Environmental implications of electric cars

Reproduced with permission of the copyright owner. Further reproduction prohibited without permission.

Environmental implications of electric carsLave, Lester B; Hendrickson, Chris T; McMichael, Francis ClayScience; May 19, 1995; 268, 5213; Research Library Corepg. 993



© Copyright 1997 by the MassachusettsInstitute of Technology and Yale University

Volume 1, Number 1

The Industrial Ecologyof Lead and Electric VehiclesRobert SocolowValerie ThomasCenter for Energy and Environmental StudiesPrinceton UniversityPrinceton, New Jersey, USA

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Summary

The lead battery has the potential to become one of thefirst examples of a hazardous product managed in an en-vironmentally acceptable fashion. The tools of industrialecology are helpful in identifying the key criteria that anideal lead-battery recycling system must meet: maximal re-covery of batteries after use, minimal export of used bat-teries to countries where environmental controls areweak, minimal impact on the health of communities nearlead-processing facilities, and maximal worker protectionfrom lead exposure in these facilities. A well-known riskanalysis of electric vehicles is misguided, because it treatslead batteries and lead additives in gasoline on the samefooting and implies that the lead battery should be aban-doned. The use of lead additives in gasoline is a dissipativeuse where emissions cannot be confined; the goal of man-agement should be and has been to phase out this use. Theuse of lead in batteries is a recyclable use, because the leadremains confined during cycles of discharge and recharge.Here, the goal should be clean recycling. The likelihood thatthe lead battery will provide peaking power for severalkinds of hybrid vehicles—a role only recently identified—increases the importance of understanding the levels ofperformance achieved and achievable in battery recycling.A management system closely approaching clean recyclingshould be achievable.

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❙ T H E S TAT E O F T H E D E B AT E

Keywords

automotive technologybatterieselectric vehiclesindustrial ecologyleadleaded gasoline

Journal of Industrial Ecology 13

Address correspondence to:Robert SocolowCenter for Energy and Environmental

StudiesPrinceton UniversityH104 Engineering Quad(P.O. Box CN5263)Princeton, NJ [email protected]

Editor’s note: The debate over lead-acid batteries and electric vehiclescontinues in the second issue of the Journal of Industrial Ecology witha response to this article by Lave, Hendrickson and McMichael and arejoinder by Socolow and Thomas.


14 Journal of Industr ial Ecology

The Industrial Ecologyof a Hazardous Material

This article is about the two uses of lead incars—lead in gasoline and lead in batteries—and about how trying to relate the two to eachother has led to considerable confusion. Our in-tent is to show how the concepts and tools of in-dustrial ecology (Ayres 1994; Braungart 1994;Socolow 1994) can reduce this confusion.

From the point of view of industrial ecology,which sees the activities of industrialized societ-ies in terms of flows of materials out of and backinto the natural environment, these two uses oflead in automobiles could not be more different.The use of lead in a gasoline additive is a dissi-pative use; the use of lead in a battery is a recy-clable use.

The use of lead as a gasoline additive is a dis-sipative use, because during gasoline combustionthe lead is entrained with emissions at the car’stailpipe. After the lead leaves the tailpipe, it dis-perses in the air and is deposited on soil, crops,and other surfaces. People are exposed not onlyby inhalation but also through ingestion of food,dust, and soil. Total phaseout of lead additives inautomotive gasoline is a goal that is easy to defineand to compare with current practice. The goalhas already been reached in several countries.

The use of lead in a battery is a recyclable use,because all the lead is confined within the batteryas the battery undergoes its cycles of dischargeand recharge. Industrial ecology suggests that thegoal of lead management can be clean recyclinginstead of phaseout. Clean recycling requires nolead emissions into the environment except informs as isolated from human beings and ecosys-tems as the original lead in the ground. The toolsof public policy, including economics, can becombined with industrial ecology to help decidehow closely this goal should be approached, atany given state of technology.

Battery-associated lead leaves the industrialsystem only during lead processing, battery recy-cling, and battery manufacture. In the UnitedStates today, the recycling system for lead batter-ies is becoming more and more closed: only asmall percentage of lead batteries escapes recy-cling, and only a small percentage of the leadthat enters the battery recycling system becomes

environmental emissions. Moreover, on a massbasis, these environmental emissions are largelyin the form of bulk materials with low concen-trations of lead, and these bulk materials are fur-ther processed and managed to reduce thepotential for lead to be leached. Only a verysmall percentage of the lead emissions to theenvironment from the battery recycling systemis airborne particulates, the portion of greatestconcern from a public health standpoint. Im-pacts on the health of workers in recycling facili-ties and people in communities near thesefacilities are being reduced. For the lead in bat-teries, something close to the ideal of clean recy-cling should be achievable.1

The LRHM Analysis

The proximate stimulus for this article is thefact that the EV-1 Zero Emission Vehicles(ZEVs) now being delivered to General Motors’automobile showrooms in California and Ari-zona carry a rack of batteries containing 325 ki-lograms (kg), or about 700 pounds of lead. Lave,Hendrickson, and McMichael (1995) publishedan analysis of the fate of this lead in the PolicyForum in Science. Lave, Russell, Hendrickson,and McMichael (1996) carried the analysis fur-ther in the Environmental Policy Analysis fea-ture in Environmental Science and Technology,here called “the LRHM analysis”.2 Both articlesmake the startling assertion that the lead inthese electric vehicles will result in lead emis-sions exceeding those from leaded gasoline in asimilar gasoline-powered car.

As a way of attracting the attention of theenvironmental community, the idea of compar-ing lead in gasoline with lead in batteries forelectric cars is inspired. Getting the lead out ofgasoline has been one of the major successes ofenvironmental regulation. The electric car isnow achieving its initial commercialization inthe United States as a result of other environ-mental regulations. By suggesting that no self-respecting environmentalist should be cheeringfor the electric car, the analysis was certain togain widespread attention.

The LRHM analysis compares (1) lead emis-sions per kilometer (km) of driving for a gaso-line-powered car fueled with leaded gasoline,

Socolow and Thomas, Industrial Ecology of Lead and EVs 15

T H E S TAT E O F T H E D E B AT E ❙

and (2) lead emissions per kilometer of drivingfor an electric car powered by lead batteries. Thecalculation for the gasoline-powered car assumesthat the car consumes gasoline at a rate of 19.1km per liter (km/L), or 45 miles per gallon,about double the fuel economy of today’s cars. Itfurther assumes a lead concentration in the gaso-line of 0.56 grams per liter (g/L), or 2.1 grams pergallon, equal to the concentration in the UnitedStates in 1972, the peak year for lead consump-tion in U.S. gasoline. Lead emissions from sucha vehicle come to 29 milligrams (mg) per kilo-meter of driving.

For the battery-powered car, the LRHM analy-sis assumes that the mass of lead on board in bat-teries is 325 kg, as it is for the General Motors’EV-1. It further assumes that the battery will berecycled after two years of driving 19,300 km(12,000 miles) per year, and that 100% of the bat-tery lead is recycled. It follows that roughly 8,400milligrams of lead will arrive at the secondary (re-cycling) smelter for every kilometer of driving(about half an ounce of lead per mile).

The LRHM analysis assumes that total lead re-leases to the environment associated with batteryuse and recycling can be approximated by totallead releases at secondary smelters, the most de-manding step in recycling in terms of pollutioncontrol. Thus, the key parameter governing thiscomparison of electric cars with cars running onleaded gasoline is the fraction of the lead pro-cessed at the smelter that leaves the industrial sys-tem and enters the environment. If this parameteris more than about 29/8400, or 0.35%, then, perkilometer of driving, lead emissions to the envi-ronment will be greater for the electric car thanfor the car running on leaded gasoline. In theLRHM analysis, the fraction of the lead estimatedto escape the recycling process is about 1%, lead-ing to the result that the lead emissions from anelectric car are about three times greater than thelead emissions from a gasoline-powered car run-ning on leaded gasoline.3

Virtually all of the lead emissions from leadedgasoline are air emissions, but only a small frac-tion of the lead emissions from battery recyclingare air emissions. Thus, one will get a very differ-ent impression of the relative per-kilometer leademissions, if air emissions are compared insteadof total emissions. The LRHM analysis estimates

that the air emissions factor for secondary smelt-ing (air emissions divided by lead production) isabout 0.03%, and, therefore, that about 3% ofall emissions are air emissions.4

Are total releases or air releases the more ap-propriate quantity to compare? The LRHManalysis, while presenting both alternatives, pre-fers the use of total releases, on the grounds thatthere is a “potential for resuspension of fine par-ticulate matter containing lead and the weather-ing and leaching of lead to air and water fromsolid waste containing lead. . . . The total envi-ronmental discharges are the eventual burden,even though air emissions pose the greatest im-mediate threat” (Lave et al. 1996, 405, 406).There is no discussion of how a future burdenbecomes a future threat (how much lead mightbe leached from slag and enter drinking water,for example), or of whether future threats shouldbe discounted relative to present threats.

The LRHM analysis also quantifies the leademissions associated with the lead-acid starting-lighting-ignition (SLI) battery that providesstarting power for today’s cars. This battery is as-sumed to contain 8 kg of lead (40 times less thanthe lead in the battery of the reference electricvehicle) and to remain in the car for four years(twice as long), so that 80 times as much leadflows annually through an electric car with a leadbattery as flows through a car that contains leadonly in the SLI battery.5

The LRHM analysis concludes that the first-generation electric car powered by lead batteriesis “a potential environmental liability,” and im-plies that there is greater merit in pursuing thegasoline-powered car with advanced pollutioncontrol (Lave et al. 1996, 406). In the remainderof this article, we take issue with this way offraming the discussion. In section III we arguethat it is too early to remove the lead batteryfrom the list of technological options: the leadbattery may have several roles in future electricvehicles, not only the role discussed in theLRHM analysis. In section IV we argue, further,that there is reason for optimism that an envi-ronmentally responsible management system forlead batteries can be achieved. Quite generally,opportunities for creative policymaking are un-covered when it is widely agreed that choicesamong technologies can be made in more than



one step (Ross and Socolow 1991). With con-structive initatives coming from several direc-tions, a potential environmental liability doesnot have to become a real one.

Two Roles for the LeadBattery in the Future Vehicle

The electric vehicle, in various configura-tions, is an important technological response tothree distinct challenges to the transportationsystem: urban air quality, oil security, and globalwarming (Johansson et al. 1996; Sperling 1996).Urban air quality is a critical public health prob-lem throughout the world, exacerbated, in muchof the developing world, by fast-growing urbanpopulations. Oil security is an international geo-political problem rooted in the enduring fact thatthe Persian Gulf region has a large fraction of theworld’s lowest-cost oil reserves. Global warmingis a deep challenge to a global energy systemwhere roughly three-fourths of primary energycomes from fossil fuels.

In many regions of the world the objective ofimproving local air pollution is paramount. Cali-fornia is one of these regions, and its initiativeshave driven the development of an electric ve-hicle of short range, with a battery as the exclu-sive power source.6 One version of thebattery-powered vehicle uses a large lead battery:this is the only lead battery for advanced ve-hicles envisioned in the LRHM analysis. A sec-ond lead battery has now come into view,however, with potentially greater promise as acommercially effective response to air pollution,oil security, and global warming: the lead batteryin the role of peak-power device for hybrid elec-tric vehicles.

The Battery-Powered Vehicle

The short-range battery-powered electric ve-hicle has been brought to market in response, es-pecially, to regulatory pressure from the state ofCalifornia on the major automobile companiesto sell a zero-emission vehicle. California’s ZEVmandate requires, for each automobile company,that at least 10% of vehicle sales in California beZEVs by 2003.7 The ZEV mandate continues along tradition of regulatory independence by the

state of California, which, beginning in the1960s, has repeatedly tightened, ahead of thefederal government, the limits on emissions ofspecific combustion products from new vehiclessold there (Calvert et al. 1993).

The battery-powered car confronts several se-vere challenges today. Its range, the distance itcan travel on a fully charged battery before thebattery must be recharged, is currently less than150 km (roughly 100 miles), far below the rangeof today’s gasoline-powered cars on the road.8

The time required for battery recharging consid-erably exceeds the time required for filling agasoline tank. And the production cost appearsto be considerably greater than the productioncost of the gasoline-powered vehicle. Principallyfor these reasons, the battery-powered car is ex-pected to be competitive only in niche markets.

Electric cars running on other kinds of batter-ies are now entering production. Beginning withtheir 1997 models, Toyota and Honda are plan-ning to sell, in California and elsewhere, a fewhundred electric cars using nickel/metal-hydridebatteries, and Nissan is entering these same mar-kets with a car using a lithium-ion battery. Both ofthese batteries promise to give an electric car atleast twice the range envisioned for a car with alead battery. Nonetheless, in these same automo-tive markets, the higher-volume car General Mo-tors has chosen to introduce, the EV-1, has a leadbattery. Apparently, the cost advantages of thelead battery were judged by General Motors todominate the disadvantages of low energy density.

When a lead battery is removed from an elec-tric car, generally because the battery can nolonger go through a cycle of discharge and re-charge effectively, the lead in that battery willenter the highly developed recycling system al-ready in place for managing the SLI battery. Be-cause of its size, it is hard to imagine it beingabandoned; recovery rates will be close to 100%.Also, it “will be large enough to warrant consid-eration of disassembly and material segregation(manual or automated) as the first step in recy-cling,” which should simplify handling (Gainesand Singh 1995). By contrast, the recycling sys-tem for the nickel (and other metals) in thenickel/metal-hydride battery is just emerging, andthe recycling system for the materials in thelithium-ion battery does not yet exist (California



Air Resources Board 1995). Serious consequencesfor public health and the environment may ariseif the management of the materials in these newerbatteries is done poorly: the risks are relativelyunclear. There are few elements in the periodictable whose toxicity has been as well studied asthat of lead (National Research Council 1993;Castellino, Castellino, and Sannolo 1995).

The automobile industry has already begunto market range-extending hybrid vehicles thatrespond both to community concern about ur-ban air quality and to consumer concern for ve-hicle range. Such vehicles use battery power forin-city driving and a combustion engine forlong-distance travel. The lead battery for such ahybrid vehicle would be nearly as large as thelead battery for a vehicle powered only by a bat-tery. Both the all-lead-battery electric car andthe range-extending, lead-battery hybrid couldbe manufactured for decades.

The Peak-Power Hybrid Vehicle

California’s ZEV mandate was designed tostimulate the development of new kinds of ve-hicles that reduce local air pollution, but it re-sulted in nearly all engineering initiative beingdirected toward a single technological response,the short-range battery-powered vehicle. A sub-sequent 1994 U.S. federal government initiative,the Partnership for a New Generation of Vehicles(PNGV) program, is redressing the balance. Acollaborative industry-government effort, thePNGV program has focused less on the challengeof air quality and more on the challenges of oilsecurity and global warming. It has set the goal oftripling the fuel economy of the automobile by2004, relative to a 1994 automobile with compa-rable performance, size, safety, and emissions.The most promising technological response ap-pears to be the peak-power hybrid car (NationalResearch Council 1996).

A quite general argument provides the ratio-nale for peak-power hybrid cars. The task of driv-ing involves short periods of time, such as whenpassing another vehicle or climbing a steep hill,when pulses of supplementary power are needed,and long periods of routine driving when base-load power is adequate (Ross 1994). A peak-power hybrid vehicle is any vehicle that uses

separate onboard systems to produce peak powerand base-load power. (The peak-power hybrid isan entirely different hybrid from the range-ex-tending hybrid discussed above.) A peak-powerhybrid vehicle should be able to achieve greaterenergy efficiency (higher fuel economy) andlower emissions than a vehicle using only oneenergy system, for three reasons: (1) the base-load system can be designed to operate always atnearly optimal conditions; (2) the peak-powersystem can be light in weight, because it can berepeatedly recharged by the base-load system;and (3) the peak-power device can improve en-ergy efficiency by doubling as an energy storagedevice that recovers the energy of braking.

Batteries (as well as flywheels and ultracapa-citors) are well matched to the task of providingpeak power for hybrids, because they can be re-peatedly recharged on board (MacKenzie 1994;Illman 1994; Sperling 1995; Office of TechnologyAssessment 1995; National Research Council1996). Only recently, after decades of concentra-tion on the objective of range, has battery re-search addressed the objective of peak power. Ofspecial relevance to the argument in this article,the first commercially interesting peak-powerbatteries emerging from this research are lead-acid batteries (Juergens and Nelson 1995; Nelson1996; Keating, Schroeder, and Nelson 1996). Asin the competition among batteries for battery-only electric vehicles, the cost advantage enjoyedby the lead battery will improve its prospects inthe competition for providing peak power. Apeak-power battery would have much less leadthan a battery providing range.

The base-load partner in a peak-power hybridvehicle must give the vehicle good range andconvenient refueling. Generally, these objec-tives are met by storing the fuel on board in atank. Two distinct peak-power hybrid vehiclesinvolving a battery for peak power are in view: acombustion-engine/battery hybrid and a fuel-cell/battery hybrid (National Research Council1996).9

The peak-power hybrid using a combustionengine for base-load power and a battery forpeak power will use onboard fossil fuel both topower the car and to recharge the battery,thereby not requiring electricity generated at aseparate power plant. Candidate base-load part-



ners in the combustion-engine/battery hybridinclude the gasoline engine, the diesel engine,the stirling engine, and the gas-turbine engine.These hybrids do not qualify as ZEVs, but theymay be the best candidates for meeting thePNGV program’s goals (National ResearchCouncil 1996), and they may be impressiveoverall, when judged against the joint objectivesof local air quality, oil security, and global warm-ing (Ross and Wu 1995). Prototype combustion-engine/battery peak-power hybrids are nowbeing designed.10

Although the peak-power hybrid using afuel cell for base-load power and a battery forpeak power lies somewhat further in the future,it may be even more impressive. It promiseszero or near-zero emissions; high energy effi-ciency; and advantages in addressing oil secu-rity, because the fuel for the fuel cell can be aproduct derived from a fossil fuel other thanpetroleum or from a nonfossil energy sourcesuch as wood chips (Willliams 1994).

The fuel cell derives its power from the elec-trochemical oxidation, instead of the combus-tion, of a fuel on board. In the prototypefuel-cell vehicles being tested today, the fuel ishydrogen, and the hydrogen combines electro-chemically with the oxygen in air to make water.The underlying chemical reaction is not an ob-stacle to achieving long range.11 And the end ofa fuel cell’s life cycle may not be complicated ei-ther. Today’s most promising contender fortransportation applications, the proton-ex-change-membrane (PEM) fuel cell (Prater1994), uses carbon electrodes and a platinumcatalyst, as well as casing and tubing that do notrequire exotic materials. Safe managementseems possible.

Electric and hybrid vehicles are being en-couraged by strong industries. The electric utili-ties see large new markets with potentiallyattractive load characteristics, and aerospaceand other high-technology companies hope tomanufacture advanced batteries, fuel cells, andrelated components. However, the industrialsystem delivering transportation today, based onpetroleum and on vehicles where both base-loadand peak power are provided by a single largeinternal combustion engine, will not be easilyabandoned. Indeed, it has already evolved con-

siderably to improve fuel economy and to reduceemissions, and it has the potential to evolve fur-ther. The same approaches that brought pastimprovements will bring future improvements;these include streamlining and lowering theweight of the vehicle, improving the control offuel injection, incorporating better catalytictreatment of the exhaust, and modifying the fuel(Office of Technology Assessment 1991;DeCicco and Ross 1994; Ross 1994). Time willtell whether dramatically different vehicles cancapture a large market share from vehicles thatcontinue to be improved incrementally.

Environmental and HealthImpacts of Lead in Gasolineand Batteries

Health Consequences of Lead Exposure

The dangers of exposure to high levels of leadhave been understood for centuries. Beginning inthe 1970s, however, epidemiological studies re-ported adverse effects on child development atwhat had previously been considered low andnormal levels of lead exposure, down to a bloodlead concentration of 10 micrograms per decil-iter. (The standard measure of human exposureto lead is the concentration of lead in blood, ex-pressed in the United States as micrograms perdeciliter, or µg/dL, a deciliter being one-tenth ofa liter.12) A recent U.S. National Research Coun-cil (1993, 93) review concluded: “The weight ofevidence gathered during the 1980s clearly sup-ports the conclusion that the central and periph-eral nervous systems of both children and adultsare demonstrably affected by lead at exposuresformerly thought to be well within the safe range.In children, blood lead concentrations around 10µg/dL are associated with disturbances in earlyphysical and mental growth and in later intellec-tual functioning and academic achievement.” Asa result of these studies, in 1991, the U.S. Cen-ters for Disease Control reduced its thresholddefinition of dangerous levels of lead in children’sblood from 25 µg/dL to 10 µg/dL (U.S. Depart-ment of Health and Human Services 1991a).

The concentration of lead in blood is generallyconsidered to be a measure only of recent lead ex-posure, because over a period of 20 to 30 days lead



B)

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Figure 1 Histograms of blood lead levels in two national samples, the National Health and NutritionExamination Surveys known as NHANES II and NHANES III, roughly a decade apart. The data inNHANES II are from 1976 to 1980 and the data in NHANES III are from 1988 to 1991. Both the fullsamples (A, B) and the subsamples of children aged 1 to 5 (C, D) are shown. The units of blood lead levelare given in both micromoles per liter and micrograms per deciliter, two units which differ by a factor of20.7 (one-tenth the atomic weight of lead). Source: Pirkle et al. (1994).



is deposited to bone, where it accumulatesthroughout life, at least until the age of 50 to 60.But lead in bone is not inert. Bone lead remains inequilibrium with blood lead and, especially inpeople with high past exposures, lead released frombone can make a significant contribution to bloodlead concentrations. Moreover, the release of leadfrom bone to the bloodstream increases duringmenopause, pregnancy, and old age. Maternalblood lead is passed to the fetus, and maternalblood lead levels in the 10 µg/dL range have beenassociated with adverse effects on fetal and infantdevelopment (Silbergeld, Schwartz, and Mahaffey1988; National Research Council 1993).

The average blood lead concentrations in theU.S. population have been remarkably welldocumented. In 1976 to 1980 and 1988 to 1991,the National Center for Health Statistics andthe Centers for Disease Control conducted Na-tional Health and Nutrition Examination Sur-veys, which included measurements of lead inblood. The two studies, known, respectively, asNHANES II (Annest et al. 1983) andNHANES III (Brody et al. 1994), allow closecomparison (Pirkle 1994).

Figure 1 compares the distributions of bloodlead levels in two representative samples fromthe NHANES studies, each consisting ofroughly 10,000 people. Figure 1 also comparesthe distributions just for children between oneand five years old, from subsamples of roughly2,000 children. In NHANES II the mean bloodlead level for the whole sample was 12.8 µg/dL,and the mean for children aged one to five was15.0 µg/dL. (These are arithmetic means.) Butin NHANES III these means had plummeted, ineach case by more than a factor of four, to 2.8 µg/dL and 3.6 µg/dL, respectively. Focusing just onthe children aged one to five with blood leadlevels below 10 µg/dL, the change is particularlystriking: at the time of NHANES II, only 12% ofthe children in this age group were in this cat-egory, whereas, at the time of NHANES III, thepercentage had grown to 91% (Pirkle 1994).

In the case of lead, the consequences for hu-man health are so disturbing that the comple-mentary impacts on nonhuman species andecosystems have received much less attention.Many details of the biological uptake and me-tabolism of lead still need to be worked out to

assess the vulnerability of nonhuman speciesand ecosystems to lead releases. An unmistak-able effect, however, has been the damage tomany species of birds by ingestion of lead shot:waterfowl eat lead shot that they find scatteredthroughout their habitats, often resulting inacute poisoning and mass die-offs; bald eaglesand other birds of prey eat animals that havebeen shot but not retrieved by hunters, with theresult that lead poisoning has become a signifi-cant cause of death for bald eagles. In response,several countries have banned lead shot fromwaterfowl hunting (Pain 1992).

The ecological impact of lead shot is muchgreater than other solid lead, because waterfowllike to eat lead shot. Children can have particu-larly high exposures to lead in dust, because ofhand-to-mouth activity. Lead crystal can resultin high lead exposures, because people storewines in lead crystal decanters. To understandthe consequences of lead product use and leademissions, industrial ecology must take into ac-count these and many other animal and humanbehaviors. In the remainder of this section weexplore in some detail the health consequencesof the principal uses of lead in cars: lead in gaso-line and lead in batteries.

Lead in Gasoline

Lead is added to gasoline (usually as tetraethyllead) to raise its octane. A higher octane permitsthe combustion of a spark-ignited fuel-air mix-ture to occur smoothly, without knock. Knock isa phenomenon where some disorganized combus-tion occurs in the engine after the spark, ahead ofthe main flame. It can lead to a shortening of en-gine life.

Today, the strategy of enhancing octane withlead additives is being abandoned worldwide infavor of other routes to octane enhancement.One benefit of this change is reduced humanexposures to lead. But there is a second benefitto public health as well: abandoning lead addi-tives makes possible the achievement of strin-gent tailpipe emissions standards for carbonmonoxide, volatile organic compounds, and ni-trogen oxides. The second benefit arises becausetoday’s most cost-effective technology forachieving these stringent emissions standards,



chosen worldwide, incorporates a three-waycatalytic converter with a platinum catalyst, andlead in gasoline destroys the catalyst. Both ben-efits have set one country after another on thepath to lead-free gasoline.

The octane level of gasoline can be raisedwithout resorting to lead additives. Various in-vestments at the oil refinery can increase the oc-tane level by increasing the fractions of highlybranched molecules, oxygenated molecules, orunsaturated ring compounds (aromatics). To besure, each of these fractions has its own complexconsequences for pollutant emissions and forpublic health. Still another approach to octaneenhancement involves adding manganese com-pounds to the fuel. The health effects of manga-nese are less well studied than the health effectsof lead, and this strategy is particularly controver-sial (Solomon, Herman, and Silbergeld 1996).

Figure 2 shows 50 years of global consumptionof lead in gasoline additives. The data reveal asharp peak, at almost 400,000 metric tons, in theearly 1970s. By 1993, global consumption of leadin gasoline additives had fallen to 70,000 metrictons. Figure 2 also shows the United States domi-nating lead global consumption until recentyears. Today, the United States and several othercountries have almost completely eliminated the

use of lead in gasoline, and many countries are inthe process of phasing it out (Organization forEconomic Cooperation and Development 1993;Thomas 1995). But the use of lead in the “rest ofworld,” largely developing countries, remainedalmost constant from 1970 to 1993.

The NHANES II study of U.S. populationblood lead levels was carried out between 1976and 1980, a time of major reduction in gasolinelead additives in the United States. TheNHANES II data made possible an analysis ofthe relation between U.S. population blood leadlevels and total lead used in U.S. gasoline. Com-paring data on U.S. consumption of lead gaso-line additives for nine six-month intervalsbetween 1976 and 1980 with NHANES II bloodlead data revealed that blood lead concentrationwas highly correlated with gasoline lead use(0.93 correlation coefficient). During thoseyears the average blood lead level dropped byabout one-third, and the rate of use of lead ingasoline production dropped by about one-half(Annest et al. 1983).

Air lead levels also fell sharply when gasolinelead use was reduced. The emissions inventoriesof the U.S. Environmental Protection Agencyshow that leaded gasoline was by far the largestsource of lead air emissions in the United States

Figure 2 A 50-year view of global production and consumption of lead in gasoline additives. Mainsources: International Lead and Zinc Study Group (1992); Octel (1970–1992).

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during the 1970s and 1980s (U.S. Environmen-tal Protection Agency 1993). As lead in gasolinewas reduced, U.S. air lead levels fell correspond-ingly. In 1979 the average concentration of leadin urban air was 0.8 µg/m3, and it was less than0.1 µg/m3 in 1988 (U.S. Environmental Protec-tion Agency 1990).13

Studies of the effect of reduced use of lead ingasoline on population blood lead levels havebeen conducted in several other countries. In allcases, decreased use of lead in gasoline results indecreased blood lead levels. In three separate Eu-ropean studies, the average lead concentration inblood fell by 6 to 9 µg/dL when the lead concen-tration in gasoline was reduced from about 0.40to 0.15 g/L. These studies—in Turin, Italy (Bonoet al. 1995), in Belgium (Ducoffre, Claeys, andBruaux 1990), and in Tarragona Province, Spain(Schuhmacher et al. 1996)—were conductedover intervals of four to eight years. They alsomeasured substantial reductions in lead concen-trations in air.

Although the drop in blood lead level ishighly correlated with the drop in use of lead ingasoline, some of the decline may be attributableto reductions in other sources of lead exposure,including lead solder in canned foods and lead inpaint (Thomas 1995). In Christchurch, NewZealand, a drop in average blood lead concentra-tion of about 7 µg/dL over about a four-year in-terval was seen, even though the concentrationof lead in gasoline remained constant at 0.84 g/Land the volume of gasoline sold hardly changed(Hinton et al. 1986). The authors of the NewZealand study attributed the decrease in bloodlead levels to “the fall in dietary and domesticand industrial environmental sources of lead andincreasing public awareness of its effects.”

Insight into the contribution of leaded gaso-line to blood lead levels can be obtained with thehelp of isotopic techniques. The stable isotopesof lead (particularly 204, 206, 207, and 208) arepresent in different ratios in different lead ores. Ifthe lead used in gasoline has isotopic ratios suffi-ciently different from the ratios for other sourcesof lead exposure, then by measuring the isotopicratios of lead in the blood, gasoline, and othersources, the fraction resulting from lead in gaso-line can be determined. For a 1970s study inTurin, Italy, the lead used in gasoline was

switched to a lead with isotopic ratios signifi-cantly different from the other local sources.(The switchover was phased in over a period of20 months, and the isotopically distinct gasolineremained for an additional 31 months.) Before,during, and after the switch, lead isotope ratioswere measured in blood and air. The resultsshowed that the portion of blood lead attribut-able to gasoline emissions (except for emissionsbefore the isotopically distinct gasoline was in-troduced) was approximately 5 µg/dL out ofabout 20 µg/dL (Faccetti 1984, U.S. Environ-mental Protection Agency 1983).

The isotope technique provides only a lowerbound to the contribution of gasoline lead toblood lead. At a later date (as mentioned above),between 1985/86 and 1993/94, gasoline lead con-centrations in Turin were reduced from 0.40 g/Lto 0.15 g/L, and average blood levels droppedfrom 15.1 µg/dL to 6.4 µg/dL (Bono et al. 1995),a larger drop than the isotope study would havepredicted. Part of the observed difference in theblood lead levels before and after the reduction ofthe lead concentration in gasoline may havebeen a result of reduced exposure to other sourcesof lead. And part may have been a result of anunderestimate of the portion of blood lead attrib-utable to gasoline in the isotope experiment: leadfrom gasoline used before the switchover may stillhave been stored in bone and may not have fullyequilibrated with lead in blood (Schwartz 1996),and lead from gasoline used before the switchovermay have been stored in soils and dust and in-haled or ingested after the switchover.

The evidence of these and other studies hasled to widespread recognition of leaded gasolineas a significant contributor to human lead expo-sure. Where lead has been eliminated from gaso-line, it is properly viewed as a major achievement.

Lead in Batteries

The ratio of secondary (recycling) lead pro-duction to primary lead production has in-creased nearly continuously in the United Statesfor the past 80 years. Figure 3 shows the detailsof production during that period, as well as leadconsumption, by category of lead product, forthe past 30 years. Primary lead production hasfallen steadily since 1970, along with the total



use of dissipative lead products (gasoline addi-tives, oxides, and ammunition). Secondary leadproduction in the same period closely tracks pro-duction of batteries.

The dominance of batteries and battery recy-cling in the lead flows through the U.S. economyis seen in figure 4, which shows sources, products,and fates. The total annual U.S. lead consump-tion (averaged over 1993 and 1994), about 1.4million metric tons, is dominated by 910,000 met-ric tons of secondary (recycled) production, therest being primary production and imports. Bat-teries are the main product, consuming 1,180thousand metric tons.

Although recycling rates are not as high as inthe United States, the global pattern of lead useand recycling is similar. In 1990, global lead pro-duction, 5.9 million metric tons, is the sum ofabout 3.3 million metric tons of primary produc-tion and about 2.6 million metric tons of sec-ondary production. The total production forbatteries, 3.7 million metric tons, is more than60% of production for all products (Thomas andSpiro 1994).

The U.S. battery industry estimates that, an-nually from 1990 to 1994, from 93% to 98% oflead available for recycling was actually recycled.“Available” lead is estimated from the production

Figure 3 History of U.S. lead production and consumption. Production is in three categories, shownadditively: primary, secondary (recycled), and net imported lead. Consumption is in five categories, also shownadditively: batteries; gasoline additives; oxides for paints, glass, etc.; ammunition; and other products. Note thatgasoline additives, oxides, and ammunition are largely dissipative (most of the lead leaves the industrialsystem with use), and that since 1970 the drop in primary production has approximately matched the dropin total consumption for dissipative use. Note also that secondary production climbs with the increasedconsumption of lead batteries. Sources: U.S. Bureau of Mines (1993, 1995); U.S. Department of Commerce(1975, 603); Woodbury, Edelstein, and Jasinski (1993).

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of batteries for transportation in previous years,taking into account exports and imports of bat-teries as well as battery lead in scrap (BatteryCouncil International 1995). The Battery Coun-cil International’s methodology can be illustratedfor 1994, when the “recycling rate” was 98%. Thenumerator, 834,000 metric tons, is simply themass of lead arriving in batteries at secondarysmelters in 1994, derived from questionnairessent to the 11 companies that own all the U.S.secondary smelters. The denominator, 849,000metric tons, is an estimate of the domestic supplyof lead in batteries that should have becomeavailable as previously produced batteriesreached the end of their useful life, taking intoaccount exports and imports. Exports and im-ports are in three categories: lead in new batter-ies (both batteries as separate products andbatteries in vehicles of the appropriate year), leadin worn-out batteries, and lead in waste and scrapderived from batteries.14

Figure 4 shows an expanding stock of leadwithin the U.S. industrial system. Entering thesystem from mineral extraction (bottom left) ismore lead than leaves the system via disposaland export (bottom right) and recycling waste(top right). The same expansion is displayed inthe leftward tapering (trapezoidal) shape at topcenter, which reflects the time lag between pro-duction and eventual recycling of batteries (onaverage, about three years).

Figure 4 (top left) shows 7,000 metric tons oflead leaving the U.S. industrial system as recy-cling wastes. These recycling wastes are reportedin the Toxic Release Inventory as land disposaland off-site transfer of lead from 15 secondary leadsmelters (U.S. Environmental Protection Agency1994a). Given that the total production in 1994at all smelters was about 910,000 metric tons(U.S. Bureau of Mines 1994), the recycling wastesare about 0.8% of secondary production, and thusare in agreement with the LRHM estimate of 1%.

Almost all recycling waste is solid waste. Pastpractices of the lead-battery manufacturing andrecycling industry have left the United Stateswith over 50 lead-contaminated Superfund sites,characterized by high concentrations of lead inthe soil and lead in groundwater or surface water(Roque 1995). Today, the Resource Conserva-tion and Recovery Act (RCRA) regulates waste

disposal from secondary lead recycling and bat-tery manufacture in the United States. To con-form to RCRA regulations, the slag that is thesolid aggregate remaining from the smelting pro-cess can be treated to reduce the ability of leadto be leached. In a common method of treat-ment, called “stabilization,” leachability is re-duced by mixing the waste with portland cement(Lebo 1996).

Figure 4 also shows that about 50,000 metrictons of lead are in batteries that are not recycledbut remain in the United States. Some of thesebatteries end up in landfills, where leaching canresult in lead moving into groundwater or surfacewater. As of the mid-1980s, battery lead was esti-mated to represent 65% of the total lead in mu-nicipal waste landfills (Franklin Associates1988). The concentration of lead in leachatefrom municipal waste landfills has been mea-sured, and has been found to be as high as 1,600micrograms of lead per liter of leachate (µg/L) forpre-1980 landfills, and as high as 150 µg/L forpost-1980 landfills. The U.S. EnvironmentalProtection Agency presents a worst case scenario,where this leachate is diluted by a factor of only100 by groundwater before reaching well-water(U.S. Environmental Protection Agency 1991).The resulting maximum lead concentration indrinking water from a pre-1980 landfill, 16 µg/L,can be compared with the current U.S. SafeDrinking Water Act goal to reduce lead concen-trations in drinking water to below 15 µg/L.

Some unrecycled batteries do not go to land-fills, but are discarded directly on the land (inbackyards, for example). Although lead is quiteimmobile in soil and tends to be adsorbed by soilparticles, the lead in a battery discarded on theland is relatively mobile; this is because up to halfof the lead in a battery is in the form of a paste oflead oxide and lead sulfate, and because the acidelectrolyte can enhance lead migration in soil(U.S. EPA 1991).

Figure 5 summarizes the record from 1975 to1990 for the United States, showing the con-sumption of lead in gasoline additives and bat-teries, along with the average blood lead levelsin the population. The use of lead in batterieshas increased, although not steadily, and lead inautomotive gasoline has disappeared, whilepopulation blood lead levels have plummeted.



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Hazards to the communities near secondarysmelters and the potential for improvementToday, human health and the environment

are adversely affected in communities near manysecondary smelters. Some of the smelters are lo-cated in developing countries, and many ofthese smelters receive a significant fraction oftheir lead from industrialized countries, largelyas scrap. Many of the smelters in developingcountries are characterized by very large envi-ronmental lead emissions, documented by highlead concentrations measured in river and marshsediments and in soils (Greenpeace 1994).

Results of numerous studies document thatpeople sustain marked increases in blood leadlevels when they live near secondary lead smelt-ers and other stationary lead sources (ATSDR1988). Consider two U.S. and three non-U.S.studies:

A 1972 study of an Alabama smelterfound that 30 of 37 employees had bloodlead levels exceeding 80 µg/dL. Animalson nearby pasture had died, and lead lev-els in blood, milk, and hair of large andsmall animals were elevated. (Levine et al.1976)

A 1982 study of two secondary smelters inDallas, Texas, compared 830 preschool(aged one through five) black children liv-ing within one-half mile of these smelterswith 221 comparable children living in areference area far from the smelter. Thechildren living near one smelter had aver-age blood lead levels of 20.1 µg/dL, and thechildren living near the other smelter hadaverage blood lead levels of 15.8 µg/dL.These levels can be compared to those of

Figure 5 Annual U.S. lead use in gasoline and batteries and U.S. population blood lead levels from 1975to 1990. Battery data are from U.S. Bureau of Mines 1993 and 1995. Gasoline data are from Nriagu 1990.Both the battery and the gasoline data are referenced to the x-axis: they are not shown additively. Bloodlead data are from NHANES-II (Annest et al. 1983) and NHANES-III (Pirkle et al. 1994). NHANES-II dataare 28-day averages from February 1976 to February 1980 (Annest et al. 1983, figure 1). The singleNHANES-III blood-lead data point at 1990 is an average for 1988 to 1991. The dotted line connecting theNHANES II time series with the single NHANES III data point is a only a guide to the eye: there are nointermediate data points.

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children in low- and high-traffic areas farfrom the smelters, 13.2 and 14.6 µg/dL, re-spectively. (Carra 1984)

A 1973 study of two smelters in Torontofound that 30 percent of the children liv-ing near one smelter and 13% of the chil-dren living near the other smelter hadblood lead levels exceeding 40 µg/dL.(Roberts et al. 1974)

A study of a secondary lead smelter in Tai-wan found that 22 of 36 children in a kin-dergarten near the smelter had blood leadlevels exceeding 15 µg/dL, in comparisonwith 1 out of 83 children in a kindergartenfar from the smelter. (Wang et al. 1992)

In the Yugoslavian city of Kosovska Mitro-vica, located between a lead smelter to thenorth and a battery factory to the south,35% of children had blood lead levels be-tween 50 and 69 µg/dL in 1980, and an ad-ditional 12% had blood lead levels above70 µg/dL. Mean annual air lead concentra-tions ranged from 21.3 to 29.2 µg/m3 in1980. (Popovac et al. 1982)

As a result of investments in pollution controland materials management, the adverse environ-mental impacts of some secondary smelters onnearby communities are becoming much less seri-ous. A recent study at a secondary lead smelter inCalifornia retrofitted with state-of-the-art pollu-tion control systems found no statistically signifi-cant impact on the blood lead levels of thechildren in a nearby community. The study exam-ined blood lead levels and lead in the householdenvironment of children between ages 1 and 5;data were obtained from two communities, thenearby community and a control, with a samplesize of 122 children in each community. The aver-age blood lead level in the exposed and controlgroup were nearly the same, 3.8 and 3.5 µg/dL, re-spectively (Wohl, Dominguez, and Flessel 1996).15

This improvement is reflected in air emis-sions factors for secondary smelters (total mass ofair emissions divided by total lead production)that have decreased substantially in recent yearsin the United States. The LRHM analysis assertsthat the air emissions factor is at least 0.02%, avalue that was derived by the U.S. Environmen-

tal Protection Agency from data reported for its1987 Toxic Release Inventory (Roque 1995).But current reports from secondary smelters in-dicate air lead emissions that are an order ofmagnitude lower. The California Air EmissionsBoard, for example, routinely uses an air emis-sions factor of 0.002%.

The CARB air emissions factor turns out to bebased only on a single three-day “source test”conducted at CARB’s behest in November 1990,at a large secondary smelter owned by GNB inVernon, California (McLaughlin 1996).16 Con-siderable evidence confirms CARB’s air emis-sions factor as characteristic of many secondarysmelters today. We have calculated air emissionsfactors for 17 of the 18 secondary lead smelters inthe United States, by combining Toxic ReleaseInventory data from 1994 with information onthe capacities of U.S. secondary lead smelters.The data are presented as a histogram in figure 6.The production-weighted average air emissionsfactor (including both fugitive and point emis-sions) is 0.006 percent (a total of 57 metric tonsof air emissions from the secondary production of910,000 metric tons). The distribution of airemissions factors in figure 6 is consistent with theair emissions factors for two California smelters(Steele and Allen 1996). It is also consistent withthe 0.001 percent air emissions factor reported byBoliden Bergsoe, a firm that owns a secondarysmelter in Landskrona, Sweden (Karlsson 1996).Even lower air emissions factors are reported in asummary of a confidential industry survey (Elec-tric Power Research Institute 1993).

The average air emissions factor for secondarysmelters has fallen in recent years because somesmelters have invested in pollution control tomeet tighter regulations and others have gone outof business. In 1995, the U.S. Environmental Pro-tection Agency established limits on air emissionsfrom secondary lead smelters; as these limits comeinto effect, air emissions factors can be expected tofall further.

Childhood blood lead screening is now routinethroughout the United States. Given the con-tinuing progress in reducing lead emissions re-ported by the companies owning secondary leadsmelters, these companies should be challenged todemonstrate that blood lead levels in nearby com-munities are indistinguishable from those in simi-



lar communities far from smelters. The collectionand publication of blood lead levels in communi-ties near all secondary lead smelters would go along way toward clarifying the extent of lead ex-posure from lead-battery recycling.

Occupational exposure: the hardestchallenge to clean recyclingA complete assessment of the level of worker

exposure associated with U.S. battery recyclingmust take into account that some of the lead inU.S. batteries is exported as a component of leadscrap, and that some of this lead is processed insmelters in the developing countries whereworker exposures are very high (Greenpeace1994).

In the United States, the 1978 lead standardsof the Occupational Safety and Health Admin-istration (OSHA) have had an important role incontrolling occupational lead exposures(Silbergeld, Schwartz, and Mahaffey 1991). Thestandards require removal of workers to a lead-free area if the blood lead level exceeds 50 µg/dLfor six months or more, and immediate removalif the blood lead level exceeds 60 µg/dL, untilsuch time as the blood lead level is reduced to 40µg/dL or less. Pressure to revise these standards is

increasing (Spurgeon 1994). In 1991 the U.S.Public Health Service declared a goal of elimi-nating occupational lead exposures exceeding 25µg/dL by the year 2000 (U.S. Department ofHealth and Human Services 1991b). Even at 25µg/dL, pregnant female workers will be at risk forpassing lead directly to developing fetuses; bloodlead levels above 10 µg/dL in women can resultin fetal exposure in excess of the Centers for Dis-ease Control recommendations.

Instances of high worker exposure continueto surface in the United States. A 1991 investi-gation of an Alabama battery reclamation facil-ity (where batteries are cut open and the leadand plastic are sent to other plants for furtherprocessing) found that 14 of 15 workers hadblood lead levels exceeding 50 µg/dL. The neigh-boring community was also affected: 12 of 16employee children had blood lead levels exceed-ing 10 µg/dL, with three children having levelsgreater than 40 µg/dL. A survey of 11 adults and5 children (aged 6 to 17) living within one blockof the plant found average blood lead levels of11.6 µg/dL and 9.8 µg/dL, respectively. In re-sponse to this information, OSHA declared thefacility an “imminent danger,” and all workerswere removed from their jobs until their blood

Figure 6 Histogram of thevalues of the total air emissionsfactors for 17 U.S. secondary leadsmelters in 1994. The emissionfactor for each smelter is its total(stack plus fugitive) air emissions,as reported in the U.S. Environ-mental Protection Agency’s 1994Toxic Release Inventory, dividedby the midpoint of its estimatedcapacity. Each bin of the histogramis an approximately factor-of-three interval. Sources: U.S.Environmental Protection Agency(1994a, 1994b).

0.0003-0.001%

0.001-0.003%

0.003-0.01%

0.01-0.03%

0

1

2

3

4

5

6

7

8

9

10

Smelter Total Air Emissions Factor

Num

ber

of S

mel

ters



lead levels declined to 40 µg/dL. The magnitudeof the health and safety fines ($1.2 million) con-tributed to the owner’s decision to close the facil-ity (Gittleman et al. 1994).

Reducing worker blood lead levels to those ofthe general population is a task of unknown dif-ficulty. The extent of worker exposure today isrevealed in data collected by Battery Council In-ternational, a trade organization that collectsdata on worker blood lead levels in U.S. second-ary smelters and battery manufacturing plants.In the first three months of 1996 about 6% ofworkers in secondary smelters had levels exceed-ing 40 µg/dL and 56% had levels exceeding 20µg/dL; the percentages for battery plants were2.5% and 44%, respectively (Battery CouncilInternational 1996).17

Conclusions

The LRHM analysis has been productive, be-cause it has called attention to the prospect thatserious negative environmental impacts couldresult from the use of large amounts of lead inthe power sources of electric vehicles. But as aguide to how to think about that prospect, theLRHM analysis has three serious shortcomings.First, as a technology assessment, it is oversim-plified. It gives little weight to the ferment inautomotive engineering and, thereby, underesti-mates what is at stake in keeping open a multi-plicity of technological options. Second, as a riskassessment, it is misleading. It fails to identifyseveral critical environmental and public healthhazards associated with relatively small massflows, thereby demonstrating the perils of per-forming a mass-flow analysis without an accom-panying hazard analysis. Third, as a guide toindustrial initiative and public policy, it is in-complete. It fails even to consider the possibilitythat the lead-battery industry could implement amodel clean recycling system.

This is a period of great fluidity in automotiveengineering. Multiple options for providing theenergy for vehicles are being explored, and eachnew capability has implications for several op-tions at once. The battery-powered car could notpenetrate even niche markets at this time, if itdid not incorporate innovations related to fueleconomy and the management of electricity on

board—innovations that have broad implica-tions affecting the rates of progress for other ve-hicle concepts. The research-and-developmentprocess would be proceeding more slowly, if stateand national governments were not actively pro-moting electric and hybrid vehicles through themandating of prototype development and pilot-scale marketing.

An important argument against thwarting thedevelopment of the lead battery for electric ve-hicles is that the lead battery may have a second,entirely different, and potentially more impor-tant assignment than the assignment envisionedin the LRHM analysis. In addition to providingstand-alone power for short-range vehicles, thelead battery may provide peak power in severalkinds of hybrid vehicles. These peak-power hy-brids may be particularly suited to address, simul-taneously, urban air quality, oil security, andglobal warming. The fuel-cell/battery peak-power hybrid, in particular, may expand optionsfor the global transportation system by facilitat-ing the introduction of renewable fuels.

When a social experiment is dangerous to thepublic even at a small scale, it is important that itbe deterred. But there is another class of experi-ments, of which the pilot programs for electricvehicles are an example, where the experimentitself presents negligible risks, but full-scaleimplementation has the potential for seriousharm. For this class of experiments, there may bea large societal and environmental cost in sup-pressing the experiment. Freeman Dyson captureswhat is at stake in an essay entitled, “The Cost ofSaying No”: “It is not enough to count the hid-den costs of saying yes to new enterprises. Wemust also learn to count the hidden costs of say-ing no. . . . It often happens in technological de-velopment that one design turns out to be notmerely better but enormously better than its com-petitors, for reasons that could not have been pre-dicted in advance. There is no way to find thebest design except to try out as many designs aspossible and discard the failures” (Dyson 1975).

Because the LRHM analysis focuses on massflows rather than on hazards, it is poorlymatched to the task of identifying a recyclingsystem’s most important environmental andpublic health consequences. Often, on a massbasis, the principal emissions are in the form of



bulk solids, such as slags; yet, several muchsmaller mass transfers have far greater health im-pacts. Meriting detailed and sustained attentionare exposures to workers and to people in neigh-boring communities.

A mass balance can be indispensable, how-ever, in accounting for consumer products thatescape the recycling system; in the case ofunrecycled batteries, the health and environ-mental impacts are still largely unexplored. Anda mass balance can provide detailed informationabout imports and exports; here an important is-sue is the export of scrap containing lead fromused batteries to countries where environmentalcontrols are weak.

Generalizing, a proper risk assessment mustcombine mass-flow analysis with hazard analy-sis. It must fully explore the impacts on humanhealth and the environment that result when ahazardous material leaves an industrial systemand undergoes subsequent transformations.(Relative to lead, such transformations areeven more complex in the case of several othertoxic metals, such as mercury, cadmium, andchromium.) Defining system boundaries thatexclude these transformations from consider-ation will impoverish any analysis.

The LRHM analysis treats lead in gasolineadditives and lead in batteries on the same foot-ing. It thereby implies that societal goals for themanagement of the two uses should be thesame—in particular, that because it is wise tostop using lead additives, it must also be wise tostop using lead batteries. Little can be done toprevent the lead in gasoline, after combustion,from finding its way to people in the dangerousform of fine particles. But much can be done toaffect the fate of lead in batteries. From a soci-etal perspective, the appropriate goal for thelead battery industry should be clean recycling,where almost all used batteries are retrievedand where, during recycling, lead releases to theenvironment have almost no environmentaland public health impacts.

The small and shrinking share of primary leadin today’s lead batteries has two complementaryimplications for clean recycling. First, unless pri-mary production is much dirtier than secondaryproduction, secondary production should be theprincipal focus of clean recycling. Second, a

clean recycling system can be achieved only ifboth primary and secondary smelters meet strin-gent environmental standards.

Achieving a battery management system thatapproaches the industrial ecology ideal of cleanrecycling will require much work worldwide. Theenvironmental performance of many of theworld’s primary and secondary lead smelters is farbelow the environmental performance of theworld’s best smelters. In the poorly performing fa-cilities, worker lead exposure is very high, andpeople in the nearby communities have elevatedblood levels. Some of the worst environmentalperformance is found in smelters in the develop-ing world (Greenpeace 1994; Woolf 1994). Nonation can be said to have a clean recycling sys-tem unless all of its batteries at end of life go tosecondary smelters and battery manufacturingplants that meet demanding environmental andoccupational health standards.

It will not be enough for all facilities to reachthe standards of today’s best managed facilities, be-cause even in these facilities, workers have bloodlead levels exceeding the levels of well-docu-mented adverse health effects. Better documenta-tion of the recycling system is needed, includingbetter measurements of air emissions, communityexposures, worker exposures, and lead transfersacross countries. And data need to be acquired orindependently confirmed by government agen-cies, environmentalists, and others who can be ex-pected to have an independent view.

The lead industry as a whole should be chal-lenged to approach the industrial ecology ideal.Some intrinsically dissipative uses of lead, in-cluding leaded gasoline, are already beingphased out in favor of more benign substitutes.The lead battery, by far the most important lead-containing consumer product that does not dis-sipate lead with use, can become one of the firstexamples of a hazardous product managed in anenvironmentally acceptable fashion. The toolsof industrial ecology are well matched to thecharting of progress.

Acknowledgments

We wish to thank Mark Baumgartner, L. Pa-sha Dritt, James J. Fanelli, and MargaretSteinbugler for research assistance. We have



benefited from many reviews of an earlier draft ofthis manuscript and related discussions. Particu-larly helpful in increasing our understanding ofadvanced automobile technologies and associ-ated policies were Andrew Burke, John DeCicco,Frederick Dryer, Patrick Grimes, Joseph Keating,Thomas Kreutz, Jameson McJunkin, Paul Miller,Joan Ogden, Marc Ross, William Schank, DanielSperling, and Robert Williams. We have beeninformed about battery management and associ-ated emissions by David Allen, Marijke Bekken,Douglas Bice, Katie Chiampou, Leland Deck,Robert Fletcher, Linda Gaines, Lester Lave,Neal Lebo, Leonard Levin, William McKusky,Carol McLaughlin, Francis McMichael, SaskiaMooney, Joseph Norbeck, Chris Whipple, andLinda Wing. We have been alerted to publichealth issues by Robert Elias, Philip Landrigan,Joel Schwartz, and Ellen Silbergeld. We have en-joyed many exchanges about the emerging prin-ciples of industrial ecology with Brad Allenby,Jesse Ausubel, Robert Frosch, Thomas Graedel,John Harte, Reid Lifset, David Rejeski, ThomasSpiro, Iddo Wernick, and Stefan Wirsenius.Comments by John DeCicco, Harold Feiveson,Francis McMichael, Ellen Silbergeld, and Rob-ert Williams have enabled us to sharpen our ar-gument. We are grateful for the assistance ofKathy Shargo and Laura Schneider in preparingthe figures and Elaine Kozinsky in preparing themanuscript.

Notes

1. Clean recycling has a dynamic dimension as well,given that product demand varies over time. Forseveral decades the lead recycling system has man-aged the starting-lighting-ignition (SLI) batterythat provides starting power for gasoline-poweredvehicles. The system has grown to a global scale ofmore than a hundred million recycled batteries peryear. A clean recycling system must assure that themining and primary processing of the lead requiredto provide for an increasing stock of lead productsis conducted in environmentally responsible ways.It must also assure environmentally responsiblecontraction. Although no successor to the SLI bat-tery is in view, some day a competitive alternativemight challenge its domination. Battery lead incars on the road would no longer have a predict-

able destination in a next generation of batteries,and change would have to occur carefully to avoidlarge accumulations of lead stocks and large re-leases of lead to the environment. The scaling backof successful recycling systems is a general issuethat industrial ecology can illuminate.

2. In response to the first article (Lave, Hendrickson,and McMichael 1995), Science published (11 Au-gust 1995 issue) eight of what it said were “an un-usual number of letters,” as well as a reply by theauthors. The second article (Lave et al. 1996) su-persedes the first; it avoids many of the numeri-cally controversial and distracting assumptionsthat were the focus of a number of these letters.The second article also addresses the air qualitybenefits claimed for the electric vehicle (reducedozone concentrations) and finds them to be mini-mal in Los Angeles and New York City; we do notaddress this portion of the second article.

3. The estimate of 1% is the geometric mean of therange (0.5% to 2%) cited in the LRHM analysis.Using the upper value of the range (2%) leads tothe conclusion that lead emissions from the elec-tric car are six times greater than lead emissionsfrom the gasoline-powered car.

4. The estimate of 0.03% is the geometric mean ofthe range (0.02% to 0.05%) cited in the LRHManalysis.

5. In the LRHM analysis the car with an SLI batteryis assumed to be driven 19,300 km per year, likethe battery-powered electric car. Then about 100mg of lead would be processed for the SLI batteryper kilometer of driving, which is three to fourtimes as much lead as would be processed for leadadditives for the fuel-efficient car running onleaded gasoline.

6. When a battery-powered electric vehicle substi-tutes for a gasoline-powered vehicle, local airpollution will be reduced, provided that the gen-eration of the electricity to recharge the batterydoes not produce compensating air pollution inthe same airshed. There will be no compensatingincreases in local air pollution if the electricitycomes from hydropower, nuclear power, geother-mal energy, wind, photovoltaics, or solar thermalpower. Even if the electricity is produced nearbyfrom fossil fuels, there will be little compensatinglocal air pollution from two of the significant airpollutants, volatile organic compounds and car-bon monoxide, because it is much easier to re-duce these emissions at a central station powerplant than on-board a vehicle (Hwang et al.1994). But, if the electricity is produced nearbyfrom fossil fuels, there will be substantial compen-



sating local air pollution from nitrogen oxides(which are particularly important in smog forma-tion), even if pollution controls are in place, be-cause central station power plants are notdecisively better than vehicles in controlling ni-trogen oxide emissions. There will also be localpollution from sulfur oxides and particulates, es-pecially if the energy source for the electricity iscoal. Of course, when the production of the elec-tricity that recharges a battery occurs at a powerplant that is a considerable distance from wherethe battery is substituting for a gasoline engine onthe road, most of the local environmental im-pacts associated with the production of the elec-tricity will be displaced to the vicinity of thepower plant; they do not disappear.

7. The original (1990) ZEV mandate also requiredthat 2% of sales be ZEVs by 1998 and 5% by2001. In 1996, these two deadlines were re-scinded as a result of negotiations between thestate of California and the automobile industry,but the 10% sales requirement for 2003 was reaf-firmed.

8. Energy density is the key variable determiningthe range. Burning a kilogram of gasoline releasesabout 60 times more energy than is released whena kilogram of reactants in the lead-acid battery(lead, lead dioxide, and sulfuric acid) combine toproduce lead sulfate and water. This factor of 60captures the difficulty of achieving adequaterange for a car running on lead batteries. A cardoes not go very far on one-sixtieth of a tank ofgas! The battery electric car compensates forsome of this energy density handicap by convert-ing chemical energy two to three times as effi-ciently to energy at the wheels, and it furthercompensates by carrying several times more massas battery than today’s gasoline-powered car car-ries as gasoline when the tank is full. Still, thelead-battery electric car has to settle for aboutfive times less range.

9. A variant on the fuel-cell/battery all-electric hy-brid vehicle might use an advanced battery forbase-load power.

10. Substituting electricity for onboard gasoline (orfor some other petroleum-derived fuel) can some-times have a negative impact on global warming.For example, carbon savings implicit in energy-efficient electric vehicles may not be realizedwhen electricity is produced in carbon-intensivecoal-fired power plants. This is the reason why acombustion-engine/battery hybrid can outscore avehicle that derives its power from electricitygenerated at a separate power plant, when judged

against the joint objectives of local air quality, oilsecurity, and global warming. If oil security isgiven great weight in the comparison, however,the vehicle that derives its power from electricitygenerated at a separate power plant is likely tocome out ahead, because little oil is used to gen-erate electricity today.

11. Three times as much energy is released per kilo-gram of fuel in a hydrogen fuel cell than whengasoline is burned. Still, achieving long range willdepend on finding ways to carry the hydrogen onboard, either chemically or physically, in low-massand low-volume ways. Carrying the hydrogen un-der pressure as a gas requires a tank made of high-strength, light-weight materials. Carrying thehydrogen as part of a loosely bonded compound,such as a metal hydride, adds significant mass forthe rest of the compound. Carrying the hydrogenembedded in an organic molecule like methanolrequires a compact “reformer” on board for chemi-cal processing. There is flexibility in reformer de-sign for a hybrid vehicle, because the peakingdevice provides a fast response time.

12. The international unit is micromoles per liter. Onemicrogram per deciliter is 20.7 micromoles per li-ter. The factor of 20.7 is one-tenth the atomicweight of lead.

13. These values are averages over readings at 139 ur-ban sites where 24-hour measurements are per-formed every six days. The value reported foraveraging across sites is the highest of the fourquarter-year averages of these 24-hour readings.

14. The denominator is obtained by adding 840,000metric tons of “available” lead from batteries fortransportation, plus 125,000 metric tons of avail-able lead from industrial batteries for motive andstationary power, and subtracting 116,000 metrictons of net exports of lead associated with thesebatteries. The four largest contributions to thetotal available lead from batteries for transporta-tion are: (1) the 591,000 tons of lead in the 66.1million batteries in 1990 passengers cars andlight commercial vehicles (derived by assumingthat 8.94 kg is the average mass of lead in thesebatteries); (2) the 103,000 tons of lead in the 6.3million batteries in 1991 trucks and heavy-dutycommercial vehicles (16.3 kg average mass oflead); (3) the 47,000 metric tons of lead in the3.6 million 1991 marine batteries (13.0 kg aver-age mass); and (4) the 36,000 metric tons of leadin the 1.9 million 1991 golf carts (18.4 kg aver-age mass of lead). The net exports of lead associ-ated with these batteries is the differencebetween 127,000 metric tons of exports and



11,000 metric tons of imports (Battery CouncilInternational 1995).

15. This experiment had the unfortunate complica-tion that levels below 5 µg/dL were reported as be-low the detection limit and were notdistinguished from one another. In computing theaverage exposures, all readings below 5 µg/dL wereset equal to 2.5 µg/dL.

16. Air emissions were sampled from six stacks andtwo vents (the vents were considered to accountfor the fugitive emissions), and the total air emis-sions rate was found to be 210 grams per hour. As-suming that this rate was characteristic of theaverage emission rate for the plant during its8,500 hours of operation in 1990, the air emis-sions from the Vernon plant would have totaled1.8 metric tons that year. By CARB’s estimate,93,000 metric tons of lead were processed thatyear, and thus the air emissions factor (1.8/93,000) is 0.002% (McLaughlin 1996).

17. The smelter data were reported by five companiesowning smelters, with 2,111 tested employees;the full distribution of blood lead levels reportedis 44.3% below 20 µg/dL, 33.2% between 20 µg/dL and 30 µg/dL; 16.7% between 30 µg/dL and 40µg/dL; 5.3% between 40 µg/dL and 50 µg/dL; and0.5% above 50 µg/dL. The battery-plant datawere reported by 20 companies owning batteryplants, with 17,343 tested employees; the com-plete distribution of levels reported is 56.3% be-low 20 µg/dL, 28.7% between 20 µg/dL and 30 µg/dL; 12.5% between 30 µg/dL and 40 µg/dL; 2.3%between 40 µg/dL and 50 µg/dL; and 0.2% above50 µg/dL (Battery Council International 1996).

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