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“The World Trade Center is a living symbol of man’s dedication to world peace. . . .

[T]he World Trade Center should . . . become a representation of man’s belief in humanity,

his need for individual dignity, his beliefs in the cooperation of men,

and through cooperation, his ability to find greatness.”

Minoru Yamasaki, chief architect of the World Trade Centerquoted in Architects on Architecture: New Directions in America, 1978

On 11 September 2001, over a milliontons of steel, dust, and debris fell to

earth on the island of Manhattan. Whereonce the two giant towers of the World TradeCenter had stood, now ruins lay in clouds ofsmoke. The buildings, sym-bols of America’s interna-tional economic influence,had been destroyed by ter-rorist attacks, and over4,000 lives had been lost.When two hijacked air-planes fully loaded with91,000 liters of jet fuel flewinto the twin towers of theWorld Trade Center, theresulting explosions andfires burning at over1,800°F caused the build-ings to collapse into them-selves. The enormous heat,combined with the burningof a vast number of materi-als such as asbestos, concrete, computers, car-peting, and furniture, created a gaseous cloudof potentially toxic dust and smoke that tookweeks to dissipate.

Following the initial shock of the largestdeath toll ever from terrorism on U.S. soil,federal, state, and local officials along withscientists across the nation began the enor-mous process of recovering human remains,removing and disposing of debris, and evalu-ating the potential continued health threat toemergency responders and the surroundingcommunity from environmental exposuresrelated to the attacks.

A Storied History

The idea for a central site dedicated toworld trade had been considered for NewYork City since the end of World War II,but the right conditions of finance, politicalwill, and appropriate location didn’t cometogether until the early 1960s. The PortAuthority of New York and New Jersey, thecity agency in charge of transportation mat-ters, was responsible for commissioning themonumental venture.

The goal was to build 10 million squarefeet of new commercial office space on a 16-acre site, while also accommodating futureand existing subterranean railways. Inev-itably, this meant building upward to

unprecedented heights. Theproject would put to the testconstruction and designtechnologies that were newat the time and that repre-sented real challenges tobuilders, architects, and con-struction engineers.

With this challenge inmind, chief architect MinoruYamasaki studied over 100different building configura-tions before choosing theconcept of two twin towersrising from an open plazaflanked by three other low-rise structures. Faced withthe complexities of building

to new heights, Yamasaki and engineers JohnSkilling and Les Robertson worked to seam-lessly merge design and structure.

They employed an innovative structur-al model consisting of a hollow tube madeof steel columns set only 22 inches apart.This exoskeleton of steel lattices acted aswind bracing to resist outside forces andmade it unnecessary to have indoor col-umns in the office spaces. In the upperfloors there was as much as 40,000 squarefeet of open office space per floor. The steellattice was connected to floor supports radi-ating from a steel central core containingelevators and stairs.

The enormous weight of the structurewas anchored to the bedrock located 75 feetbelow ground that makes possible down-town Manhattan’s high-rise skyline. Giventhe proximity of the site to the HudsonRiver, the whole complex had to be con-tained in a “bathtub,” an impermeable wallmore than 3,000 feet long encircling theexcavation site. The below-ground founda-tion was used to house seven levels of stores,subway lines, commuter rails, and garages.

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Excavation to build the foundation removedover a million cubic yards of earth and rock.Instead of being trucked away for disposal,excavated soil was used to create 23 acres offill in the Hudson River adjacent to theWorld Trade Center site. The new groundsclaimed from the river were developed into ahousing complex known as Battery ParkCity, where more than 9,000 people live in25 buildings.

After seven years of construction, theWorld Trade Center ribbon-cutting ceremo-ny was held on 4 April 1973. The TwinTowers were a blend of structure and func-tion that provided a centralized space fromwhich world business was conducted. Itsproximity to Wall Street and to the New YorkStock Exchange was also part of the attrac-tion for many of the tenants who later filledthe work spaces. The World Trade Centerhoused 9 million square feet of rentableoffice space in two 110-story towers, eachnearly 1,400 feet tall. The towers providedworking space for 292 companies with over50,000 employees. With a panoramic view45 miles in every direction, the towers alsoprovided a major tourist attraction in New

York City. Over 90,000 people visited thetowers on any given day.

Ground Zero

The six story–high pile of compacted rub-ble that resulted from the fires and collapseof the towers became known as GroundZero or simply “The Pile.” In the first daysafter September 11, immediate physicaldangers were everywhere. Buildings adja-cent to the towers collapsed or sufferedmajor damage. Intense fires continued toburn, and a massive cloud of dust andsmoke spread with the prevailing winds formiles out from the site.

All this occurred in the middle of anintensely populated urban center. New YorkCity’s financial district encompasses notonly a vibrant working community but alsoa significant residential neighborhood.Nearly 20,000 people live within a half-mile of Ground Zero, close to 3,000 ofthem children.

Following the disaster, people whoworked in the financial district fled and werebarred from returning to work immediately,and more than 20,000 neighborhood

residents were displaced. “No one couldhave conceived of a disaster like this,” saysMary-Helen Cervantes-Gross, chief of pub-lic outreach for the U.S. EnvironmentalProtection Agency (EPA) Region 2 Office inNew York City, whose office was only a fewblocks from the disaster.

In response to the attacks, thousands offirefighters, police officers, medical person-nel, and other types of rescue and relief work-ers poured in to the Ground Zero site to helpwith the rescue and recovery efforts. In thedays soon after September 11, many workedaround the clock in thick smoke and dust—sometimes with respirators and other person-al protective equipment, sometimes not.Many continue to work amid the rubble andunknown environmental exposures.

Among the immediate exposure con-cerns are agents such as asbestos from con-crete, polychlorinated biphenyls (PCBs)from electrical wiring, dioxins from jet fuelcombustion, particulate matter from pulver-ized concrete and other building materials,and lead and other metals from computersand monitors [see table below]. Noise pollu-tion from the heavy machinery used in the

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Contaminants Potentially Present* at the World Trade Center Site

Contaminant Health Effects Source

Asbestos Carcinogenic. Causes tissue scarring in the lungs when inhaled over Used as an insulator and fire retardant, long periods and can lead to asbestosis, mesothelioma, and lung cancer. applied to steel beams.

Benzene Flammable and carcinogenic. Short-term effects include dizziness, Combustion of plastics.headaches, and tremors. Long-term exposure can lead to leukemia.

Biohazards Exposure to blood and body parts can transmit infectious diseases Human remains of the victims trapped such as hepatitis and AIDS. After long periods, they may pose little in the rubble (less than 15% of the hazard to health, although finding human remains can cause bodies have been recovered).psychological trauma.

Chromium Carcinogenic when inhaled at high concentrations. Dermal contact Video and computer monitors. can cause skin ulcers.

Copper In large amounts can cause dizziness, headaches, vomiting, and Electrical wiring and cables.damage to the kidneys and liver.

Diesel fumes Asthma trigger. Can aggravate symptoms in asthmatics. Truck traffic and heavy machinery fromthe cleanup effort.

Dioxins Chloracne is a short-term effect of exposure. Strong evidence for Combustion of polyvinyl chloride foundcarcinogenic, teratogenic, reproductive, and immunosuppressive in electrical cables and other insulatingeffects. Persist and bioaccumulate in the environment and food chain. materials and some plastics.

Freon Damages the ozone layer. When burned, can produce phosgene, a Refrigeration and air-conditioning potent cause of severe and life-threatening pulmonary edema. equipment.

Lead Neurotoxic. Damages the central nervous system, especially in Video and computer monitors, rustchildren. Can also cause kidney and reproductive damage in adults. proofing paint used on steel beams.

Mercury Neurotoxic. Damages the peripheral nervous system, especially in Thermometers and other precision children. instruments.

Particulate Asthma trigger. Can aggravate symptoms in asthmatics. Can also Pulverized concrete and other materialsmatter aggravate cardiovascular disease. Smaller particles (PM2.5) may be (large particles); smoke, dust, and soot

more potent than larger particles (PM10). from combustion (small particles).Polychlorinated Carcinogenic. May also cause hormonal problems and reproductive Transformers and other electrical biphenyls and developmental abnormalities. Persist in the human body and equipment.

the environment. Sulfur dioxide Pulmonary toxicant. Can cause severe airway obstructions when Combustion of many materials.

inhaled at high concentrations. Can burn the nose and throat.

* Not all of the pollutants listed are currently being tested for at the World Trade Center site, and final data are not yet available for pollutants that are being tested for.

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rescue and cleanup efforts isalso a concern. The EPA imme-diately began monitoring theair around the site for somepollutants, but the long-termeffects of the potential expo-sures is yet to be known.

A Community Comes to Grips

Catherine McVay Hughes’shome is one block fromGround Zero. Hughes is themother of two small childrenand the president of an onlineresource center helping fami-lies manage asthma calledAsthmaMoms.com. Lookingout the window at the smokestill rising from the rubble onemonth after the attacks, shesays, “Our home is now nextdoor to an uncontrolled incin-erator burning who-knows-what twenty-four hours a day.”

Hughes and 8,000 otherneighborhood residents remaindisplaced from their homes. Inan attempt to remove air haz-ards from her family’s home,Hughes has bought four airpurifiers, which she keeps run-ning constantly in her apart-ment, and she has arranged tohave all upholstered furnitureand beds removed. The Hughesfamily will remain living in aBrooklyn hotel at least throughthe end of the year. As she says,“We don’t know what is comingout of that smoke and what theeffects may be on our children.”

She is not alone in thisconcern. According to JoelForman, an assistant professorof pediatrics at the Mount SinaiSchool of Medicine in New York, specialattention must be placed on the possibleeffects on small children of any pollutantsbeing released from the site. “Since small chil-dren breathe air that is closer to the ground, itis possible that they may breathe in higherdoses of the dust as it settles,” he says. Becausechildren’s organs and systems are still devel-oping, they may also be more vulnerable tochemical insult. These are things that need tobe considered before children are returned tothat environment, he says.

There are 36 schools located within thefour ZIP codes closest to Ground Zero, serv-ing over 19,000 students from kindergartenthrough high school. Dust and debrisentered the schools following the attacksthrough windows and ventilation systems.

In order to protect children, theseschools are being tested for environmentaltoxicants and cleaned especially carefully bygovernment agencies in charge of respond-ing to the emergency. Strict regulations forcontaminants in schools are being applied.For example, the Asbestos Hazard Emer-gency Response Act (AHERA) of 1986requires that a standard for asbestos 10times stricter than the Occupational Safetyand Health Administration (OSHA) stan-dard for workplaces be applied in schools.This is necessary because “no one knowswhat the risk may be for small childrensince they have a longer time to develop anycancer that may be caused by asbestos expo-sure,” says Philip Landrigan, chairman ofthe Department of Community and

Preventive Medicine at the Mount SinaiSchool of Medicine.

Along with applying existing measures,there are new government initiatives that willaid in limiting the impact of the disaster onchildren’s environmental health. In a speechat the EPA Region 2 Asthma Summit held atthe Mount Sinai School of Medicine onOctober 12, EPA administrator ChristieWhitman stated, “In many ways, there’s nobetter time to describe what is happeningwith our new efforts on asthma in the city.”

Asthma is a special concern in thiscommunity. Asthmatics, especially children,are more susceptible to many air pollutantsthat can trigger symptoms of the disease.Some types of air pollutants such as fineparticulates that were liberated into the

A changed landscape. Following the attacks, an enormous cloudof dust and smoke blanketed the neighborhood surrounding theWorld Trade Center, obliterating normal life and raising concernsthat health consequences, as well as the emotional aftershocks,may endure for a long time to come.

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environment during the collapse of theWorld Trade Center buildings are known tobe potent asthma triggers. However, the asth-ma-related effects of other pollutants thatmay have been released is largely unknown.

At an October 11 community forum todiscuss health impacts of the World TradeCenter attacks, the auditorium at PaceUniversity, located about four blocks fromthe World Trade Center site, was filled tocapacity with residents asking questionsabout what toxicants may be in the air, whenit will be safe to return home, and what thelong-term health effects may be from expo-sure to the dust and smoke. These areimportant and practical questions, but theyare difficult to answer because of theunprecedented nature of thedisaster. Scientists and publichealth officials are working toidentify and quantify the toxi-cants that may have beenreleased, and to determine thehazards that these agents maypose to the surrounding com-munity, as well as to emergencyworkers at the site.

Hazards to Heroes

During the first few days afterSeptember 11, the main goal ofoperations at Ground Zero wasto find and rescue survivorsthat may have been trapped inthe rubble. Thousands of vol-unteers from as far north asMontreal and as far south asTexas converged in New YorkCity to offer their help. Themost serious immediate hazardsto these workers were related totraffic safety, falls, cuts, andcrush injuries.

As the site was stabilized,other occupational hazards

became more apparent. PortAuthority officials, who were con-cerned about the safety of rescueworkers digging through the rubblewithout appropriate personal pro-tective gear such as respirators,requested recommendations fromacademic researchers in occupa-tional health and safety programsfrom around the area.

Mark Robson, an associate pro-fessor and director of the Environ-mental and Occupational HealthDivision at the University ofMedicine and Dentistry of NewJersey (UMDNJ) School of PublicHealth, headed the team. He says,“During the search and rescuephase, good industrial hygiene was

put on hold”—the priority at that time wasto find survivors quickly. However, saysMichael Gochfeld, a professor of environ-mental and occupational health at the RobertWood Johnson Medical School and a mem-ber of OSHA’s occupational safety advisoryteam, “As the operation moves from rescue torecovery, an appropriate respirator programwill need to be put into place.”

Such a program is being implementedby OSHA. Nancy Clark, an industrialhygienist at the Irving J. Selikoff ClinicalCenter for Occupational and Environ-mental Health at the Mount Sinai School ofMedicine, is collaborating with OSHA inestablishing this program. “The programmust medically screen, fit test, and train

workers in the proper use of respirators forthe program to be effective,” she says. Butthese steps couldn’t be taken during theimmediate emergency, so many workers mayhave been affected by toxicants in smoke anddust. According to Stephen Levin, co-direc-tor of the Selikoff Center, several workershave been stricken with new-onset asthma,and at least one worker had to be treated forcarbon monoxide poisoning. To assess thepossible long-term effects of exposures,Selikoff Clinic staff plan to conduct clinicalassessments on workers who will be contact-ed through their labor unions over time.

Federal regulatory and research agencieswill continue to evaluate the levels of con-tamination, the potential short-term healtheffects to workers, and long-term healthimpacts on both workers and the surround-ing community through a number of studies.Several of these will be conducted undergrants from the NIEHS to its EnvironmentalHealth Sciences Centers and one Children’sEnvironmental Health and Disease Preven-tion Research Center in the Manhattan area.The NIEHS has also awarded grants to fiveorganizations to provide much-neededequipment, resources, sampling, and trainingto the workers engaged in the World TradeCenter cleanup [see “NIEHS Responds toWorld Trade Center Attacks,” p. A526].

Asbestos. The release of asbestos fibersfrom the World Trade Center site into theneighboring community has become one ofthe major environmental concerns. Asbestosis a known human carcinogen. It can cause

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Dangerous days. Ironworkers balance precariously as they cut through the rubble of the World Trade Center.

A helping hand. FEMA community relations worker JeanFequiere helps Manhattan resident Carmen Rivera throughthe federal assistance registration process following theWorld Trade Center attacks.

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lung cancer and mesothelioma, a lung condi-tion specific to asbestos. Workers who areexposed to high doses over long periods oftime are particularly at risk.

There is currently no clinical examina-tion that can detect whether a person hasbeen exposed to asbestos. The damage to thelungs caused by asbestos only appears aftermany years, and can then be seen on a chestX ray. According to David Prezant, chief pul-monary physician of the New York City FireDepartment, chest X rays have been takenfor 350 of about 4,000 firefighters whoworked at the site. Some researchers havecriticized this effort, maintaining that anydamage wouldn’t show up at this early stage.However, the data can serve as a baseline forworkers who may be followed over time.

Ironically, concerns about asbestos arenot new to the World Trade Center. Duringthe construction of the towers, asbestos-laden slurry was sprayed on steel beams as afire retardant. The late professor Irving J.Selikoff of the Mount Sinai School ofMedicine, considered by many to be thefather of modern occupational medicine,observed that during construction “snowfallsof asbestos-containing material” fell from theconstruction site over widespread areas ofdowntown Manhattan. Based on data gath-ered by Selikoff and colleague WilliamNicholson, the New York City Departmentof Air Resources issued a ban on the sprayingof asbestos fibers in New York on 13 May1970 (a year before the federal governmentmade a similar nationwide ruling).

By that time, 5,000 tons of asbestos-containing fireproofing material had beensprayed up to the fortieth floor of one of thetowers. Mineral wool and fiberglass wereused as replacements for the asbestos fromthen onward in the construction process, butsome asbestos may also have been applied byhand in the central core of the buildings afterthe ban was issued.

The collapse of the Twin Towers causedthe asbestos fibers that had been safelytucked into the walls of the buildings to dis-perse in the resulting dust cloud. “Asbestoscontamination was one of the very first envi-ronmental health concerns that we had,” saysCervantes-Gross. Since September 11, theEPA has taken samples of the local air, dust,water, river sediments, and drinking waterand analyzed them for the presence of pollu-tants, including asbestos, that might pose ahealth risk to response workers and the pub-lic. All 99 samples taken in and aroundGround Zero between October 12 andOctober 15 showed asbestos levels of lessthan 70 structures [particles of asbestos] persquare millimeter, which is the AHERA stan-dard for allowing children to reenter schoolbuildings after asbestos removal activities.

However, at least 27 earlier readings hadshown levels that were above this standard.

Since the attacks, controversy has swirledaround the EPA response to the threat ofenvironmental contaminants in the dust.Results obtained by independent contractorswho tested the asbestos content in dust sam-ples suggest that the force of the explosionsmay have pulverized the asbestos fibers intoshort particles that are too small to be seen byconventional testing methods used by theEPA and other agencies.

One such contractor, HP Environmentalof Herndon, Virginia, submitted its results to

the American Industrial Hygiene Associationfor review (that report is not yet available).“It is hard to comment on this without see-ing [the report],” says Landrigan. However,he states that although it is known thatsmaller particles can enter deeper into thelungs, long fibers, which ordinarily don’tpenetrate as easily into lungs, can cause morecellular damage, and thus are consideredmore toxic. Landrigan also notes that a mix-ture of fibers of many lengths was released atthe site.

Although air levels of asbestos may bebelow the range that would require regulatory

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A mountain of loss. Two days after the attacks, urban search and rescue teams continued thesearch for survivors below the towering wreckage of the World Trade Center.

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action, dust that has accumulated on win-dowsills and sidewalks and inside homesthroughout the area should be treated as if itcontains asbestos, suggests Levin. He believesthat due to unequal release of the asbestos,only some samples may contain the sub-stance, but that all dust exposures should beconsidered potentially hazardous.

The New York City Department ofHealth has issued guidelines for residentsreturning to and attempting to clean theirhomes. To reduce dust recirculation, thedepartment recommends using high-efficiency particulate air filtration vacuumswhen cleaning up apartments, if possible.Wetting down the dust before removing it isalso recommended in order to reduce thedispersion of the asbestos particles.

Unfortunately, recommendations forproper cleanup did not reach all residentsbefore they returned to their homes. “Thecity was under pressure to let people intotheir homes as soon as possible,” saysGochfeld, so many residents may not havefollowed these procedures. Even so, “thechances of getting mesothelioma or otherasbestos-related disease is vanishingly smallfor residents,” says Levin, as exposures wouldhave to occur for much longer periods tohave a detectable effect.

Other researchers believe, however, thateven single exposures can be hazardous, withlong-term effects. And it is possible that cer-tain susceptible populations such as smokersmay be at higher risk. According to

Landrigan, smokers run about 55 times thenormal risk of developing lung cancer afterexposure to asbestos.

For this reason, many community resi-dents are contracting with professional clean-ing services to assist them. The FederalEmergency Management Agency (FEMA)has provided some relief to assist familieswith this expense. Over 3,400 requests forassistance have been filed with the agency todate. (Area businesses and stores are alsoreceiving help from FEMA and the city incleaning up the dust.)

However, the widespread use of cleanupcompanies that are not well certified—forinstance, by the New York Committee forOccupational Safety and Health—can createother problems. At a community forum heldon October 18 at New York University, resi-dents raised concerns about the risk involvedin the dust cleanup. Trina Semorile, a com-munity resident, said, “I am afraid that weare transferring our risk to the poor workerswho come to clean our homes.” This concernarises because many cleanup crews have beenput together that do not have the propertraining and equipment to handle thesekinds of materials. As Joel Shufro, executivedirector of the New York Committee forOccupational Safety and Health, says,“Cleanup workers are at higher risk. Someare being given respirators but no training.”

Particulate matter. The force of theexplosions and collapse of the World TradeCenter buildings shattered the cement

structures, sending plumes of dust andsmoke far into the air. The resulting parti-cles are of various sizes and composition.They can aggravate illnesses such as asthma,bronchitis, and some cardiovascular condi-tions in people who breathe the air aroundGround Zero.

The EPA regulates particulate matteraccording to size. The larger particles, thosemeasuring 10 microns or less (PM10), arealso called inhalable particulates because theycan penetrate the human respiratory systembeyond the larynx into the airways. Smallerparticles of 2.5 microns or less (PM2.5) areconsidered in the respirable range becausethey can penetrate even deeper into thelungs, to the unciliated regions. This differ-ence in lung penetration explains why sever-al studies have found that the PM2.5 fractionof PM10 may be more toxic.

The level of concern to protect sensitivepopulations, including children, the elderly,and people with heart or lung disease, is 40micrograms per cubic meter measured over a24-hour period for fine particulates. Abovethis level, the EPA recommends that sensitivegroups reduce their exposure. Air monitoringbeing conducted by the EPA at sites near theWorld Trade Center wreckage shows thatdaily average measurements for PM2.5 fallbelow the standard.

However, when hourly measurements areconsidered, occasional peaks of fine particu-lates have been recorded that surpass the levelof concern. This occurs often at night, when

winds are calm and thermalinversions occur that reducethe dispersion of particles,explains George Thurston, anassociate professor of envi-ronmental sciences at NewYork University. “Some peaks,especially at night, may havehealth implications for sensi-tive populations,” he says,including onset of asthmaattacks in asthmatics. To alle-viate this problem, Thurstonproposes to reduce theamount of recovery workbeing done during those crit-ical hours when the air pollu-tion burden appears toincrease.

Lead. Although manyuses of lead were banned inthe United States in the1970s, lead continues to be athreat to public health.There are several sources oflead that may have beenreleased during the destruc-tion of the World TradeCenter. Computers contain

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Standing on the brink. Despite losing many of their own, firefighters continue to brave unknown threats.

small quantities of lead in the solder usedfor circuit boards. Computer monitors maycontain as much as four pounds of leadeach, according to the Silicon Valley ToxicsCoalition. Because there were possibly tensof thousands of computers in the offices ofthe World Trade Center, the amount of leadfrom this source may be significant.

In addition, it was common practice atthe time of the construction of the buildingsto use lead-based paint to rustproof steelbeams. Investigations being conducted byPaul Lioy, associate director of the Environ-mental and Occupational Health SciencesInstitute at Rutgers and UMDNJ, show thatlead particles from paint chips and paintdust can be found in the dust originatingfrom the site. He has obtained measure-ments of lead in dust ranging from 38 to635 micrograms per gram. “These levels arenot high, but are moderately high and can-not be ignored,” says Lioy.

Lead can persist in the body for verylong periods and can accumulate in bone,from which it can be mobilized and trans-ferred to fetuses during pregnancy andinfants during breast-feeding. Although theEPA action level for lead poisoning is 10micrograms per deciliter in blood, it hasbeen argued in the scientific literature thatmuch lower levels can cause detrimentalneurologic effects in children.

Some investigators who have beeninvolved in the work related to the WorldTrade Center disaster suggest that dust sam-ples in homes and parks should be carefullymonitored for lead content. This is importantas cleanup proceeds and residents start return-ing to their homes. Many residents may notbe able to properly decontaminate theirhomes of lead. For example, says Lioy, “Youwould not be able to see one gram of lead dustspread over a one-square-foot surface.”

PCBs. PCBs were present in differenttypes of electrical equipment present at theTwin Towers at the time of the attacks. Theyhave been used as lubricants and coolants incapacitors, transformers, and other equip-ment because they are good insulators. Themanufacture of PCBs was halted in theUnited States in 1977, but equipment in thebuildings made before that year may havecontained PCBs.

Exposure to this class of compounds hasbeen associated with toxicity to the develop-ing brain in humans and animals. PCBs mayalso affect the hormonal system in fetuses.Another major concern about PCBs is thatthey are lipophilic, and thus tend to accu-mulate in the food chain and persist in theenvironment and the body.

So far, all samples of air analyzed by theEPA for PCBs at locations surroundingGround Zero have been below the EPA’s

screening level. PCBs were not detected inthe vast majority of samples. However, theywere detected in some instances within thearea where the recovery efforts are takingplace. It appears that the release of certaincontaminants such as PCBs may be episod-ic, occurring when work at the site disruptspockets of toxic materials buried in therubble. As Landrigan puts it, “Exposure isintermittent, but the threat of exposure isconstant.”

A Mountain of Waste

The destruction of the Twin Towers gener-ated over 1.2 million tons of tangled wasteof innumerable materials, according to astudy commissioned by the city that usedcomputer modeling to estimate the amountof debris. Most of the debris is made up ofconstruction materials such as huge steelbeams and mountains of concrete, dottedwith the remains of the businesses that oper-ated there and the equipment they reliedon. All of this waste is potentially laced withtraces of some or all of the contaminantsdiscussed in this article, as well as theremains of the victims of the disaster. Only

549 bodies have been recovered from thesite so far.

To date, close to 500,000 tons of debrishave been removed from Ground Zero. It isestimated that it will take about a year forcleanup to be completed, partly because ofthe complexity of the recovery effort at thesite, which is at once a crime scene, a ceme-tery, a hazardous waste site, and a source ofvaluable recyclable materials.

The city is making efforts to identifyrecyclable materials that can be sorted onsite for recovery. For example, the PortAuthority has estimated that each of thetowers contained 78,000 tons of recyclablesteel, which can be sold for up to $100 perton. Other materials such as aluminum andcopper can fetch much more in the scrapmetal business. It has not yet been decidedhow any monies collected in this way willbe distributed.

Most of the rest of the debris is beingtaken by truck or barge to the Fresh KillsLandfill on Staten Island. The landfill col-lected New York City garbage for fivedecades and had been closed to additionaldisposal six months before September 11. It

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The work of recov-ery. The rumble ofmachinery continues24 hours a day asvast amounts of deb-ris are removed from“The Pile” at GroundZero and trucked andferried to “The Hill”at the Fresh KillsLandfill. Investigatorsthere comb throughit carefully for evi-dence of the crimeand personal effectsof the victims.

was immediately reopened to accept thedebris from the World Trade Center.

At the top of the 180-foot-high moun-tain of garbage rising from the landfill, theNew York Police Department has setup an evidence recovery operationknown simply as “The Hill.” There,as many as 30 investigators at atime, wearing full hazardous materi-als suits, perform the grim task ofsifting through the debris lookingfor the flight recorders of the twohijacked airplanes, human remains,and any belongings that can helpidentify the victims. Such finds arecatalogued for identification, andthe rest is landfilled.

One of the consequences of thecleanup effort is the constant flowof dump trucks, which adds to thealready heavy traffic of downtownManhattan and to the levels ofdiesel exhaust fumes in the neigh-borhood. “We already had a trafficproblem here, and now you can seethese trucks with their uncovered loadsgoing down our streets,” said neighborhoodresident Alicia Aguilar during a recent com-munity forum. To alleviate the truck trafficassociated with the cleanup effort and toallow easier access to remove debris to theStaten Island landfill, the U.S. Army Corpsof Engineers has ordered the dredging of anarea of the Hudson River that is near theWorld Trade Center site.

Some of the debris is being removed bybarge, but high truck traffic and use of diesel-powered machinery at the site continues.

Thurston, who has been monitoring con-centrations of air pollutants, has seen thatcarbon levels have been elevated in someinstances, “and these may come from

increased diesel combustion,” he says. Dieselcombustion and the soot that it producescan be a trigger for asthma attacks in thosewho have the disease.

Continuing Questions

The state of the science cannot possiblypredict all the possible long-term environ-mental health effects of this unprecedent-ed disaster. The science of risk assessmentis still limited, and it does not permit thefull recognition of all potential hazards.Communicating this uncertainty to

community residents who can still smell thefumes emanating from the disaster site is amajor challenge to regulatory agenciescharged with the enormous task of protecting

the public and allaying its fears. Although multiple layers of

local, state, and federal agencieshave converged upon the WorldTrade Center site to conductenvironmental assessments, mon-itor for occupational hazards,and sample the environment forfurther study, the result for com-munity members often may beconfusion and further questions.“There have been many lessonslearned during this process,”says William Muszynski, actingregional administrator for EPARegion 2. “We need to be pre-pared to give people relevantinformation in a simpler and[more] usable way.”

This sentiment is shared bymany in the affected communi-

ty who still ask whether it is safe to gohome. No one person or agency is fully pre-pared to answer that question. But as thenation’s political leaders work to protectAmerican citizens and prevent futureattacks, the environmental health commu-nity of scientists and officials continuesworking diligently to assess and minimizethe environmental health risks to bothrecovery workers and the public from theevents of September 11.

Luz Claudio

A 536 VOLUME 109 | NUMBER 11 | November 2001 • Environmental Health Perspectives

Focus • Environmental Aftermath

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Lt. Bill McGinn Memorial Lecture FundThe Mount Sinai Department of Community and Preventive Medicinein New York City has established the Lt. Bill McGinn Memorial LectureFund. McGinn was a leader of Rescue Squad 18 of the New York CityFire Department. He had collaborated with his wife, Anne Golden, anassistant professor of epidemiology in the Mount Sinai Departmentof Community and Preventive Medicine, in conducting epidemiolog-ic studies to assess how exposure to toxic chemicals produced in firescan affect the health of firefighters. Together, they sought to devel-op methods by which firefighters could protect their health and alsoimprove the safety of their work environment.

McGinn is described by colleagues as “the man who would climbstairs two steps at a time when responding to a fire in a building.” Hedied while responding to the September 11 attacks on the WorldTrade Center.

The fund will support an annual lecture series devoted to healthand safety topics of concern to emergency responders, including fire-fighters. The fund will also support other educational efforts relatedto firefighter safety, as well as to fire safety in general.

Donations to the Lt. Bill McGinn Memorial Lecture Fund can besent to the Lt. Bill McGinn Memorial Lecture Fund, Box 1049, 1 Gustave Levy Place, New York, NY 10029 USA; phone: 212-373-4940

In Memoriam:Kristin White

In the tragic events of 11 September 2001,we at EHP lost one of our own. KristinWhite, a freelance science writer from NewYork City, was killed in the crash of UnitedAirlines Flight 93 near Pittsburgh. Kristinbegan writing for EHP in our first year ofpublication as a monthly journal. Over theyears, she illuminated a range of topics forour readership with clarity and concise-ness. Of particular note are her investiga-tions into the environmental health effectsof the Midwestern floods of 1993, therevamping of the Clean Water and SafeDrinking Water Acts, and the health conse-quences to soldiers who served in thePersian Gulf War. Kristin was a consummateprofessional with a passion for environ-mental issues. We will miss our collabora-tions with her and her contribution to theenvironmental health sciences.

Hope survives. A firefighter makes his way through the headstones atTrinity Church Cemetery in lower Manhattan on his way back to work onthe city’s recovery.