batteries and cells aboard passenger aircraft. Final Rule •Improper mixing of incompatible batteries (e.g., (49 CFR Parts 171-175). Federal Register, 69, 75208-75216. alkaline) could cause a release of toxic substances or DOT. (2007). Transportation of lithium batteries. Final Rule fire. (49 CFR Parts 171-175). Federal Register, 72, 44930-44950. DOT. (2009). Traveling safe with batteries. Washington, DC: •Battery cells and packs must be clearly labeled Author. Retrieved Dec. 18, 2009, from http://safetravel.dot.gov/ Lithium Batteries. whats_new _batteries.html . •All exposed terminals must be protected to pre - Electrochem Commercial Power (ECP). (2006). Safety and vent short circuiting. handling guidelines for Electrochem lithium batteries (15-SAF- •Never expose lithium batteries to water. Cor- 0043. Rev. B). Clarence, NY: Author. EPA. (2005). Standards for universal waste management. Title roded or otherwise damaged batteries must be col - 40 Part 273. Washington, DC: Author. lected as hazardous waste. Federal Aviation Administration (FAA). (2004). Flammability •Properly secure container lid after adding waste assessment of bulk-packed, nonrechargeable lithium primary batteries in batteries. transport category aircraft (DOT/FAA/AR-04/26). Washington, DC: Author. Retrieved Dec. 18, 2009, from http://www.fire.tc.faa.gov/ Waste pickup and emergency contact numbers pdf/04-26.pdf . are also noted. FAA. (2006). Flammability assessment of bulk-packed, rechargeable lithium-ion cells in transport category aircraft (DOT/FAA/AR- 06/38). Washington, DC: Author. Retrieved Dec. 18, 2009, from Conclusion http://www.fire.tc.faa.gov/pdf/06-38.pdf . Lithium and Li-ion batteries have become more Gold Peak Industries Ltd. (GPIL). (2009). Lithium ion technical popular and are widely used in a variety of applica - handbook. Tapei, Taiwan: Author. Retrieved Dec. 18, 2009, from http://www.gpbatteries.com.hk/html/pdf/Li-ion _handbook.pdf . tions, including consumer products, medical de- National Transportation Safety Board (NTSB). (2007). vices, research, military and other applications. The Accident report: In flight cargo fire United Parcel Service Co. Flight same properties that make these batteries more pop - 1307 McDonnell Douglas DC-8-71F, N748UP, Philadelphia, PA ular, such as higher capacity and higher energy den - (NTSB/AAR-07/07 PB2007-910408). Washington, DC: Author. Retrieved Dec. 18, 2009, from http://www.ntsb.gov/publictn/ sity, have increased the potential hazards when their 2007/AAR0707.pdf . energy is released at a fast, uncontrolled rate. OSHA. (2002). Hazardous waste operations and emergency Tens of millions of Li-ion batteries have been response (29 CFR 1910.120). Washington, DC: U.S. Department of recalled by manufacturers because of batteries over - Labor, Author. Underwriters Laboratories Inc. (UL). (2005). Standard for heating and the potential for cell fires and explo - lithium batteries (UL 1642). Northbrook, IL: Author. sions. In response to multiple fires involving air Vincoli, J.W. (2006). Basic guide to system safety (2nd ed.). transport of lithium batteries, DOT tightened the Hoboken, NJ: Wiley-Interscience. www.asse.org FEBRUARY 2010 PROFESSIONAL SAFETY 37