HETA 91–0346–2572

FBI Academy

Quantico, Virginia

Michael E. Barsan

Aubrey Miller, M.D.

This Health Hazard Evaluation (HHE) report and any recommendations made herein are for the specific facility evaluated and may not be universally

applicable. Any recommendations made are not to be considered as final statements of NIOSH policy or of any agency or individual involved.

Additional HHE reports are available at http://www.cdc.gov/niosh/hhe/reports

This Health Hazard Evaluation (HHE) report and any recommendations made herein are for the specific facility evaluated and may not be universally

applicable. Any recommendations made are not to be considered as final statements of NIOSH policy or of any agency or individual involved.

Additional HHE reports are available at http://www.cdc.gov/niosh/hhe/reports

This Health Hazard Evaluation (HHE) report and any recommendations made herein are for the specific facility evaluated and may not be universally

applicable. Any recommendations made are not to be considered as final statements of NIOSH policy or of any agency or individual involved.

applicable. Any recommendations made are not to be considered as final statements of NIOSH policy or of any agency or individual involved.

Additional HHE reports are available at http://www.cdc.gov/niosh/hhe/reports
ii

PREFACE

The Hazard Evaluations and Technical Assistance Branch of NIOSH conducts field investigations of possible

health hazards in the workplace. These investigations are conducted under the authority of Section 20(a)(6)

of the Occupational Safety and Health Act of 1970, 29 U.S.C. 669(a)(6) which authorizes the Secretary of

Health and Human Services, following a written request from any employer or authorized representative of

employees, to determine whether any substance normally found in the place of employment has potentially

toxic effects in such concentrations as used or found.

The Hazard Evaluations and Technical Assistance Branch also provides, upon request, medical, nursing, and

industrial hygiene technical and consultative assistance (TA) to Federal, State, and local agencies; labor;

industry; and other groups or individuals to control occupational health hazards and to prevent related trauma

and disease. Mention of company names or products does not constitute endorsement by the National

Institute for Occupational Safety and Health.

ACKNOWLEDGMENTS AND AVAILABILITY OF REPORT

This report was prepared by Michael E. Barsan and Aubrey Miller, M.D. of the Hazard Evaluations and

Technical Assistance Branch, Division of Surveillance, Hazard Evaluations and Field Studies (DSHEFS).

Desktop publishing by Ellen E. Blythe.

Copies of this report have been sent to employee and management representatives at the FBI Academy and

the OSHA Regional Office. This report is not copyrighted and may be freely reproduced. Single copies of

this report will be available for a period of three years from the date of this report. To expedite your request,

include a self–addressed mailing label along with your written request to:

NIOSH Publications Office

4676 Columbia Parkway

Cincinnati, Ohio 45226

800–356–4674

After this time, copies may be purchased from the National Technical Information Service (NTIS) at 5825

Port Royal Road, Springfield, Virginia 22161. Information regarding the NTIS stock number may be

obtained from the NIOSH Publications Office at the Cincinnati address.

For the purpose of informing affected employees, copies of this report shall be posted by the

employer in a prominent place accessible to the employees for a period of 30 calendar days.
iii

Health Hazard Evaluation Report 91–0346–2572

FBI Academy

Quantico, Virginia

April 1996

Michael E. Barsan

Aubrey Miller, M.D., M.P.H.

SUMMARY

In July 1991, the National Institute for Occupational Safety and Health (NIOSH) received a request for

a Health Hazard Evaluation (HHE) from a management representative of the Federal Bureau of

Investigation (FBI) at the FBI Academy in Quantico, Virginia. The request concerned lead exposures

during firearms training and associated activities among range technicians, gunsmiths, and firing range

instructors. Additionally, the requestor was concerned about the potential for "take-home" lead

contamination of workers' vehicles and homes, and exposure of their families. Workers also expressed

concerns about work-related noise-induced hearing loss. 

In response to this request, NIOSH participated in a series of collaborative evaluations with the National

Center for Environmental Health (NCEH). The following report concerns the NIOSH evaluation of lead

exposures incurred by FBI employees during firearms training activities and associated use of the firing

ranges, and a review of audiometric testing for noise-induced hearing loss. 

In November and December 1991, NIOSH investigators conducted a walk-through survey of the FBI

Firearms Training Unit (FTU) firing ranges and related facilities and conducted: (1) air sampling for lead,

(2) qualitative evaluation of firing range ventilation systems using a smoke generator, (3) sampling of

carpets for lead dust in student and non-student dormitory rooms (rooms used by visiting law enforcement

officials not typically involved in firearms training), (4) medical interviews of FBI employees associated

with the FTU, and (5) review of blood lead and audiometric testing results for current FTU workers. 

The survey was designed to determine occupational lead exposures among FBI and Drug Enforcement

Agency (DEA) firing range instructors, gunsmiths, range technicians, and custodians. Sixty-one personal

breathing-zone (PBZ) and 30 area samples for airborne lead were collected. Personal sampling found that

firing range instructors' exposures ranged up to 51.7 micrograms per cubic meter (:g/m3

) (mean 12.4

:g/m3), range technicians' exposures ranged up to 2.7 :g/m3 (mean 0.6 :g/m3), and gunsmiths' exposures

ranged up to 4.5 :g/m3

 (mean 0.6 :g/m3). Custodians' exposures ranged from non-detectable to 220

:g/m3 during short-term cleaning of a large indoor range. 

Private medical interviews were conducted with 13 randomly selected workers (6 instructors, 2 range

technicians, 2 gunsmiths, and 3 custodians) associated with the FBI FTU. None of the interviews were

remarkable for any significant symptoms or health problems associated with the workplace lead exposures.

Records of blood lead levels (BLLs) for all current FBI instructors, range technicians, gunsmiths, and

custodians from 1989-1991 were reviewed. The mean BLL among instructors decreased from 14.6

micrograms per deciliter (:g/dl) in 1989 to 7.4 :g/dl in 1991. In comparison, there was no appreciable

reduction in mean BLL among gunsmiths and range technicians during this time period. Custodians, who
iv

were first tested in 1991, all had BLL of less than 4 :g/dl. Although the BLLs for workers were generally

below the U.S. Public Health Service goal of 25 :g/dl10 (only two were above 25 :g/dl), there are still

potential adverse health effects that have been associated with BLLs similar to those found in FTU

workers (i.e., small blood pressure elevations associated with lead levels as low as 10 :g/dl7

). 

A review of recent and baseline audiometric test results for 14 instructors and 1 range technician was

performed. Nine of the 15 had audiometric abnormalities that met the OSHA Standard Threshold Shift

criteria (i.e., changes relative to baseline of 10 dB or more in the average hearing level at 2000, 3000, and

4000 Hz). 

Carpet dust samples were collected in 14 FBI student dormitory rooms (third floor of the student

dormitory) and in 14 non–student dormitory rooms (second and third floor of an adjacent dormitory).

Student dormitory rooms had significantly higher lead levels than non–student dormitory rooms (means

of 214 and 65 :g respectively). This suggests that FBI students may be contaminating their living quarters

with lead.

A potential hazard from short-term overexposure to lead via inhalation existed at the FBI

Firearms Training Unit outdoor firing ranges at the time of the investigation. The direction of the

prevailing wind at the outdoor ranges was found to influence the extent of lead exposure. In

addition, a potential problem of "take-home" lead exposure of families of firearms instructors was

found. Review of audiometric test results suggests that workers may be at increased risk for

noise induced hearing loss. Recommendations for enhanced hearing protection, modifications

of the indoor firing range's ventilation system, and for safe use of all the ranges are offered at the

end of this report.

Keywords: SIC 9221 (Police Protection), indoor firing ranges, outdoor firing ranges, inorganic lead,

ventilation system design, engineering controls, para-occupational exposure, blood lead level, noise,

hearing loss
TABLE OF CONTENTS

Preface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ii

Acknowledgments and Availability of Report . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ii

Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . iii

Introduction ................................................................... 1

Background ................................................................... 1

Students' Range . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

Gunsmiths' Range . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

Outdoor Ranges ............................................................ 3

Custodians . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

Lead Exposure Program ......................................................3

Evaluation Design and Methods ....................................................4

Medical . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

Environmental . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

Dormitory Room Lead Dust Evaluation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

Evaluation Criteria . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

Lead . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

Lead in surface dust and soil ................................................6

Lead–childhood exposure .................................................7

Ventilation Principles for Evaluation of Indoor Firing Ranges ..........................7

Noise Induced Hearing Loss (NIHL) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

Medical Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

Medical Interviews . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

Blood Lead Testing Program . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

Hearing Conservation (Audiometric Testing) Program . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

Environmental Sampling Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

Lead Exposure Assessment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

Outdoor Firing Ranges . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

Qualitative Ventilation Assessment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

Students' Indoor Range . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

Gunsmiths' Indoor Range . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

Exhaust Fan Room . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

Linen Room . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

Dormitory Room Lead Dust Sampling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

Discussion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

Lead . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

Noise . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

Instructors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

Outdoor Ranges . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Indoor Ranges . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

Range Technicians . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

Gunsmiths . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

Custodians . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

Recommendations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Health Hazard Evaluation Report No. 91–0346 Page 1

INTRODUCTION

In July 1991, the National Institute for

Occupational Safety and Health (NIOSH)

received a request for a Health Hazard

Evaluation (HHE) from a management

representative of the Federal Bureau of

Investigation (FBI) at the FBI Training

Academy in Quantico, Virginia. NIOSH was

requested to evaluate lead exposures during

firearms training and associated activities among

range technicians, gunsmiths, and firing range

instructors. Additionally, the requestor was

concerned about the potential for "take-home"

lead contamination of workers' vehicles and

homes, and exposure of their families.

In November and December 1991, NIOSH

investigators conducted a walk-through survey

of the FBI Firearms Training Unit (FTU) firing

ranges and related facilities at the Academy. In

December 1991, NIOSH investigators

conducted an air-sampling survey to determine

airborne lead exposure to the firing range

personnel during their workday. Also during

this survey, a smoke generator was used to

evaluate the effectiveness of the ventilation

system at the indoor firing ranges. A review of

audiometric testing for noise-induced hearing

loss was also conducted in response to

employees’ concerns.

BACKGROUND

There were 16 full-time firearms instructors in

the Firearms Training Unit (FTU) who spent an

average of approximately 30 hours per week on

the firing ranges. The instructors conducted

firearms training sessions for the Federal Bureau

of Investigation (FBI) and Drug Enforcement

Agency (DEA) trainees at outdoor and indoor

firing ranges. A second indoor range was used

by gunsmiths to test-fire weapons. The FTU

also included nine full–time gunsmiths who testfired weapons, and five range technicians who

handled ammunition. At the time of this

investigation, there were eight trainee classes at

the FBI Academy, composed of 32 students

each. Each class goes through a 16–week

training period during which there are 28

firearms training sessions. Firearms training

sessions last about four hours. Hand washing

facilities were available for the 16 current

instructors (13 male and 3 female) in the FTU

range office. However, shower facilities were

available only for the male instructors. The

instructors reportedly rarely used the shower and

normally went home in the clothes that they

wore at the firing ranges. 

The FBI Academy had one indoor firing range

that was used for training (Figure 1), one indoor

range that was used for gun testing (Figure 1),

and seven outdoor firing ranges that were used

for training (Figure 2). The two indoor firing

ranges were located on the first floor of a

two–story, multi–use concrete block building.

The training indoor firing range had 23 shooting

booths for student training. Gunsmiths,

instructors, and other FBI agents also used the

range. The gun testing indoor range was large

enough for just one shooter at a time. In this

report, the larger firing range will be referred to

as the "students' range," and the smaller range

will be referred to as the "gunsmiths' range."

The term "downrange" in this report means

toward the bullet trap end of the range;

"uprange" means toward the shooting end of the

range. The directions "left" and "right" are

relative to a shooter facing downrange.

Figure 1 shows that the right wall of the

gunsmiths' range abutted the uprange wall of the

students' range. The ranges had common supply

and exhaust fans, and 100% of the range air was

exhausted after one pass. The supply fan and air

intake were adjacent to the left wall of the

students' range. As it entered the building,

supply air was pre–filtered by a 1–inch-thick

filter mounted upstream of the rain louvers

which covered the outside air intake. After

pre–filtering, air entered a plenum, which was in
Page 2 Health Hazard Evaluation Report No. 91–0346

the same room as the supply fan. This plenum

contained a roll filter and heating coils, but there

were no provisions for cooling the air. Both the

pre–filter and roll filter were made of materials

estimated to have a filter efficiency of less than

20%, according to the American Society of

Heating, Ventilating, and Air–Conditioning

Engineers (ASHRAE). After passing through

the filters and heating coils in the plenum, the air

entered the supply fan room and was distributed

via ducts to the indoor ranges.

The exhaust fan system was separate from the

supply fan system. The exhaust fan was in a

room adjacent to the right side of the bullet trap

area of the students' range. The room served as

the fan plenum. Ducts from both indoor ranges

ran through the walls of the room and terminated

at the inside wall surface. These ducts were not

directly connected to the exhaust fan, which

removed air from the room through an exterior

wall. Air was not filtered as it entered the

exhaust fan room or before it was exhausted

outside.

Students' Range

The students' range was approximately 100 feet

by 100 feet and had 23 shooting booths. Due to

structural columns uprange of the booths, there

were gaps between booths 6 and 7, 13 and 14,

and 20 and 21. There was an additional gap

between Booth 1 and the left wall of the range.

The ceiling height in the students' range was 7

feet for the area between the uprange wall and

the firing line, and 8 feet for the first 10 feet

downrange of the firing line. The ceiling height

for the rest of the range was about 12 feet.

Bullet deflectors, suspended from the ceiling

downrange of the firing line, provided protection

for lighting and ductwork. The range had

double door entrances on each end of the

uprange wall.

Air was supplied to the students' range through

an uprange air wall, approximately 13 feet from

the uprange end of the booths. This air wall was

constructed of perforated metal panels mounted

in an iron framework. The panels had a pattern

of 1⁄4–inch diameter holes on 1⁄2–inch vertical and

horizontal centers, creating an approximate 15%

free area of the wall (percentage of the total wall

which is holes). The air wall was about 3 feet

from the uprange endwall, creating a plenum in

the space between the air wall and the end wall.

Air was supplied to the air wall plenum through

the ceiling via 23 branch ducts connected to a

single main duct. Each duct opening had turning

vanes mounted in the duct just upstream of the

connection to the air wall plenum. Access to

the air wall plenum was through a door in a

room outside the gunsmiths' range.

The entrances to the students' range were also air

wall plenums. The outer doors of the entrances

were metal–clad double doors, and the inner

doors were double metal–frame doors with

perforated metal panels that were the same

design as the rest of the air wall. Each door

plenum had a supply air branch duct in the

ceiling that was connected to the same main duct

supplying the rest of the air wall. The duct

outlets had diffusers with moveable louvers.

The design air flow for the students' range was

43,900 cubic feet per minute (cfm). Average

velocity through the booths using this flow rate,

assuming a ceiling height of 8 feet and a room

width of 100 feet, was approximately 55 feet per

minute (fpm).

Exhaust air was removed from the range at two

locations: approximately midway from the

firing line to the bullet trap and at the bullet trap.

Design air flow specifications were 8,000 cfm

for the midrange exhaust and 40,000 cfm for the

bullet trap exhaust. The midrange exhaust

system consisted of ten 12-inch by 12-inch inlets

approximately 10 feet above the floor. The

inlets had single–blade dampers and hardware

cloth covering the opening. The bullet trap

exhaust consisted of twenty 18-inch by 18-inch

inlets with single–blade dampers and hardware

cloth coverings. The inlets for the trap exhaust

system were directly above the trap.
Health Hazard Evaluation Report No. 91–0346 Page 3

The bullet trap was designed to direct spent

bullets behind the trap. Spent bullets in the trap

and lead impacted on the trap were cleaned

manually. Access to the area behind the trap

was through a door in the exhaust fan room.

Gunsmiths' Range

The gunsmiths' range was approximately 8 feet

wide, 8 feet high, and 60 feet long. Instead of a

shooting booth, there was a desk that is

used when firing weapons. During firing, the

gunsmith sat at the desk and rested his arms on

a leather–covered weighted pillow which sat on

a wooden box on the desk. The range had a

single entrance through a door in the uprange

wall. The downrange end of the desk was

approximately 10 feet from the uprange wall.

Air was supplied to the gunsmiths' range through

four in–line, ceiling mounted registers near the

uprange endwall. Two of the registers were

2 feet by 2 feet, and the other two were 6 inches

by 2 feet. All of the registers had opposed–blade

dampers, and all but one had adjustable louvers.

The registers covered nearly the entire width of

the range.

The design exhaust flow for the gunsmiths'

range was 4,050 cfm. Exhaust air was removed

from the range by a single midrange exhaust and

a single trap exhaust inlet similar in design to

those in the students' range. The air flow

distribution for the two inlets was not available.

Outdoor Ranges

Of the outdoor firing ranges, Fields 1, 2, and 3

were used most often by the FBI instructors.

These three ranges were each about 100 yards

wide by 60 yards long, with asphalt shooting

lines at 7, 15, 25, 50, and 60 yards from the

target line. The ranges were covered on three

sides by dirt berms approximately 15 feet high.

Each of these ranges could accommodate

80 shooters at one time. The electric range was

about 45 yards wide by 25 yards long and had

dirt berms similar to the other ranges. This

range had moving targets and did not

accommodate many shooters at one time.

During this investigation, two students at a time

used the electric range. Fields 1, 2, 3, and the

electric range had a control tower in which one

of the instructors sat during the firing session. In

the control tower, the instructor used the public

address system to give commands for shooting

and operated the electric target holders.

The stress obstacle course (SOC) was

approximately 100 yards long and could

accommodate two shooters at one time. The

two shooters traversed the course together,

climbing obstacles and periodically shooting at

steel targets located at various points along the

course. The instructors walked along behind the

shooters throughout the course. The SOC,

which was located along the forest northwest of

the other outdoor ranges, did not have dirt berms

around it. 

Custodians

There were three custodians responsible for

cleaning the large indoor firing range about two

times per week. This procedure consisted of

using a dry broom to sweep the lead dust and

other debris on the cement floor into piles

downrange of the firing line. The piles were

then collected using a high efficiency

particulate air filter (HEPA) vacuum. The

custodians also vacuumed the carpeting uprange

of the firing line.

Lead Exposure Program

According to the present FBI policies, blood

lead testing is performed every 6 months on all

instructors, range technicians, and gunsmiths.

Custodians, who were added to the blood lead

testing program in 1991, undergo testing on an

annual basis. All instructors are required to

wear uniforms while working. However,
Page 4 Health Hazard Evaluation Report No. 91–0346

instructors and range technicians are not

required to routinely wear any specific

protective clothing. Gunsmiths are provided

protective aprons for routine use in the gun vault

and indoor firing ranges. Custodians are

required by the FBI to wear TyvekTM suits with

respiratory protection when performing any

clean–up operations within the indoor firing

range areas that had a significant potential for

lead exposures, such as sweeping the downrange

portion of the firing range.

EVALUATION DESIGN

AND METHODS

Medical

Private medical interviews were conducted with

13 workers randomly selected from a list of

41 employees who worked in the indoor firing

ranges and were available on the days of the

survey. Six of the 16 FBI instructors, 2 of the 6

range technicians, 2 of the 13 gunsmiths, and 3

of the 6 custodians were interviewed.

Information concerning possible health

problems, symptoms associated with excess lead

exposures, work practices, and use of personal

protective equipment was gathered during the

medical interviews. To determine the extent of

workplace lead exposures, records of blood lead

levels (BLLs) from 1989 - 1991 for the 41

current FBI instructors, range technicians,

gunsmiths, and custodians were evaluated.

Additionally, an evaluation for potential noiseinduced hearing loss (NIHL) was conducted

because of worker concerns about noise

exposures during the firing of weapons. The

NIHL evaluation included specific questioning

of workers during medical interviews and a

review of available baseline and most recent

audiograms for instructors, range technicians,

and gunsmiths. The blood lead and audiometric

testing results were received and reviewed by

NIOSH after the site visits.

Environmental

To assess lead exposures of firing range

personnel (not students), personal breathing

zone (PBZ) and area air samples for airborne

lead were collected during seven different

training sessions at six different firing ranges.

At the outdoor ranges (Fields 1, 2, and 3, the

electric range, and the SOC) PBZ air samples

were collected from all the instructors, and area

air samples were collected behind the firing line

near the control tower. At the SOC, the area

sample was collected near the beginning of the

course.

To assess potential lead exposures to firing

range personnel and effectiveness of the

ventilation system in the indoor firing ranges,

area air samples were collected throughout the

range and in the ventilation system. Initially, air

samples were collected while the ventilation

system was running but the range was not in use.

Air samples were then collected from the same

locations with the ventilation system operating

while the range was used for a firearms

qualifying session. Because it was a qualifying

session, we did not ask any of the shooters (FBI

trainees) to wear personal sampling pumps.

While the indoor range was being used for this

qualification session, an area air sample was

collected in the linen room adjacent to the firing

range. During a different sampling period, a

PBZ air sample was collected from a shooter

using the indoor range for nearly 11⁄2 hours.

PBZ air samples were collected from three

custodians during short-term cleaning (<1 hour)

of the indoor range after it had been used for a

few days. PBZ air samples were collected from

all of the gunsmiths and range technicians for

the entire day during each day of the survey. 

All air samples were collected and analyzed

according to NIOSH method 7300.1

 The
Health Hazard Evaluation Report No. 91–0346 Page 5

analytical limit of detection (LOD) for lead on

all of the air samples was 1.0 micrograms (:g)

per sample, which equates to a minimum

detectable concentration (MDC) of 2.9

micrograms per cubic meter (:g/m3

) for a

350–liter sample. The limit of

quantitation (LOQ) for lead was 3.3 :g per

sample, which equates to a minimum

quantifiable concentration (MQC) of 9.4 :g/m3

for a 350–liter sample. 

Airflow patterns at the indoor firing range were

observed using a Roscoe Fog Machine (model

number 1500), which generated a visible,

non–toxic "smoke." In the students' range,

smoke was released in each of the 23 booths

from the booth's shelf level and at the floor level

directly beneath the shelf. In addition, smoke

was released at the floor level in the gaps

between booths 6 and 7, 13 and 14, and 20 and

21. In the gunsmiths' range, smoke was released

on top of the desk and on the floor downrange of

the desk.

At each position, the smoke was observed for

about one minute to determine whether the air

flowed through the booths and downrange as

designed. Any back–flow through the booths

and downrange was noted, and further testing

was performed between the air wall and the

booths, and downrange of the booths to identify

the cause of any back–flow. This additional

testing was performed at various non–specific

distances and elevations.

Dormitory Room Lead Dust

Evaluation

Since student trainees lived in the dormitory

rooms during their 16-week training periods, it

was expected the evaluation of room lead dust

levels would show the potential for "take-home"

lead contamination from FTU facilities to the

private homes of FBI firearms instructors,

gunsmiths, range technicians, and custodians.

To assess the extent of lead contamination in the

FBI student dormitory rooms, carpet dust

samples were collected from the carpet in 14

student dormitory rooms (on the third floor of

the student dormitory) and in 14 non–student

dorm rooms (on the second and third floors of an

adjacent dormitory). Non-students would not be

likely to use the firing ranges. Samples were

collected on mixed cellulose ester filters in

cassettes connected to personal air sampling

pumps calibrated to a flow rate of 2.0 liters per

minute. The cassettes were connected to the

pumps with a short piece of TygonTM tubing.

The collection attachment was a piece of

stainless steel tubing crimped on one end to

form an elongated opening.2

 Dust samples were

collected from the area inside a 25 x 25

centimeter plexiglass template that was placed

on the floor in the rooms. The samples were

analyzed according to NIOSH method 7300.1

Two samples were collected in each room:

centered in the hallway door two feet inside the

room, and adjacent to the center of the

bathroom door.

EVALUATION

CRITERIA

Lead

People have used lead since ancient times

because of its useful properties, and it was the

ancient Romans and Greeks who first discovered

its toxic effects. Workplace exposure to lead

occurs by inhalation of dust and fume and

ingestion of lead-contaminated dust on surfaces.

Once absorbed, lead accumulates in the soft

tissues and bones. A person's BLL is the best

indication of recent exposure to, and current

absorption of lead. Lead is stored in the bones

for decades, and health effects may occur long
Page 6 Health Hazard Evaluation Report No. 91–0346

after the initial exposure as the bones release

lead in the body. 

Numerous studies have documented toxic

effects of lead on the nervous system,

reproductive system, kidneys, blood-forming

system and the digestive system.3,4,5,6,7 Lead has

been shown to be an animal carcinogen, but

there is not yet conclusive evidence that lead

exposure causes cancer in humans. Lead

poisoning can occur because of chronic

exposure or after a short period of very high

exposure. The frequency and severity of

symptoms associated with lead exposure

generally increase with the BLL. Many of the

symptoms of excessive lead exposure can easily

be confused with other causes; these include

weakness, excessive tiredness, irritability,

constipation, anorexia, abdominal discomfort

(colic), and fine tremors.3,4,5,6,7 

The Occupational Safety and Health

Administration (OSHA) general industry lead

standard (29 CFR 1910.1025 [1978]) established

a Permissible Exposure Limit (PEL) of 50

:g/m3 and an action level of 30 :g/m3 (both 8-

hour time–weighted averages [TWAs]).8

 The

OSHA standard requires adjusting PEL for work

shifts longer than 8 hours, medical monitoring

for employees exposed to airborne lead at or

above the action level, medical removal of

employees whose average BLL is

50 micrograms per deciliter (:g/dl) or greater,

and economic protection for medically removed

workers. Medically removed workers cannot

return to jobs involving lead exposure until their

BLL is below 40 :g/dl. The American

Conference of Governmental Industrial

Hygienists (ACGIH) threshold limit value

(TLVTM) for lead is 50 :g/m3

 (8-hour TWA),

with a BEI of 30 :g/dl. ACGIH has also

designated lead as an animal carcinogen and

recommends that “...worker exposures by all

routes be carefully controlled to levels as low as

possible below the TLV.”9

 The U.S. Public

Health Service has establish a national public

health goal to eliminate all occupational

exposures that result in BLLs greater than 25

:g/dl by the year 2000.10 NIOSH supports the

Public Health Service goal and recommends that

to minimize the risk of adverse health effects,

employers and workers should continually strive

to reduce workplace lead exposures.

Health studies indicate that the OSHA lead

standards noted above are not protective for all

the known health effects of lead. Studies of

adults have found neurological symptoms with

BLLs of 40 to 60 :g/dl, decreased fertility in

men at BLLs as low as 40 :g/dl, and increases in

blood pressure with no apparent threshold to

BLLs of less than 10 :g/dl.7

 Fetal exposure to

lead is associated with reduced gestational age,

birth weight, and early mental development with

maternal BLLs as low as 10 to 15 :g/dl.7

Lead exposure reduction efforts over the past

two decades in the U.S. have resulted in a

significant drop in lead exposures. From 1976

and 1991 the mean adult BLL dropped from

13.1 to 3.0 :g/dl, and in 1991 more than 98

percent of adults had a BLL less than 15 :g/dl.11

Occupational lead exposures of public health

concern continue to occur, however. For

example, in 1994 the NIOSH Adult Blood Lead

Epidemiology and Surveillance program

received reports for 12,137 adults with elevated

BLLs $25 :g/dl from 23 participating states.

In homes with a family member occupationally

exposed to lead, care must be taken to prevent

"take home" of lead. Lead may be carried into

the home on clothing, skin, or hair, or from

vehicles. High BLLs in resident children, and

elevated concentrations of lead in the house

dust, have been found in the homes of leadexposed workers.12 Children of persons who

work in areas of high lead exposure should

receive a BLL test.

Lead in surface dust and soil

Lead is commonly found in U.S. urban dust and

soil due to the past use of lead in gasoline and

paints, and also industrial emissions. Lead-
Health Hazard Evaluation Report No. 91–0346 Page 7

contaminated surface dust and soil represent

potential sources of lead exposure, particularly

for young children. Lead exposure may occur

either by direct hand-to-mouth contact, or

indirectly from hand-to-mouth contact with

contaminated clothing, cigarettes, or food.

Previous studies have found a significant

correlation between resident children’s BLLs

and house dust lead levels.13 There is no federal

standard which provides a permissible limit for

lead contamination of surfaces in occupational

settings. As required by Section 403 of the

Toxic Substances Control Act (as amended in

1992) the Environmental Protection Agency

(EPA) is in the process of developing healthbased residential standards for lead in dust,

paint, and soil. 

EPA currently recommends the following

clearance levels for surface lead loading be met

after residential lead abatement or interim

control activities: uncarpeted floors, 100

micrograms per square foot (:g/ft2

); interior

window sills, 500 :g/ft2

, and window wells, 800

:g/ft2.

14 These levels have been established as

achievable through lead abatement and interim

control activities, and they are not based on

projected health effects associated with specific

surface dust levels. 

EPA currently recommends a strategy of scaled

responses to soil lead contamination, depending

upon lead concentrations and site-specific

factors. When lead concentrations exceed 400

ppm in bare soil, EPA recommends further

evaluation and exposure reduction activities be

undertaken, appropriate to the site-specific level

of risk. If soil lead concentrations exceed 5000

ppm, EPA recommends permanent abatement of

contaminated soil.14

Lead–childhood exposure 

The adverse effects of lead on children and

fetuses include decreases in intelligence and

brain development, developmental delays,

behavioral disturbances, decreased stature,

anemia, decreased gestational weight and age,

and miscarriage or stillbirth. Lead exposure is

especially devastating to fetuses and young

children due to potentially irreversible toxic

effects on the developing brain and nervous

system.7

No threshold has been identified for the harmful

effects of lead in children; the Centers for

Disease Control and Prevention (CDC) currently

recommends a multitier approach to defining

and preventing childhood lead poisoning, based

on BLL screening.15 The BLLs and

corresponding actions which CDC has

recommended are: $10 :g/dl, community

prevention activities; $15 :g/dl, individual case

management including nutritional and

educational interventions and more frequent

screening; $20 :g/dl, medical evaluation,

environmental investigation and remediation.

Additionally, environmental investigation and

remediation are recommended for BLLs of

15–19, if such levels persist. 

Overall, U.S. population blood lead levels have

declined since 1976. A recent national survey

found that the geometric mean BLL for children

ages 1–11 ranged from 2.5–4.1 :g/dl, with the

highest mean BLL among children aged 1–2

years.16 However, it was estimated from the

survey that 8.9% of U.S. children under 6 years,

or about 1.7 million children, have elevated

BLLs ($ 10 :g/dl).

Ventilation Principles for

Evaluation of Indoor Firing

Ranges

Ideally, the air flow in indoor firing ranges

should be laminar and horizontal from the air

wall to downrange of the booths. A horizontal,

laminar air flow pattern will carry contaminated

air away from the shooter toward the exhaust
Page 8 Health Hazard Evaluation Report No. 91–0346

system. A moderate rise in the direction of air

movement between the air wall and the booths is

tolerable, as long as eddies which cause

back–flow through the booths do not occur. Air

which flows back from downrange through the

booths is undesirable because back–flowing air

could recirculate lead fume from downrange to

the shooter's breathing zone. Shooters can be

exposed to lead fume in the back–flowing air

even after shooting has stopped.

Noise Induced Hearing Loss

(NIHL)

Noise-induced loss of hearing is an irreversible,

sensorineural condition that progresses with

exposure. Although hearing ability declines

with age (presbycusis) in all populations,

exposure to noise produces hearing loss greater

than that resulting from the natural aging

process. This noise-induced loss is caused by

damage to nerve cells of the inner ear (cochlea)

and, unlike some conductive hearing disorders,

cannot be treated medically.17 While loss of

hearing may result from a single exposure to a

very brief impulse noise or explosion, such

traumatic losses are rare. In most cases, noiseinduced hearing loss is insidious. Typically, it

begins to develop at 4000 or 6000 Hertz (Hz)

(the hearing range is 20 Hz to 20000 Hz) and

spreads to lower and higher frequencies. Often,

material impairment has occurred before the

condition is clearly recognized. Such

impairment is usually severe enough to

permanently affect a person's ability to hear and

understand speech under everyday conditions.

Although the primary frequencies of human

speech range from 200 Hz to 2000 Hz, research

has shown that the consonant sounds, which

enable people to distinguish words such as "fish"

from "fist," have still higher frequency

components.18

The A-weighted decibel [dB(A)] is the preferred

unit for measuring sound levels to assess worker

noise exposures. The decibel unit is

dimensionless, and represents the logarithmic

relationship of the measured sound pressure

level to an arbitrary reference sound pressure

(20 micropascals, the normal threshold of human

hearing at a frequency of 1000 Hz). Decibel

units are used because of the very large range of

sound pressure levels which are audible to the

human ear. The dB(A) scale is weighted to

approximate the sensory response of the human

ear to sound frequencies. Because the dB(A)

scale is logarithmic, increases of 3 dBA, 10

dBA, and 20 dBA represent a doubling, tenfold

increase, and 100-fold increase of sound energy,

respectively. It should be noted that noise

exposures expressed in decibels cannot be

averaged by taking the simple arithmetic mean.

The OSHA standard for occupational exposure

to noise (29 CFR 1910.95)19 specifies a

maximum PEL of 90 dB(A)-slow response for a

duration of eight hours per day. The regulation,

in calculating the PEL, uses a 5 dB

time/intensity trading relationship, or exchange

rate. This means that when a person is exposed

to noise levels of 95 dB(A), the amount of time

allowed at this exposure level must be cut in half

in order to be within OSHA's PEL. Conversely,

a person exposed to 85 dB(A) is allowed twice

as much time at this level (16 hours) and is

within his daily PEL. NIOSH, in its Criteria for

a Recommended Standard,20 proposed an

exposure limit of 85 dB(A) for 8 hours, 5 dB

less than the OSHA standard. The NIOSH 1972

criteria document also used a 5 dB time/intensity

trading relationship in calculating exposure

limits. However, NIOSH changed its official

recommendation for an exchange rate of 5 dB to

3 dB in 1995.21 The ACGIH also changed its

TLV in 1994 to a more protective 85 dB(A) for

an 8-hour exposure, with the stipulation that a 3

dB exchange rate be used to calculate timevarying noise exposures.22 Thus, a worker can

be exposed to 85 dB(A) for 8 hours, but to only

88 dB(A) for 4 hours or 91 dB(A) for 2 hours. 

Time-weighted average (TWA) noise limits as a

function of exposure duration are shown as
Health Hazard Evaluation Report No. 91–0346 Page 9

follows:

Sound Level dB(A) 

Duration of

 Exposure

(hrs/day)

ACGIH /

NIOSH OSHA

16 82 85

8 85 90

4 88 95

2 91 100 

1 94 105 

1/2 97 110 

1/4 100 115*

1/8 103 ---

1/16 106 

1/32 109 

1/64 112 

1/128 115*

*** **

* No exposure to continuous or

intermittent noise in excess of

115 dB(A).

** Exposure to impulsive or impact

noise should not exceed 140 dB

peak sound pressure level.

*** No exposure to continuous,

intermittent, or impact noise in

excess of a peak C-weighted level

of 140 dB.

The duration and sound level intensities can be

combined to calculate a worker's daily noise

dose according to the formula: 

Dose = 100 X (C1/T1 + C2/T2 + ... +

Cn/Tn ),

where Cn indicates the total time of exposure at

a specific noise level and Tn indicates the

reference duration for that level as given in the

above table. During any 24-hour period, a

worker is allowed up to 100% of his daily noise

dose. Doses greater than 100% are in excess of

the evaluation criteria.

The OSHA regulation has an additional action

level (AL) of 85 dB(A) which stipulates that an

employer shall administer a continuing, effective

hearing conservation program when the TWA

value exceeds the AL. The program must

include monitoring, employee notification,

observation, an audiometric testing program,

hearing protectors, training programs, and

recordkeeping requirements. All of these

stipulations are included in 29 CFR 1910.95,

paragraphs (c) through (o).

The OSHA noise standard also states that when

workers are exposed to noise levels in excess of

the OSHA PEL of 90 dB(A), feasible

engineering or administrative controls shall be

implemented to reduce the workers' exposure

levels. Also, a continuing, effective hearing

conservation program shall be implemented.

RESULTS

Medical Results

Medical Interviews

Private medical interviews were conducted with

13 FBI employees (6 instructors, 3 custodians,

2 gunsmiths, and 2 range technicians). Of those

interviewed, five of the six instructors and all

gunsmiths and range technicians were male. All

three of the interviewed custodians were female.

The instructors were older than the other worker

groups, with an average age of 44 years (range

38–48), versus an average age of 38 years (range

30–44) for the other work groups combined.

Compared to other groups, instructors were also

employed longer at the FBI, averaging 13 years,

while the other work groups combined averaged

4 years. Only two of the interviewed workers

(both gunsmiths) reported any notable history of

non–work related lead exposures. 
Page 10 Health Hazard Evaluation Report No. 91–0346

Medical interviews revealed only complaints of

occasional headaches experienced by two

instructors when firing guns on the indoor

ranges. None of the interviewed employees

reported any recent or past history of symptoms

associated with their jobs, including any

symptoms which might be associated with

elevated lead exposures. While none of the

workers reported any history of work-related

symptoms, a number of workers expressed

concerns about NIHL and reproductive

problems potentially related to their

occupational exposures. All interviewed

gunsmiths voiced concern about potential lead

exposures during routine unprotected cleaning

and sweeping of the small indoor firing range. 

The average reported durations of potential

occupational exposure to lead differed among

the work groups. The average reported periods

of potential work-related lead exposures were

approximately 22 hours per week (5 hours per

day) for instructors and gunsmiths, 16 hours per

week (3 hours per day) for range technicians,

and 6 hours per week (1 hour per day) for

custodians. Of the 13 workers interviewed, 31%

(4) reported eating or drinking and 15% (2)

reported smoking, in areas (i.e., indoor ranges,

weapon cleaning areas) with potential lead

exposures. Seventy-seven percent (10) of the

interviewed workers reported that they

consistently washed their hands after lead

exposures, and 15% (2) reported showering at

work prior to going home. All instructors

reported wearing uniforms between home and

work and laundering their uniforms at home.

Gunsmiths and range technicians all reported

wearing aprons or coveralls over their street

clothes while working and frequently washed

these protective clothes at home. Custodians

reported wearing full length TyvekTM suits

during clean-up of all indoor firing ranges and

disposing of the suits prior to leaving the area. 

All workers reported wearing eye and hearing

protection when firing weapons or working near

active firing ranges.

Blood Lead Testing Program

Table 1 summarizes the 1989—1991 BLL

results of the 41 workers (instructors, range

technicians, gunsmiths, and custodians)

employed at the time of the NIOSH evaluation.

Evaluation of blood lead test results for

instructors and gunsmiths revealed a marked

increase in the number of workers who

participated in the BLL testing program from

1990 to 1991. Only six instructors underwent

annual BLL testing in both 1990 and 1991. The

mean BLL among these six instructors fell from

13.5 to 7.7 :g/dl. In comparison, there was no

appreciable reduction in BLLs among gunsmiths

and range technicians during this time period.

As of 1991, the mean BLL of gunsmiths

continued to be about 12 :g/dl. As of 1991, the

mean BLL of range technicians was 13.6 :g/dl,

and all custodians, who were first tested in 1991,

had BLLs of less than 4 :g/dl. 

Hearing Conservation

(Audiometric Testing) Program

The baseline and the most recent audiometric

testing results were available for 14 of the 16

current FBI instructors. Evaluation of these

audiograms revealed hearing losses that met the

OSHA Standard Threshold Shift (STS) criterion

(i.e., changes relative to baseline of 10 dB or

more in the average hearing level at 2000, 3000,

and 4000 Hz) in 64% (9 of 14) of the instructors

tested. Audiometric testing results were only

available for one of the six current range

technicians, and this worker's results also met

the OSHA STS criterion. There were no

complete sets of recent and baseline audiometric

testing results for the gunsmiths currently

employed in the FTU. 
Health Hazard Evaluation Report No. 91–0346 Page 11

Environmental Sampling Results

Lead Exposure Assessment

Outdoor Firing Ranges

Presented in Table 2 are the results of PBZ and area

air sampling results for airborne lead collected at

Field 2, an outdoor range, during a 4–hour training

session. The only sample that contained a detectable

amount of lead (5.1 :g/m3

) was the PBZ sample for

FBI Instructor C. Lead was not detected on the PBZ

sample for the control tower operator (FBI Instructor

F). Wind direction during this session was

predominantly downrange. 

Table 3 presents the results of PBZ and area air

sampling for airborne lead at Field 2 during a 3–hour

training session. The only sample on which lead was

not detected was for FBI Instructor D, who was in the

control tower for the duration of the training session.

Airborne PBZ lead concentrations for the instructors

at the firing line ranged from 15.2 to 51.7 :g/m3

(mean 30.7 :g/m3). The area sample for this training

session was collected next to a telephone pole near the

control tower. This sample revealed an airborne lead

concentration of 2.4 :g/m3

. Wind direction during

this session was variable, with no clearly predominant

wind direction.

Presented in Table 4 are the results of PBZ and area

air sampling for airborne lead during a 31⁄2–hour

training session at Field 1. The only sample on which

lead was not detected was for FBI Instructor M,

who was in the control tower for the duration of the

training session. Airborne PBZ lead concentrations

for the instructors at the firing line ranged from 5.1 to

10.0 :g/m3

 with a mean of 6.8 :g/m3. The area

sample for this training session was collected next to

a telephone pole near the control tower. This sample

revealed an airborne lead concentration of 2.0 :g/m3

.

Wind direction during this session was variable,

with no clearly predominant wind direction.

Table 5 presents the results of PBZ and

area air sampling for airborne lead at

Field 3 during a 3–hour training session.

The only sample on which lead was not

detected was for the area sample, which

was collected next to a telephone pole near

the control tower. Airborne PBZ lead

concentrations for the DEA Instructors at

the firing line ranged from 6.0 to 17.4

: g/m 3 with a mean of

11.5 :g/m3

. Wind direction during this

session was variable, with no clearly

predominant wind direction.

Table 6 presents the results of PBZ and

area air sampling for lead at the Electric

Range and at the SOC. At the Electric

Range, lead was detected on only one

of the FBI Instructor's PBZ samples, giving

an airborne lead concentration of

4.9 :g/m3

. The other instructor at the

Electric Range (FBI Instructor N) was in

the control tower for the duration of the

training session. The PBZ airborne lead

concentrations for the two FBI instructors

at the SOC were 29.8 and 30.2 :g/m3

.

Lead was not detected on the area sample

at the SOC, which was collected behind

the start of the course. During the session

at the Electric Range, wind direction was

predominantly downrange; wind direction

measurements were not available from the

SOC.

Indoor Firing Ranges

Table 7 presents the results of area air

samples collected at the students' firing

range. Samples were collected just outside

the air intake of the indoor range,

just inside the intake, in the intake plenum,

and behind the pegboard through which air

passes to enter the firing range. In the

range itself, area air samples were

collected on the control table, at two of the

firing stations (#14 and #17), and at one of

the down–range pillars. Two other area air
Page 12 Health Hazard Evaluation Report No. 91–0346

samples were collected in the room that houses the

exhaust fan which pulls range air outside the building,

and outside the building near the exhaust air grates.

The top half of Table 7 presents results from air

samples collected at the locations described above

while the range was not in use. The bottom half of

Table 7 presents results of air samples collected from

these same locations while the range was being used

for a qualification shooting session. Lead was

detected in the exhaust fan room and just outside the

exhaust vent during the sampling period in which the

range was not in use. These concentrations were 2.8

and 22.7 :g/m3

, respectively. During the sampling

period while the range was in use, airborne lead

concentrations in the exhaust fan room and just

outside the exhaust vent rose to 338.2 and

186.6 :g/m3

, respectively. During the latter session,

an airborne lead concentration of 145.1 :g/m3

 was

measured at a pillar downrange of the firing line.

Lead was not detected on any of the other samples

collected in the range or the ventilation system during

either of these two sample periods. The range

ventilation system was operating during both

sampling periods.

Presented in Table 8 are the results of PBZ air

samples for lead collected from the range technicians

on two different days; low exposures were detected

(2.2, 2.6, and 2.7 :g/m3

).

Table 9 presents the results of PBZ air samples for

lead collected from the Gunsmiths during two

different days. Also presented are area sample results

that were collected just above the firing table in the

gunsmiths' firing range. On the first day of sampling,

lead was detected on just three of the nine PBZ air

samples, showing concentrations of 2.0, 3.8, and 4.5

:g/m3. On the second day, lead

was detected on only

one PBZ sample, revealing an airborne

concentration

of 1.1 :g/m3

. The area air sample in the

gunsmiths'

firing range showed an airborne lead

concentration of

4.6 :g/m3

 on the first day, and 1.0 :g/m3

on the

second day. 

Table 10 presents PBZ air sampling results

for a FBI

Hostage Rescue Team (HRT) agent who

fired 182

rounds in the Students' Indoor Range

during a period of about 11⁄2 hours.

Throughout the same day, including the

HRT agent's firing session, an area sample

for airborne lead was collected in the linen

room adjacent to the firing range and the

exhaust fan room. Lead was not detected

on either the PBZ or the area sample.

Presented in Table 11 are results of PBZ

sampling for airborne lead collected

from three Custodians who cleaned the

Students' Indoor Range for nearly an hour.

The airborne lead concentrations for

Custodians A and B were 127.5 and

220.0 :g/m3

, respectively. Custodian B

used a dry push–broom to sweep debris

into a pile, and Custodian A used a high

efficiency particulate air (HEPA) vacuum

to remove the debris. Lead was not

detected on the PBZ sample for Custodian

C, who vacuumed the carpet behind the

firing line.

Lead was not detected on any of the field

blanks collected for quality control

purposes during this evaluation.

Qualitative Ventilation Assessment

Students' Indoor Range

Observations made while using the smoke generator

revealed horizontal air movement with no back–flow

in 12 shooting booths (2, 3, 4, 5, 10, 11, 16, 17, 18,

19, 20, and 21), while six booths (1, 6, 7, 8, 9, and
Health Hazard Evaluation Report No. 91–0346 Page 13

12) had irregular air movement across the upper part

of the booths, with little to no backflow. The air

flow tests revealed that with a person posing in a

standing shooting position in a booth, the shooter's

wake could induce contaminated air into the

breathing zone. Increased laminar air flow through

these booths with improved top-to-bottom

distribution of the air should provide more even air

flow across the entire booth cross section, which

would reduce irregular air movement and improve

ventilation efficiency. 

Minor back–flow occurred at three booths (13, 14,

and 15), and between booths 13 and 14 at ceiling

level. Smoke released in the booths moved

downrange and rose to the ceiling a few feet

downrange. Intermittently, this downrange smoke

would flow back along the ceiling across the firing

line a few feet behind the shooters. The smoke then

moved through the same booths and was drawn

downrange. 

Smoke testing uprange of the booths revealed that air

exiting the air wall tended to move toward the right

instead of moving straight downrange, creating a

horizontal eddy behind the line. The intermittent

nature of the back–flow in the booths could be

caused by this eddy. A probable explanation for the

movement of air exiting the air wall is that the

plenum behind the air wall was used for storage of

various boxed materials. Some of the boxes were

stacked within six inches of the plenum perforated

wall. Also, one of the plenum supply ducts did not

have turning vanes to direct supply air. The missing

vanes could affect the air flow pattern behind the

wall and possibly the air flow distribution for all of

the supply ducts. The materials inside the plenum

and the possible uneven supply air flow distribution

could affect the distribution and pattern of air

coming from the air wall into the range.

Minor back–flow occurred through the upper section

of booths 22 and 23, with air traveling back as far as

the double doors directly uprange of these booths

and then returning through the booth. Smoke tests

uprange of the booths showed that the back–flow

was mainly caused by the air flow distribution inside

the door plenum. The louvers on the diffuser in this

plenum directed air straight toward the floor. The air

that impinged on the floor jetted along the floor

through the perforated panel door toward the booths.

This jet of air created a vertical eddy behind booths

22 and 23, which caused the back–flow through the

booths. Also, cardboard targets had been stored in

the plenum behind the air wall. When these were

removed the back–flow lessened. The air

distribution problem in the door plenum was the

major cause of the back–flow through these booths.

Some of the area uprange of the firing line was used

for storage of a few large items, including two large

bins and a pallet of cardboard target backings.

In addition, the control console was located on a

desk that was equipped with a vanity panel, uprange

of booths 12 and 13. Other range equipment and

furniture were located in the area uprange of the

booths. Even though smoke tests did not show that

any of these items affected air flow through the

booths, correction of the current air flow distribution

problems may cause the obstructions to create new

problems. Moreover, proper practice dictates that

obstructions to the air flow uprange of the booths be

minimized.

Gunsmiths' Indoor Range

There was no back–flow when smoke was released

on top of the desk in this range. However, smoke

released at the floor level flowed back to the desk

from as much as ten feet downrange of the desk.

Back–flowing air rose at the downrange end of the

desk, but air moving across the top of the desk pulled

the back–flow air downrange. Separate smoke tests

with two people simulating firing positions at the

desk showed that back–flowing air could enter the

shooter's breathing zone. As in the students' range,

removal of obstructions to the air flow would reduce

or eliminate the back–flow.

Although the gunsmiths' range was found to be

under negative pressure, design drawings showed

that the supply and exhaust air flows were equal.

To ensure that airborne lead dust does not escape the

range, it should have a greater exhaust than supply
Page 14 Health Hazard Evaluation Report No. 91–0346

air flow, placing the range under negative pressure.

Exhaust Fan Room

The current exhaust fan room does not function as

effectively as a built–up plenum because control of

leaks is difficult. Some of these leaks can affect the

pressurization, and thus the related thermal and

ventilation control of the ranges. In addition,

opening the door of the exhaust fan room while the

fan is running is difficult and unsafe. Leaks in the

room also directly affect the volume of air exhausted

from the ranges and, in turn, control of the

contaminants in the range. Maintenance functions in

the room are hazardous because all of the interior

surfaces of the room were covered with lead dust.

This dust could be spread through the building by

inadvertent pressurization of the room, or by

personnel carrying the dust into the building on

clothing or shoes. Air is not filtered before being

exhausted from the room to the outside. 

Linen Room

The fact that lead was not detected on the area air

sample collected in the linen room, which is adjacent

to the indoor range and which is connected to the

exhaust fan room, indicates that the airborne lead

concentration in the linen room during the sampling

period was less than 1 :g/m3

. Although it is very

likely that lead is transported into the linen room on

the shoes and clothing of people exiting the exhaust

fan room, this is not likely to result in high airborne

lead concentrations. If the exhaust fan room were to

become positively pressurized with respect to the

linen room, the result would be that lead dust in the

exhaust fan room would enter the linen room. 

Dormitory Room Lead Dust

Sampling

Results of the carpet dust sampling collected in 14

dormitory rooms that were used by FBI students, and

in 14 rooms that were used by non-students are

presented in Table 12. The non-student rooms were

used by various visitors to the FBI Academy who

would not typically be using the firing ranges in the

course of their activities. The lead concentrations are

given in micrograms of lead per gram of carpet dust

(:g/g). The total sample concentrations ranged from

116 to 546 :g/g with a geometric mean of 214 for

the students' rooms, while the non–student rooms

ranged from 50 to 188 :g/g with a geometric mean

of 65. A two-tailed t-test was performed on the data

from these rooms; the students' rooms had

significantly higher lead levels than the non–student

dorm rooms (p < 0.0005).

DISCUSSION

Lead

BLL test results from 1989 to 1991 for range

technicians, gunsmiths, and instructors showed

consistent BLL elevations in comparison to the

entire US adult population (geometric mean of

3.0 :g/dl) from 1988 to 1991.11 These results are

consistent with low-level occupational exposure to

lead. Exposures are probably due to a combination

of skin contamination (not measured) with

subsequent ingestion, chronic low-level airborne

exposure, and occasional short-term high airborne

lead exposure. Although none of the workers’ BLLs

exceeded the OSHA lead standard and were

generally below the U.S. Public Health Service goal

of 25 :g/dl10 (only two were above 25 :g/dl), there

are still potential adverse health effects that have

been associated with BLLs similar to those found in

FTU workers (i.e., small blood pressure elevations

associated with lead levels as low as 10 :g/dl7

). Of

note, BLLs for instructors indicated that their lead

exposures have been reduced over time, but those of

range technicians and gunsmiths, have not (Table 1).

Some of the instructors reported that the reduction in

their BLLs was due to increased awareness of lead

hazards and subsequent modification of work

practices to reduce lead exposures. No specific

information was available to substantiate these

reports. 

Custodians were found to have high short-term

airborne exposures to lead during sweeping and
Health Hazard Evaluation Report No. 91–0346 Page 15

vacuuming of an indoor firing range. However, they

all had low 1991 BLLs (below 4 :g/dl). The

custodians’ low BLLs are probably primarily due to

the fact that high exposure tasks were only

performed infrequently, for short time periods.

NIOSH and the National Center for Environmental

Health (NCEH), in a separate evaluation, found that

vehicles of FTU workers and student dormitory

rooms had elevated environmental lead levels, as

compared with controls. These findings indicate the

potential for take-home of workplace lead

exposures. Lead contamination of workers’ homes

can lead to additional lead exposures outside of the

workplace, for both workers and their families, and

underscores the need for good hygiene practices (i.e.,

hand washing, changing clothes, showering) to

reduce this potential exposure. 

Noise

Sixty–four percent (9 of 14) of the current instructors

and one range technician had audiometric changes

relative to baseline of 10 dB or more in the average

hearing level at 2000, 3000, and 4000 Hz (an OSHAdefined STS). Generally, in normal hearing, the

sound sensitivity or threshold should be below 25 dB

at 1000, 2000, and 3000 Hz. The normal pattern

seen on audiograms in cases of NIHL is a reduction

in sensitivity from about 2000 to 4000 Hz, with

recovery between 4000 to 8000 Hz. Gunfire NIHL

losses are most significant at 4000 Hz, which was

consistent with the findings seen on audiograms of

FTU workers. However, it is not possible to

determine whether the abnormalities found in FTU

workers were entirely due to NIHL, because high

frequency data (above 4000 Hz) were missing on

many of the tests.

In a previous study conducted by NIOSH researchers

on U.S. Secret Service Agents;23 researchers found

that shooters who wore ear muffs and improperly

inserted ear plugs experienced small positive

temporary threshold shifts (TTS) at 6000 Hz when

compared to shooters who wore ear muffs and

properly inserted ear plugs. As a result of these

findings, the NIOSH investigators concluded that

when both the earmuffs and properly inserted

earplugs are worn together, shooters receive

adequate protection from gunfire noise so that it

should not pose a considerable risk to hearing,

provided that the shooter has no other substantial

noise burden during the same 24-hour period. The

FBI FTU workers typically wear only ear muffs

during shooting sessions. The use of ear muffs only,

while not studied during the secret service

evaluation, most likely affords even less hearing

protection than ear muffs and improperly inserted ear

plugs. Therefore, FTU workers, and others exposed

to gunfire, who wear only ear muffs may be at

increased risk for NIHL. 

Another issue of potential concern are findings that

lead may be toxic to auditory centers of the brain.24

In one study of 3,545 subjects aged 6–19 years,

BLLs of even less than 10 :g/dl were found to be

associated with an increased risk of hearing

impairment.25 While little is presently known about

the combined effects of lead and noise on hearing, it

would be prudent to provide maximal hearing

protection to all workers with noise and lead

exposures.

Instructors

Outdoor Ranges

PBZ airborne lead concentrations for the firing range

instructors at the outdoor firing ranges were shown

to be highly variable (range: <3.0 :g/m3

 to

51.7 :g/m3

). The highest air concentrations were

measured during a training session at

Field 2 (Table 3). During this session, the trainees

fired 1024 rounds with 12–gauge shotguns and

5760 rounds using 9–millimeter handguns. During

a different session at Field 2 (Table 1), the trainees

fired nearly the same number of rounds, using

identical weapons and ammunition, but the

exposures were lower. The wind direction was

predominantly downrange during the course of the

latter training session. During the first session (Table

2), which was on a different day, the variable wind
Page 16 Health Hazard Evaluation Report No. 91–0346

direction seemed to be less effective at removing

airborne lead from the breathing zones of people near

the firing line. Results from other sessions show

similar variability in PBZ lead concentrations. Wind

direction and speed affect the degree to which

shooters and instructors are exposed to airborne lead

at the firing line.

The airborne concentration of lead measured from

one of the FBI instructors (sample 105, Table 2) was

51.7 :g/m3

 for a 174 minute sample, which would

result in an 8-hour TWA of 18.8 :g/m3

. This is

below the OSHA PEL of 50 :g/m3

 (8–hour TWA)

and the action level of 30 :g/m3

. However, this

concentration and the other relatively high lead

concentrations presented in Tables 2 and 5

demonstrate that the potential exists for firing range

instructors to have short-term exposures >50 :g/m3

.

Indoor Ranges

Air samples collected in the students' range

demonstrate that the ventilation effectively carried

airborne contaminants downrange, away from the

shooters and instructors. Airborne lead

concentrations in the exhaust fan room and just

outside the exhaust vent increased dramatically

during the second sampling period. This was due to

the increased amount of airborne lead fume and

particulate that was generated during the shooting

session. Samples 44, 45, 51, and 52 were collected

in the range behind the firing line at various points

indicated in Table 6 and shown on Figure 1. The

fact that lead was not detected on any of these

samples indicates that the air flow pattern in

the range was effective in moving airborne

contaminants downrange. The minimum detectable

concentration for an 80–minute sample period,

similar to the duration of the sampling period for the

samples collected behind the firing line, would be

about 5 :g/m3

. This means that airborne

concentrations in the sample locations behind the

firing line during the shooting session were less than

5 :g/m3

. 

Range Technicians

PBZ air sample results showed that the

Range Technicians were exposed to very low

levels of airborne lead during the two

days of sampling (range: <2.1 :g/m3

 to

2.7 :g/m3

). The Range Technicians do not often

work near the firing line during a shooting session,

or elsewhere where high airborne lead concentrations

would be expected. Since these workers are

responsible for maintaining and repairing the ranges,

and for supplying all of the ammunition, it is likely

that their main source of lead exposure would be

through skin contact and subsequent ingestion. Hand

wipes were not collected from these workers.

Gunsmiths

The variability of PBZ air sample results from the

gunsmiths (range: <1.1 :g/m3

 to 4.5 :g/m3) occurred

because not all of the gunsmiths fired weapons

during the sampling period. All four gunsmiths with

detectable personal lead exposures test–fired a

weapon in the gunsmiths' range during the sampling

period. The area samples, collected at the firing table

in the gunsmiths' range reflect airborne lead

concentrations very similar to those in the PBZ

samples for the gunsmiths who fired weapons. The

primary source of airborne lead exposure for the

gunsmiths is the test–firing of weapons. Although

hand wipes to identify dermal lead exposure were

not collected from these workers, a portion of their

total lead exposure probably arises from skin contact

with lead while repairing weapons.

Custodians

Results of PBZ air samples collected from the

Custodians who clean the students' range indicate

that they can be exposed to high short-term

concentrations of airborne lead (range: <10.0 :g/m3

to 220 :g/m3) during sweeping and vacuuming

downrange of the firing line. Assuming that

Custodian B encountered no other airborne lead

exposure for the rest of the day, that worker's 8–hour

TWA for the day would be 22.9 :g/m3

. This is
Health Hazard Evaluation Report No. 91–0346 Page 17

below the OSHA action level of 30 :g/m3, but it is

still a source of lead exposure. Custodians A and B

wore TyvekTM clothing and half–mask respirators

with HEPA filters while they cleaned the range.

However, these respirators did not appear to fit them

properly.

RECOMMENDATIONS

The following recommendations are made to assist

the FBI in reducing employee exposures to lead, to

improve medical surveillance of lead-exposed

workers, and to reduce the potential for NIHL: 

1. Food, beverages, tobacco products, and

cosmetics should not be used, carried into, or stored

in the firing ranges or in adjacent areas where lead

exposures may occur. All personnel exposed to lead

in the firing ranges should wash their hands and

faces before eating, drinking, smoking, or having

hand contact with other people. Washing should

occur after shooting, handling fired cartridge cases,

and cleaning weapons. These practices will reduce

the potential for lead exposure by ingestion.

2. After shooting or maintenance work in the

firing range, individuals should shower and change

clothes. Employees should be provided with both

"clean" and "dirty" storage lockers to allow them to

separate street clothes from lead-contaminated work

clothes.

3. Shooters using a kneeling or prone position

over lead contaminated surfaces should place a sheet

of heavy paper on the ground beneath them. The

paper should be large enough to cover any area

contacted by the shooter. This would reduce the

amount of settled lead containing dust that is

transferred to the shooter's clothing. Additionally,

shooting time in the kneeling and especially the

prone position should be limited. 

4. Non–lead or copper–jacketed bullets should

be used whenever possible because they have been

shown to reduce lead emissions. Substituting

copper–jacketed, nylon–jacketed, or zinc slugs has

been shown to result in significant reduction in lead

emission compared with traditional lead

ammunition.26 There will still be, however, some

lead generated from the primer, which contains lead

styphnate and lead peroxide. Ideally, non–lead

bullets using non–lead primers should be used.

5. The firing range ventilation system should

be in operation at all times while the range is in use

and during clean–up.

6. After each use, the floor of the indoor

firing range should be thoroughly cleaned with a

HEPA vacuum designed to collect lead dust.

Dry sweeping should never be used in the range.

The vacuum should have a plastic bag liner, and a

non–evaporating liquid, such as a light oil, should be

placed inside the vacuum to wet the powder to

prevent combustion.

7. Skin contact with spent cartridges should

be avoided whenever possible to reduce the

likelihood of the hand–to–mouth source of lead

exposure. Cartridges should be collected together

using a floor squeegee and picked up using a dust

pan or the HEPA vacuum. All clean–up should be

performed with the ventilation system running.

8. Surfaces inside the indoor range should be

cleaned routinely with a high-phosphate detergent,

such as trisodium phosphate (TSP), to reduce surface

lead contamination.

9. Personnel performing clean–up of lead at

the trap should wear appropriate respiratory

protection (for example, half–face respirators

equipped with HEPA filters) and full protective outer

clothing (which may be disposable). Personnel

performing the clean–up should be included in a

respiratory protection program as defined by OSHA

in 29 CFR 1910.134. Smoking or eating should be

prohibited during clean–up. After clean–up, workers

should remove their outer clothing inside the range

area to prevent spreading lead to other parts of the

building. Non–disposable protective clothing should

be laundered by the employer, not taken home.
Page 18 Health Hazard Evaluation Report No. 91–0346

10. Loose lead in the trap, including spent

bullets and lead chiseled from the trap, should be

collected with the HEPA vacuum to avoid skin

contact with lead. Disposable gloves should be worn

to remove larger pieces that cannot be removed with

the HEPA vacuum. Care should be taken to prevent

over–filling the vacuum to the point that it is difficult

to move or empty.

11. Only authorized personnel (range officer

and maintenance personnel) should be permitted to

go downrange of the firing line. Personnel going

downrange should wear protective clothing

(disposable or laundered by employer) to cover

portions of the body which will be in contact with

lead–covered surfaces. Adequate time should be

allowed for airborne lead fume and dust in the range

to be removed by the ventilation system before

personnel are allowed downrange.

12. At the indoor ranges, barricade shooting

should only be performed from the shooting booth.

To help prevent personnel from going downrange

malfunctioning target equipment should be promptly

repaired or not used. 

13. Carpeting should not be used anywhere

inside the range because it becomes a lead dust

"reservoir." Unspent primer could also accumulate

in the carpeting, creating a potential fire hazard.

The carpeting in the indoor ranges should be

removed.

14. To maximize efficiency of the ventilation

system, back–flow and air distribution problems in

the students' range should be corrected as follows:

g Missing turning vanes in the air wall

plenum should be replaced. In addition,

debris stuck in the vanes should be

removed, and the source of the debris

should be eliminated.

g Materials stored in the air wall plenum

should be removed and stored elsewhere. A

policy should be instituted forbidding the

area to be used for storage. A sign stating

that the area is not to be used for storage

should be posted on the door to the plenum.

g Obstructions to the air flow

from the air wall should be minimized.

Fixtures and equipment which are not needed

constantly, and materials stored inside the

range, should be removed and stored

elsewhere. Vertical surface areas should be

minimized. For example, the desk upon

which the control console currently sits should

be replaced with a table.

g Obstructions uprange of the

booths should be moved as close to the air

wall as possible.

15. The desk in the gunsmiths' range should be

replaced with a table to eliminate back–flow. In

addition, the current tool cabinets next to the desk

should be replaced with cabinets on the uprange end

of the wall. The new cabinets should be positioned

so that they do not interfere with the supply air flow.

16. All leaks from the gunsmiths' range into the

students' range should be tightly sealed. Expanding

foam insulation can be used to seal the leaks.

17. The plenum that contains the supply air filters

and heating coils for the ventilation system should be

extended to include the supply fan. This plenum

should be made as airtight as possible. In addition,

the feasibility of adding cooling coils to cool the

supply air should be investigated.

18. The exhaust system should be renovated as

follows:

g A new exhaust air/filter

plenum should be installed outside of the

building next to the current exhaust fan room.

A new plenum is necessary because the

current exhaust fan room is too small to

accommodate a new plenum with a filtration

system. This plenum should be air tight and

equipped with pre–filter and HEPA filter

systems. These filter systems should be
Health Hazard Evaluation Report No. 91–0346 Page 19

located upstream of the fan. The capacity of

the current exhaust fan should be analyzed to

verify that the fan can adequately control

both ranges. If the fan is inadequate, it

should be replaced.

g The current exhaust fan room and

contents should be decontaminated prior to

removal of the exhaust fan.

g To prevent settling of lead dust in the

ducts the current exhaust ducts should be

replaced with ducts sized for a velocity of

3500 feet per minute.27 Decontamination of

the old ducts may be needed before removal.

Ducts from the ranges should be connected

directly to the plenum.

g Protection for the exhaust ducts in the

ranges should be improved to prevent

additional bullet holes. Holes currently in the

ducts should be patched.

g The exhaust flow specified in the

design for the gunsmiths' range should be

changed so that the range is under negative

pressure.

19. While the previously discussed

recommendations have been aimed at preventing or

minimizing lead exposure, medical monitoring plays

an important role to ensure that individual workers

have been protected. The OSHA lead standard (29

CFR 1910.1025)20 requires biological monitoring of

lead exposed workers every six months for those

exposed above the TWA action level of 30 :g/m3

 for

more than 30 days per year. In one study, the BLLs

of law enforcement trainees using firing ranges for

an average of 7.2 hours during their first month of

training rose from a mean of 6 :g/dl to 51 :g/dl.28

Under these conditions, assuming a linear

relationship between hours of exposure and BLL,

employees using or working at the firing range more

than 3.6 hours per month could be at risk for BLLs

rising above 40 :g/dl. Assuming the same

environmental conditions, these findings suggest that

individuals using or working at the range for more

than 3 hours per month, should have their BLL

monitored. We recommend that FBI instructors,

gunsmiths, and range technicians should continue to

have their BLLs checked at least annually.

Monitoring frequency should be modified on an

individual basis depending on worker exposures,

previous BLL test results, and any other medical

concerns (e.g., pregnancy). FBI trainees should have

a baseline BLL at the beginning of training and

should then be monitored periodically with

frequency dependent upon exposures and BLL

results. 

20. All employees should be strongly encouraged

to use both ear muffs and ear plugs when working on

or near the firing ranges. A training program in the

use of ear plugs should be implemented by the

training staff at the firing ranges. Proper insertion

techniques can be easily shown to workers before

allowing them to enter the range.

21. All workers with regular exposure to weapons

firing should undergo annual audiometric

monitoring. All audiometric testing should include

the test frequencies of 500, 1000, 2000, 3000, 4000,

6000, and 8000 Hz. 

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Hygienists, pp 3–18.

28. Valway S, et al. [1989]. Lead absorption in

indoor firing range users. American Jour of Pub

Health 79:8:1029–1032.
Page 22 Health Hazard Evaluation Report No. 91–0346

Table 1

Blood Lead Testing Results, 1989–1991

FBI Academy, Quantico, VA

HETA 91-0346

Group Year No. Workers with

BLLs Done

Mean BLL (:g/dl)

(range)

Instructors 1989 7 14.6 (5–21)

 (16) 1990 7 13.7 (6–27)

1991 14 7.6 (<4–12)

Gunsmiths 1989 5 12.2 (8–15)

(13) 1990 5 11.0 (5–18)

1991 11 12.1 (<4–24)

Range Techs 1989 5 16.2 (10–24)

(6) 1990 5 10.4 (6–14)

1991 5 13.6 (8–28)

Custodians 1989 0 –

(6) 1990 0 –

1991 6 <4.0

BLL = blood lead level

:g/dl = micrograms per deciliter
Health Hazard Evaluation Report No. 91–0346 Page 23

Table 2

PBZ and Area Airborne Exposure Concentrations for Lead

Outdoor Range: Field 2

FBI Academy, Quantico, Virginia

December 11, 1991

HETA 91–0346

Sample type/location

Time

(minutes)

Volume

(liters)

Pb Concentration

(:g/m3

)

PBZ - FBI Instructor A 206 412 n.d. 

PBZ - FBI Instructor B 191 382 n.d

PBZ - FBI Instructor C 197 394 5.1 

PBZ - FBI Instructor D 212 424 n.d 

PBZ - FBI Instructor E 260 520 n.d 

PBZ - FBI Instructor F 238 476 n.d 

area: inside shelter 165 495 n.d 

area: on light pole 164 492 n.d 

PBZ = personal breathing zone

Pb = lead

:g = micrograms

:g/m3 = micrograms per cubic meter

n.d. = none detected

Rounds fired: 1024 (12-gauge shotguns)

3200 (9-mm handguns)

Minimum detectable concentration for a 400-liter sample = 2.5 :g/m3

Minimum quantifiable concentration for a 400-liter sample = 8.3 :g/m3
Page 24 Health Hazard Evaluation Report No. 91–0346

Table 3

PBZ and Area Airborne Exposure Concentrations for Lead

Outdoor Range: Field 2

FBI Academy, Quantico, VA

December 12, 1991

HETA 91–0346

Sample type/location

Time

(minutes)

Volume

(liters)

Pb Concentration

(:g/m3

)

PBZ - FBI Instructor E 171 342 38.0 

PBZ - FBI Instructor A 174 348 51.7 

PBZ - FBI Instructor C 132 264 15.2 

PBZ - FBI Instructor D 170 340 n.d. 

PBZ - FBI Instructor F 165 330 15.2 

PBZ - FBI Instructor B 165 330 45.5 

PBZ - FBI Instructor G 161 322 18.6 

area: on light pole 168 420 2.4 

PBZ = personal breathing zone

Pb = lead

:g = micrograms

:g/m3 = micrograms per cubic meter

n.d. = none detected

Rounds fired: 1024 (12-gauge shotguns)

5760 (9-mm handguns)

Minimum detectable concentration for a 330-liter sample = 3.0 :g/m3

Minimum quantifiable concentration for a 330-liter sample = 10 :g/m3
Health Hazard Evaluation Report No. 91–0346 Page 25

Table 4

PBZ and Area Airborne Exposure Concentrations for Lead

Outdoor Range: Field 1

FBI Academy, Quantico, VA

December 12, 1991

HETA 91–0346

Sample type/location

Time

(minutes)

Volume

(liters)

Pb Concentration

(:g/m3

)

PBZ - FBI Instructor H 184 359 8.4 

PBZ - FBI Instructor I 200 400 10.0 

PBZ - FBI Instructor J 195 390 5.1 

PBZ - FBI Instructor K 188 357 5.6 

PBZ - FBI Instructor L 195 390 5.1 

PBZ - FBI Instructor M 249 498 n.d. 

area: on light pole 201 492 2.0 

PBZ = personal breathing zone

Pb = lead

:g = micrograms

:g/m3 = micrograms per cubic meter

n.d. = none detected

Weapons fired: 9-mm handguns

Minimum detectable concentration for a 400-liter sample = 2.5 :g/m3

Minimum quantifiable concentration for a 400-liter sample = 8.3 :g/m3
Page 26 Health Hazard Evaluation Report No. 91–0346

Table 5

PBZ and Area Airborne Exposure Concentrations for Lead

Outdoor Range: Field 3

FBI Academy, Quantico, VA

December 12, 1991

HETA 91–0346

Sample type/location

Time

(minutes)

Volume

(liters)

Pb Concentration

(:g/m3

)

PBZ - DEA Instructor A 167 334 6.0 

PBZ - DEA Instructor B 109 218 9.2 

PBZ - DEA Instructor C 115 230 17.4 

PBZ - DEA Instructor D 113 226 13.3 

area: on light pole 176 440 n.d. 

PBZ = personal breathing zone

Pb = lead

:g = micrograms

:g/m3 = micrograms per cubic meter

n.d. = none detected

Rounds fired: 2200 (9-mm handguns)

Minimum detectable concentration for a 230-liter sample = 4.3 :g/m3

Minimum quantifiable concentration for a 230-liter sample = 14.3 :g/m3
Health Hazard Evaluation Report No. 91–0346 Page 27

Table 6

PBZ and Area Airborne Exposure Concentrations for Lead

Outdoor Ranges: Electric Range and Stress Obstacle Course

FBI Academy, Quantico, VA

December 11, 1991

HETA 91–346

Sample type/location

Time

(minutes)

Volume

(liters)

Pb Concentration

(:g/m3

)

Samples collected at electric range

PBZ - FBI Instructor N 263 526 n.d. 

PBZ - FBI Instructor I 206 412 4.9 

area: behind firing line 249 747 n.d.

Samples collected at stress obstacle course

PBZ - FBI Instructor O 235 470 29.8 

PBZ - FBI Instructor L 232 464 30.2 

area: at start of course 243 608 n.d. 

PBZ = personal breathing zone

Pb = lead

:g = micrograms

:g/m3 = micrograms per cubic meter

n.d. = none detected

Minimum detectable concentration for a 470-liter sample = 2.1 :g/m3

Minimum quantifiable concentration for a 470-liter sample = 7.0 :g/m3
Page 28 Health Hazard Evaluation Report No. 91–0346

Table 7

Airborne Exposure Concentrations for Lead

Students' Indoor Range

FBI Academy, Quantico, VA

December 11, 1991

HETA 91–0346

Sample location

Time

(minutes)

Volume

(liters)

Pb Concentration

(:g/m3)

No weapon firing during sampling period

outside air intake 160 400 n.d.

just inside intake 145 326 n.d.

intake plenum 145 363 n.d.

behind pegboard 152 456 n.d.

control table 136 340 n.d.

station #17 138 345 n.d.

down-range pillar 137 411 n.d.

exhaust fan room 143 358 2.8

outside exhaust 157 353 22.7

Samples collected during shooting session

outside air intake 94 212 n.d.

just inside intake 100 225 n.d.

intake plenum 98 239 n.d.

behind pegboard 106 318 n.d.

control table 84 189 n.d.

just behind #14 62 186 n.d.

station #14 60 150 n.d.

station #17 87 196 n.d.

down-range pillar 85 255 145.1

exhaust fan room 92 207 338.2

outside exhaust 93 209 186.6

PBZ = personal breathing zone Pb = lead

:g = micrograms :g/m3 = micrograms per cubic meter

n.d. = none detected

Minimum detectable concentration for a 250-liter sample = 4.0 :g/m3

Minimum quantifiable concentration for a 250-liter sample = 13.2 :g/m3

Minimum detectable concentration for a 400-liter sample = 2.5 :g/m3

Minimum quantifiable concentration for a 400-liter sample = 8.3 :g/m3
Health Hazard Evaluation Report No. 91–0346 Page 29

Table 8

PBZ Airborne Concentrations for Lead

Range Technicians

FBI Academy, Quantico, VA

December 11 & 12, 1991

HETA 91–0346

Sample type/location

Time

(minutes)

Volume

(liters)

Pb Concentration

(:g/m3

)

December 11, 1991

PBZ - Range Technician A 384 768 n.d. 

PBZ - Range Technician B 153 306 n.d.

PBZ - Range Technician C 380 760 2.6 

PBZ - Range Technician D 376 752 2.7 

PBZ - Range Technician E 458 916 2.2 

PBZ - Range Technician F 395 790 n.d. 

December 12, 1991

PBZ - Range Technician D 231 462 n.d.

PBZ - Range Technician A 235 470 n.d.

PBZ - Range Technician E 231 462 n.d.

PBZ - Range Technician F 238 476 n.d.

PBZ - Range Technician C 237 474 n.d.

PBZ - Range Technician B 242 484 n.d.

PBZ = personal breathing zone Pb = lead

:g = micrograms n.d. = none detected

:g/m3 = micrograms per cubic meter

Minimum detectable concentration for a 750-liter sample = 1.3 :g/m3

Minimum quantifiable concentration for a 750-liter sample = 4.4 :g/m3

Minimum detectable concentration for a 400-liter sample = 2.1 :g/m3

Minimum quantifiable concentration for a 400-liter sample = 7.0 :g/m3
Page 30 Health Hazard Evaluation Report No. 91–0346

Table 9

PBZ and Area Airborne Exposure Concentrations for Lead

Gunsmiths

FBI Academy, Quantico, VA

December 11 & 12, 1991

HETA 91–0346

Sample type/location

Time

(minutes)

Volume

(liters)

Pb Concentration

(:g/m3)

December 11, 1991

PBZ - Gunsmith A 538 1022 2.0 

PBZ - Gunsmith B 429 837 n.d. 

PBZ - Gunsmith C 444 888 4.5 

PBZ - Gunsmith D 495 990 n.d.

PBZ - Gunsmith E 411 801 0.0 

PBZ - Gunsmith F 523 1046 3.8 

PBZ - Gunsmith G 408 796 n.d.

PBZ - Gunsmith H 445 890 n.d.

PBZ - Gunsmith I 439 878 n.d.

area - firing table 502 1506 4.6

December 12, 1991

PBZ - Gunsmith A 504 1008 n.d.

PBZ - Gunsmith E 467 934 1.1 

PBZ - Gunsmith H 460 920 n.d.

PBZ - Gunsmith C 506 1012 n.d.

PBZ - Gunsmith J 311 606 n.d.

PBZ - Gunsmith B 396 792 n.d.

PBZ - Gunsmith I 421 842 n.d.

PBZ - Gunsmith G 492 984 n.d.

PBZ - Gunsmith F 242 484 n.d.

area - firing table 512 1024 1.0 

PBZ = personal breathing zone Pb = lead

:g = micrograms :g/m3 = micrograms per cubic meter

n.d. = none detected

Minimum detectable concentration for a 900-liter sample = 1.1 :g/m3

Minimum quantifiable concentration for a 900-liter sample = 3.7 :g/m3
Health Hazard Evaluation Report No. 91–0346 Page 31

Table 10

PBZ and Area Airborne Exposure Concentrations for Lead

Indoor Range and Linen Room

FBI Academy, Quantico, VA

December 12, 1991

HETA 91–0346

Sample type/location Time

(minutes)

Volume

(liters)

Pb

Concentration

(:g/m3

)

PBZ - HRT agent

shooting in indoor range

86 172 n.d. 

area: linen room adjacent to indoor range 524 1048 n.d.

PBZ = personal breathing zone Pb = lead

:g = micrograms :g/m3 = micrograms per cubic meter

n.d. = none detected

Sample collected in indoor range

Rounds fired: 182 (9-mm handgun)

Minimum detectable concentration for a 1048-liter sample = 1.0 :g/m3

Minimum quantifiable concentration for a 1048-liter sample = 3.1 :g/m3

Table 11

PBZ Airborne Exposure Concentrations for Lead

Indoor Range Custodians

FBI Academy, Quantico, VA

December 12, 1991

HETA 91–0346

Sample type/location

Time

(minutes)

Volume

(liters)

Pb Concentration

(:g/m3)

PBZ - Custodian A* 51 102 127.5 

PBZ - Custodian B* 50 100 220.0 

PBZ - Custodian C** 42 84 n.d. 

Samples were collected while workers cleaned the indoor range.

*These workers cleaned the cement floor of the range.

**This worker vacuumed the carpet behind the firing line.

PBZ = personal breathing zone Pb = lead

:g = micrograms :g/m3 = micrograms per cubic meter

n.d. = none detected

Minimum detectable concentration for a 100-liter sample = 10 :g/m3

Minimum quantifiable concentration for a 100-liter sample = 33 :g/m3
Page 32 Health Hazard Evaluation Report No. 91–0346

Table 12

FBI Academy, Quantico, VA

December 11 & 12, 1991

HETA 91–0346

Sample

number

Total Sample

Concentration

(:g/g)

ln Total

Sample

Concentration

(:g/g)

Sample

number

Total Sample

Concentration

(:g/g)

ln Total Sample

Concentration

(:g/g)

101 169 5.13 201 52 3.94

102 174 5.16 202 188 5.24

103 141 4.95 203 51 3.94

104 393 5.97 204 117 4.76

105 168 5.12 205 53 3.96

106 116 4.75 206 66 4.19

107 352 5.86 207 71 4.26

108 356 5.88 208 51 3.93

109 207 5.33 209 48 3.87

110 546 6.30 210 47 3.84

111 227 5.42 211 58 4.06

112 161 5.08 212 75 4.31

113 179 5.19 213 72 4.28

114 143 4.96 214 50 3.91

geometric

mean

214 geometric

mean

65

geometric

standard

deviation

1.58 geometric

standard

deviation

1.48