HETA 96–0019–2666

Los Angeles County Department of Coroner

Los Angeles, California

Kenneth F. Martinez, M.S.E.E., C.I.H.

Randy L. Tubbs, Ph.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, technical and

consultative assistance 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 Kenneth F. Martinez and Randy L. Tubbs, of the Hazard Evaluations and

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

Field assistance was provided by John Decker. Desktop publishing was performed by Ellen Blythe and

Nichole Herbert.

Copies of this report have been sent to employee and management representatives at LACDC 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 96–0019–2666

Los Angeles County Department of Coroner

Los Angeles, California

December 1997

Kenneth F. Martinez, M.S.E.E., C.I.H.

Randy L. Tubbs, Ph.D.

SUMMARY

On October 25, 1995, the National Institute for Occupational Safety and Health (NIOSH) received a request to

conduct a health hazard evaluation (HHE) from the office of the Los Angeles County Department of Coroner.

Specifically, the request was for NIOSH assistance in evaluating a pneumatic reciprocating saw equipped with local

exhaust ventilation (LEV) used for cranial openings during forensic autopsies and examinations. The pneumatic

saw was being evaluated by the coroner’s office as an alternative to an electrically-driven reciprocating saw. The

objective of the NIOSH evaluation was to determine if the alternative reciprocating saw (1) generates less tissue

and bone fragment aerosol that could potentially challenge the breathing zone of the operating forensic technician,

and (2) reduces the noise exposure to the technician and surrounding personnel.

A site visit was conducted by NIOSH investigators (including two industrial hygienists and a psychoacoustician)

on December 13–14, 1995. The investigation was conducted in coordination with the Los Angeles County Health

Department who simultaneously collected particulate air samples for microscopic analysis of bone and tissue

fragments. The NIOSH investigation included real–time area and personal measurements of airborne particulates

and spectral measurements of noise during the conduct of six autopsies (four autopsies for the noise evaluation).

Differences in peak concentrations of airborne particulates measured during autopsies, with and without the aide

of local exhaust ventilation (LEV), indicate that LEV significantly reduces the aerosols produced by the

reciprocating saws. No short-term, high concentrations of particulates were observed during autopsies utilizing

the LEV system. Aerosol concentrations measured during the use of both saws, without LEV, were one to two

orders of magnitude over baseline, and personal real–time air samples indicate that these aerosols were present in

the breathing zone of the operating technician.

The noise measurements from the two types of reciprocating saws suggest that the noise levels do not exceed noise

occupational exposure limits. Although levels approached 95 dB(A), during a 15–second period, the short amount

of time which the physician or technician are subjected to the noise lowers the time–weighted average (TWA)

exposure below all evaluation criteria. Even the most conservative exposure criteria of NIOSH and the American

Conference of Governmental Industrial Hygienists (ACGIH®) allow exposure to 95 dB(A) for a total time of

slightly less than one hour. The noise exposures last two minutes or less for each autopsy. It is unlikely that

employees would perform 30 autopsies per day.

LEV applied at the cutting surface of reciprocating surgical saws can be an effective tool to reduce the risk

of occupational exposure to blood, bone, and tissue aerosol fragments during autopsies which may be

contaminated by infectious agents (e.g., Mycobacterium tuberculosis). However, the vacuum recovery

system should be mechanically integrated with the activation of the reciprocating saw, eliminating the

possibility of operator error. Noise levels generated by these surgical devices should not exceed the

evaluation criteria for hazardous noise exposure given the short duration of their use.

Keywords: SIC 9221 (Police Protection) tuberculosis, HIV, coroner, bloodborne pathogen, noise, cranial saws
TABLE OF CONTENTS

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

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

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

Introduction ......................................................................... 2

Background ......................................................................... 2

Methods ........................................................................... 3

Particulates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

Noise . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

Evaluation Criteria . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

Noise . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

Particulates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

Noise . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

Discussion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

Particulates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

Noise . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Page 2 Health Hazard Evaluation Report No. 96–0019

INTRODUCTION

On October 25, 1995, the National Institute for

Occupational Safety and Health (NIOSH) received a

request to conduct a health hazard evaluation (HHE)

from the office of the Los Angeles County

Department of Coroner (LACDOC). Specifically,

the request was for NIOSH assistance in evaluating

a pneumatic reciprocating saw equipped with local

exhaust ventilation (LEV) used for cranial openings

during forensic autopsies and examinations. The

pneumatic saw was being evaluated by the coroner’s

office as an alternative to the electrically-driven

reciprocating saw. The objective of the NIOSH

evaluation was to determine if the reciprocating saw

(1) generates less tissue and bone fragment aerosol

that could potentially challenge the breathing zone of

the operating forensic technician, and (2) reduces the

noise exposure to the technician and surrounding

personnel.

A site visit was conducted by NIOSH investigators

(including two industrial hygienists and a

psychoacoustician) on December 13–14, 1995. The

investigation was conducted in coordination with the

Los Angeles County Health Department who

simultaneously collected particulate air samples for

microscopic analysis of bone and tissue fragments.

The NIOSH investigation included real–time area

and personal measurement of airborne particulates

and real–time spectral measurement of noise during

the conduct of six autopsies (four autopsies for the

noise evaluation).

BACKGROUND

During the first six months of 1995, two active cases

of tuberculosis (TB) and 10 tuberculin skin test

(TST) conversions among employees were reported

by the LACDOC. Additionally, in December 1995,

one case of active disease was diagnosed in a general

relief worker operating as a janitor for the building.

An epidemiologic assessment concluded that a high

risk of TB infection was evident for LACDOC

employees.1

 Autopsy room workers were five times

more likely to develop TB infection than other

employees. Employee to employee transmission was

ruled out in the outbreak. However, the possible

transmission of disease from the cadaver to

employees could not be ruled out.

The LACDOC building is concrete and glass

construction and is approximately 27 years old. The

overall ventilation systems were reported to be

functioning at 75 percent of design capacity with

many of the components in need of maintenance and

repair.1

 Autopsies are primarily conducted in three

rooms; the main rooms have table capacities for five

and six simultaneous autopsies, while a smaller room

has a capacity for three. The smaller of the three

autopsy rooms was designated for cases suspected of

human immunodeficiency virus (HIV) or TB

infection. A test and balance of the ventilation

systems serving the autopsy rooms indicated that the

main autopsy room was under negative pressure

(having approximately 20 air changes per hour

[ACH]), whereas, the smaller autopsy room was

under positive pressure. As a result, a separate

exhaust system was installed in the small autopsy

room to place it under negative pressure relative to

the corridor, achieving a maximum air change rate of

approximately 24 ACH.

In addition to the changes made to the ventilation

system in the small autopsy room, in the first quarter

of 1996, LACDOC initiated a study evaluating the

implementation of a pneumatically driven

reciprocating saw (Salam International Model 1100,

Laguna Niguel, California) equipped with LEV to

reduce occupational exposures to blood and other

bodily fluids. If effective, the pneumatic saw would

replace an electrically-driven saw (Stryker Model

810) then currently being used. The pneumatic saw

operates at a speed of 19,000 cycles per minute

(cycles/min), whereas, the electric saw operates at a

speed of 17,000 cycles/min. The LEV on the

pneumatic model consists of a hood and spray nozzle

connected to an aqueous spray/vacuum extraction

system. The aqueous spray/vacuum extraction

system is physically located in adjacent space (i.e.,

the building garage) to the small autopsy room. The

holding tank on the vacuum extraction system
Health Hazard Evaluation Report No. 96–0019 Page 3

contains a 10 percent bleach solution to

decontaminate incoming materials. Additionally, the

exhaust on the vacuum extraction system is equipped

with an internal high efficiency particulate air

(HEPA) filter.

METHODS

Particulates

Real–time sampling for airborne particulates was

conducted with three light–scattering instruments;

the Grimm Model 1105 Dust Monitor (Labortechnik

GmbH & CoKG, Ainring, Germany); the Met–One

Model 227 Hand–Held Particle Counter (Met–One,

Inc., Grants Pass, Oregon); and the Handheld

Aerosol Monitor (HAM [PPM, Inc., Knoxville,

Tennessee]). The Grimm Dust Monitor is a light

scattering aerosol spectrometer designed for

real–time particulate measurement with particle size

discrimination. Eight channels collect count

information for particle sizes greater than 0.75, 1, 2,

3.5, 5, 7.5, 10, and 15 micrometers (:m). The

Met–One Particle Counter counts particles

simultaneously using a solid state laser diode in two

size ranges (0.3 and 1 :m were selected for this

survey) at an operating flow rate of 2.8 liters per

minute (lpm). The HAM uses near–forward

scattering of infrared light with an instrument

response designed to fit the respirable aerosol

fraction. Data were collected during six autopsies to

monitor the particulates generated by distinct events.

The monitors probe inlets were mounted

approximately 15 centimeters above the forehead of

the decedent. For each autopsy, data were integrated

for 1 second (sec) and stored sequentially on the

Grimm data card over the entire time period. The

collected particle count and size information was

downloaded to a laptop computer following the

completion of the autopsy. Start and stop times for

significant autopsy events were recorded during each

sample collection period.

Noise

Real–time area noise sampling was conducted with

a Larson–Davis Laboratory Model 2800 Real–Time

Analyzer equipped with Larson–Davis Laboratory

Model 2559 1⁄2" random incidence microphone. This

instrument allows for the analysis of noise into its

spectral components in a real–time mode. The

one–third octave center frequency bands from

8 Hertz (Hz) to 16 kilohertz ( kHz) were integrated

for 15 seconds and stored sequentially in the analyzer

over the time period necessary for the technician to

open the skull for inspection by the pathologist. An

attempt was made to only store samples which

contained a full 15–seconds of sawing. If the

technician turned off the saw before the sample was

complete, the analyzer was reset and that sample

discarded. The analyzer was mounted on a tripod

placed at the right side of the autopsy table next to

the cadaver’s head with the microphone at

approximately the level of the technician’s ear while

he was using the saw. Ambient noise levels in the

room, while the saw was not in use, were also stored

for each of the cadavers that were surveyed.

EVALUATION CRITERIA

The occupational hazards encountered by health care

professionals are varied. These hazards include

exposures to biologic, chemical, and physical agents,

as well as ergonomic challenges posed by the

manipulation and transport of patients. In 1988,

NIOSH published a document that focused on

protecting the safety and health of health care

workers. NIOSH found that, compared to the

civilian workforce, hospital workers have a greater

percentage of workers’ compensation claims for

sprains and strains, infectious and parasitic diseases,

dermatitis, hepatitis, mental disorders, eye diseases,

influenza, and toxic hepatitis.2

 Probably the most

occupationally unique and high risk hazards are

posed by exposures to infectious agents. In some

instances, the risk of occupationally acquired

infections is of such concern that comprehensive,

agent focused guidelines have been published by the

Centers for Disease Control and Prevention (CDC).
Page 4 Health Hazard Evaluation Report No. 96–0019

Specifically, these guidelines have addressed

occupational exposures to Mycobacterium

tuberculosis, human immunodeficiency virus (HIV),

and hepatitis B virus (HBV).3,4 In 1991, OSHA

published their final rule on occupational exposures

to bloodborne pathogens.5

 The bloodborne

pathogens rule is in part based on the concept of

"universal precautions." Universal precautions are

defined as the treatment of all human blood and

certain human body fluids as if known to be

infectious for human immunodeficiency virus (HIV),

hepatitis B virus (HBV), and other bloodborne

pathogens. In 1996, OSHA developed a directive for

enforcement procedures and scheduling for

occupational exposures to tuberculosis.6

Within the health care industry, certain sectors are

known to present greater exposure risk potentials to

both bloodborne pathogens and tubercle bacilli.

During the conduct of autopsies, an increased risk to

the pathologist and pathology technicians can result

from unknown disease etiologies and potentially

large infectious agent concentrations released during

invasive procedures. The infectious diseases of

special concern during autopsies (or more generally,

infection hazards in the deceased) have included

tuberculosis, hepatitis B and C virus, HIV,

Creutzfeldt–Jacob disease, group A streptococcal

infection, gastrointestinal organisms, and possibly

meningitis and septicaemia (especially

meningococcal).7,8 Recent concerns about the

increasing incidence of hantavirus pulmonary

syndrome (HPS) have resulted in questions regarding

the level of biosafety necessary to protect autopsy

prosectors operating on decedents known to have

been infected with hantavirus. Given the limited

biosafety information regarding HPS and the serious

consequences of infection, recommendations have

been made to use biosafety level (BSL) 2 facilities

and BSL 3 procedures and practices.9

 Tuberculosis

has gained increasing attention as a significant

exposure concern during the conduct of autopsies.

Sugita et al. demonstrated an increased odds ratio

(6.08–10.98) among pathologists and pathology

technicians engaged in their current specialist work

compared to control groups.10 Recent case studies of

outbreaks among autopsy personnel resulting from

occupational exposures have been documented.11,12,13

Specific ventilation criteria for autopsy rooms, in

which the decedent is suspected of having an

infectious disease at the time of death, currently do

not exist. However, the American Society for

Heating, Refrigerating, and Air–Conditioning

Engineers (ASHRAE) and the American Institute of

Architects (AIA) have published ventilation specific

guidelines for autopsy areas.14,15 These guidelines

recommend that autopsy areas be provided with at

least 12 ACH. Additionally, ASHRAE recommends

a minimum contribution of 2 outdoor ACHs; AIA

does not have a provision for the introduction of

outdoor air.

Noise

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.16 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, noise–induced hearing

loss is insidious. Typically, it begins to develop at

4000 or 6000 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.17

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

unit for measuring sound levels to assess worker
Health Hazard Evaluation Report No. 96–0019 Page 5

Dose C T C T C T = × + ++ 100 11 2 2 n n noise exposures. The dB(A) scale is weighted to ( / / ... / ),

approximate the sensory response of the human ear

to sound frequencies near the threshold of hearing.

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. Because the dB(A) scale is logarithmic,

increases of 3 dB(A), 10 dB(A), and 20 dB(A)

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) specifies a maximum PEL

of 90 dB(A) for a duration of eight hours per day.18

The regulation, in calculating the PEL, uses a 5 dB

time/intensity trading relationship, or exchange rate.

This means that a person may be exposed to noise

levels of 95 dB(A) for no more than 4 hours, to

100 dB(A) for 2 hours, etc. Conversely, up to

16 hours exposure to 85 dB(A) is allowed by this

exchange rate. NIOSH, in its Criteria for a

Recommended Standard, proposed a REL of

85 dB(A) for 8 hours, 5 dB less than the OSHA

standard.19 The NIOSH 1972 criteria document also

used a 5 dB time/intensity trading relationship in

calculating exposure limits. However, in 1995,

NIOSH changed its official recommendation for an

exchange rate of 5 dB to 3 dB.20 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 time–varying noise exposures.21 Thus, a

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

to no more than 88 dB(A) for 4 hours or 91 dB(A)

for 2 hours. 

The duration and sound level intensities can be

combined in order to calculate a worker's daily noise

dose according to the formula:

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 Table G–16a of the

OSHA noise regulation.18 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 OSHA PEL.

The OSHA regulation has an additional action level

(AL) of 85 dB(A); 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, audiometric testing, hearing protectors,

training, and recordkeeping. All of these

requirements are included in 29 CFR 1910.95,

paragraphs (c) through (o).

Finally, the OSHA noise standard 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. However, in

1983, a compliance memorandum (CPL 2–2.35)

directed OSHA compliance officers not to cite

employers for lack of engineering controls until

workers’ TWA levels exceed 100 dB(A), so long as

the company has an effective hearing conservation

program in place. Even in TWA levels in excess of

100 dB(A), compliance officers are to use their

discretion in issuing fines for lack of engineering

controls.

RESULTS

Particulates

Figures 1, 3, 5, 8, 10, and 13 present graphical

representations of the real–time data collected with

the Met–One particle counter for the six monitored

autopsies. Particle count measurements were made

over the complete time period of each autopsy.

Figures 8 and 10 depict data collected during the use

of the electric saw without LEV. Figures 1, 3, 5, and
Page 6 Health Hazard Evaluation Report No. 96–0019

13 depict data collected during the use of the

pneumatic saw with LEV. It is important to note that

the time period for the use of the cranial saw for each

monitored autopsy composed only a small portion of

the entire procedure; on the order of one to two

minutes. For all of the monitored autopsies, no

distinctly observable effect is apparent for

particles > 0.3 :m, but for particles > 1 :m, peaks

are observable in Figures 2, 8, and 10. These peaks

correspond to the use of the reciprocating saw on the

cranial region of the decedent and range from one to

two orders of magnitude above the baseline.

Additionally, the lack of observable peaks for

particles > 0.3 :m indicate that the diameters of

particles generated by the use of the reciprocating

saws predominate at > 1 :m. It is important to note

that during the second autopsy (Figure 3), the

exhaust flow for the LEV was inoperable (the

technician was not aware that the switch for the unit

was turned off) during the first half of the time

period that the pneumatic saw was used. The peak

observed in Figure 3 coincides with the inoperability

of the LEV.

Figures 6, 9, 11, and 14 present the HAM real–time

measurement results collected on the operating

technician during the complete time period of each

individual autopsy (due to instrument malfunction,

data were only available for autopsies 3 through 6).

Note that the results from the HAM are reported as

concentration estimates of particulate load (i.e.,

milligrams per cubic meter of air) and cannot be

quantitatively compared to the other aerosol

measurements reported in total counts per volume of

sampled air (i.e., particles per liter). However,

observation of qualitative trends can be used to

understand exposure points during each autopsy.

Specifically, the peaks observed in the HAM

graphical representations (i.e., Figures 9 and 11)

correlate, in time, with the peaks observed in the

Met–One data created by the use of the reciprocating

saw.

Figures 2, 4, 7, 12, and 15 present graphical

representations of the real–time data collected with

the Grimm particle counter for five of the six

monitored autopsies (due to instrument malfunction,

data was not collected for autopsy 5). As with the

other real–time measurements, attempts were made

to collect data over the complete time period of each

autopsy. Figure 12 depicts data collected during the

use of the electric saw without LEV. Figures 2, 4, 7,

and 15 depict data collected during the use of the

pneumatic saw with LEV. For all of the monitored

autopsies, minimal or reduced observable effects are

apparent for particles > 0.75 :m, but for all

remaining particle cut points, peaks are observable in

Figures 2, 4, 12, and 15. These peaks correspond to

the use of the reciprocating saw on the cranial region

of the decedent. The most significant increases in

relative concentrations occur for the cut points at 2,

2.5, and 3 :m. When the electric saw was applied,

observable effects are noted for all particle size cut

points (except for particles > 15 :m) ranging from

one–half to two orders of magnitude above the

baseline. As seen in the Met–One results, a peak is

observed (Figure 4) which coincides with the

inoperability of the LEV during the initial segment of

the cranial cut.

Noise

Noise from the saws used on four cadavers was

analyzed with three sets of samples with the

pneumatic saw and one set with the electric saw.

The cranial procedure took approximately 75 to

105 seconds to complete; therefore, five to seven

individual spectral plots of 15–seconds duration were

stored for analysis. Cases #1–3 had the technician

operating the pneumatic saw and case #7's cranium

was opened by two different electric saws because of

a failure of the first saw during the procedure.

Inspection of the individual spectral plots revealed a

general pattern of higher noise exposures associated

with the earlier cutting and lesser amounts of overall

noise on successive samples. Specifically, for

case #1, the noise levels went from 92.8 to

85.6 dB(A); case #2 levels ranged from 93.5 to

88.7 dB(A); case #3 levels were 94.8 to 88.6 dB(A);

and case #7 ranged from 94.9 to 86.5 dB(A).

A comparison of the one–third octave band noise

levels for the pneumatic and electric saws is

presented in Figure 17. The spectra that are shown
Health Hazard Evaluation Report No. 96–0019 Page 7

are average levels for the entire procedure of opening

the cranium. The pneumatic saw data is from the

five individual samples recorded on body #2 while

the electric saw data represents both saws used on

body #7 over the seven individual samples. The data

show little difference in the noise emitted by the two

types of saws. The peak energy level for the

pneumatic saw was recorded at the 4 kHz third

octave band while the maximum for the electric saw

was at 5 kHz. The electric saw also had greater

energy in the third octave bands higher than 5 kHz.

The average overall noise energy was slightly higher

for the electric saw on both the A–weighted scale

and unweighted (sound pressure level [SPL]) scale.

However, these differences of 1–2 dB are not

generally perceptible to normal hearing listeners.

The fluid delivery and HEPA vacuum recovery

system which supports the pneumatic saw were

located in the garage area adjacent to the autopsy

room. The garage area is accessible through a

doorway which was closed during autopsy.

LACDOC employees were seen in the opposite end

of the garage while the system was in use. A spectral

average of the noise coming from the system was

measured at a distance of approximately four feet

from the vacuum and at ear level of a standing

person. The data (Figure 18) show that much of the

noise energy is emitted at 500 to 4000 Hz, but that

the overall levels are not in excess of any relevant

criteria since the system is on only during the time

when the saw is operational. 

During the survey of the pneumatic saw, the

technician seemed to not be totally familiar with this

relatively new piece of equipment. The saw was

designed so that the fluid delivery system and the

vacuum recovery system could be operated

independent of the saw blade. That is, a deliberate

effort had to be made to turn on the vacuum and fluid

systems before pressing the trigger which would

activate the blade. During the first autopsy, all of the

saw’s systems were operating. However, during

subsequent autopsies, the fluid and vacuum systems

were inadvertently turned off on the initial cut into

the skull on the second autopsy and the fluid delivery

was off for the initial cut during the third autopsy.

The noise samples for each of these three events are

presented in Figure 19. The overall noise levels were

lowest when the complete cutting system was in

operation. The greatest effects of the fluid and

vacuum systems on the noise can be seen in the

higher frequency, third–octave bands at and above

4kHz.

DISCUSSION

Particulates

The real–time measurement data collected with the

Met–One and Grimm instruments (reported as

particles/liter [part/L]) were similar. The baseline

readings for both instruments during the sampled

autopsies (for particles > 1:m) were focused

between 1000 and 2000 part/L. For the Grimm, data

from autopsies 1 through 4 were collected as

integrated one minute samples; the sample

measurements for autopsies 5 and 6 were collected at

six second intervals. All of the Met–One

measurements were collected over 10 second

intervals. The longer sample period for the earlier

Grimm measurements may account for the lower

comparative particle concentrations; longer sample

periods result in a dampening of the peaks due to an

averaging of all values over the entire sample period.

Specifically, if the sample period includes numerous

data points that approach the particle concentration

baseline, the lower values will weight the average

toward the baseline.

For all of the monitored autopsies, no distinctly

observable effect is apparent for particles > 0.3 :m,

as measured by the Met–One. This is consistent with

the Grimm results which present smaller peak values

(relative to the baseline) at the 0.75 :m cut–point

compared to all other values at cut–points of 2, 2.5,

and 3 :m over the same sample period. These

reduced particle concentrations in the

sub–micrometer size range indicate that a significant

portion of the particles emitted by application of

reciprocating saws are above 1 :m. This is contrary

to previously published data which indicate median

diameters in the sub–micrometer size range. Green
Page 8 Health Hazard Evaluation Report No. 96–0019

and Yoshida (1990) measured (in the breathing zone

of a pathology technician) the aerosols generated by

the application of a reciprocating saw during five

cranial autopsies.22 The results of

scanning/transmission electron microscopy indicated

a median particle diameter of 0.37 :m. In a

1992 study investigating the generation of surgical

aerosols as simulated on bovine tissue, Jewett et al.

reported that most of the aerosols were below 4.2 :m

with a peak occurring at 0.42 :m, as measured by a

10–stage, low–pressure cascade impactor.23

However, in a follow–up investigation evaluating

occupational exposures collected in the breathing

zone (using personal cascade impactors with cut

points at 0.52, 3.5, and 14.8 :m), Heinsohn and

Jewett (1993) reported the detection of hemoglobin

in a smaller percentage of the samples at a particle

size of 0.52 :m (38% versus 90% detected at

14.7 :m).24

The particulate peaks observed during autopsies 2, 4,

and 5 (Figures 3, 8, and 10 of the Met–One results

and Figures 4 and 12 of the Grimm results) indicate

that the application of LEV has a significant effect

on reducing the aerosols produced by the

reciprocating saws. Additionally, the peak observed

during autopsy 2 (use of the pneumatic saw while the

LEV was inoperable) confirms that the reduction in

aerosol emission results from the LEV and not from

the use of the pneumatic saw versus the electric saw.

The aerosol concentrations observed from use of

both saws without LEV can be one to two orders of

magnitude over baseline. The peaks observed from

the personal real–time air samples collected on the

operating technician with the HAM (Figures 9 and

11 of the HAM results) indicate that aerosols

generated by use of the unventilated reciprocating

saws are capable of reaching the breathing zone of

the worker.

The real–time instrumentation compared favorably

with the filter cassette samples collected by the

county health department. As shown in Figure 16,

there is a consistent reduction in the concentration

levels (reported as fragments [as determined by

optical microscopy] per liter of air) between the

application of the electric saw and the pneumatic saw

equipped with LEV. The largest differential is

observed for the right area sample and the personal

breathing zone (PBZ) sample collected on the

forensic technician. The PBZ sample collected on

the pathologist exhibited the lowest differential

margin; the pathologist did not use the reciprocating

saw and was generally located opposite of and

approximately three feet from the forensic

technician. The dissimilar concentrations between

the left and right area samples can be explained by

the direction of air flow in the room. The auxiliary

exhaust units were located in the ceiling nearer to the

entry door of the room. This placement of the

exhaust air vent would cause a pressure differential

resulting in air movement from left to right across the

operating table. Therefore, particles generated by the

application of the reciprocating saw would drift to

the right. 

Noise

The noise data from the two types of reciprocating

saws reveal that the noise levels should not exceed

the evaluation criteria for hazardous noise exposure.

Although levels can approach 95 dB(A), the greatest

15–second sample recorded during the evaluation,

the short amount of time which the physician or

technician are subjected to the noise lowers the

TWA value below all the criteria. Even the most

conservative exposure criteria of NIOSH and the

ACGIH allow exposure to 95 dB(A) for a total time

of slightly less than one hour.20,21 The exposure

times measured in the survey were on the order of

two minutes or less for each autopsy. It is unlikely

that employees would perform 30 autopsies per day.

NIOSH was given a training videotape produced by

the Department of the Coroner which introduced the

audience to the pneumatic saw. In the videotape, a

comparison of the noise emitted by the pneumatic

and electric saws was made with a microphone

placed near the saws and the VU meter of the

microphone’s amplifier in camera view. The level of

energy on the meter was obviously greater for the

electric saw, which seems to be in conflict with the

results found during the NIOSH evaluation. It is

possible that the differences are due to the way in
Health Hazard Evaluation Report No. 96–0019 Page 9

which the comparisons were made. In the Coroner’s

videotape, the saws were allowed to run at full power

in free space, i.e., they were not doing any work.

The NIOSH data were collected during actual

sawing operations. The effect of putting a load on

the saw when it was cutting into bone most likely

changed the acoustical output of the tools. Also, a

higher energy sound component (above 4 kHz) for

the electric model may cause the two types of saws

to sound different to the operator.

CONCLUSIONS

The health care industry poses unique occupational

exposure concerns including exposure to pathogenic

agents in blood and other fluids. HIV has been

shown to remain viable in the cool aerosols

generated by certain surgical tools.25 In addition,

researchers have demonstrated the ability of HIV to

survive several hours to 16 days postmortem and has

been detected several days outside of a host.26,27 Due

to the invasive nature of the procedures used in the

operating theater and the aerosol–generating

potential of specific surgical instruments (i.e.,

harmonic scalpels, electro–cautery knives, lasers, and

reciprocating saws), there is an increased risk of

exposure to aerosols that may contain infectious

agents (i.e., Mycobacterium tuberculosis). These

same risks are encountered during the conduct of

autopsies. Additionally, during an autopsy, the HIV

status of a decedent or the diagnosis of tuberculosis

or other infectious diseases may not be known.

Therefore, it is prudent to evaluate the risks prior to

each case and employ appropriate control strategies

to minimize the potential for occupational exposures.

The objective of this NIOSH investigation was to

determine if the alternative reciprocating saw

(1) generates less tissue and bone fragment aerosol

that could potentially challenge the breathing zone of

the operating forensic technician, and (2) reduces the

noise exposure to the technician and surrounding

personnel. Real-time, light-scattering instruments

were used to monitor transient peaks of generated

particles during the performance of autopsies. For

the NIOSH data, no attempt was made to determine

the exact contribution of blood and/or tissue

fragments to the observed particle concentrations.

However, it can be assumed that the generated

aerosols are predominantly composed of constituents

from the cadaver (i.e., tissue, bone, blood, and

water). In contrast, the filter cassette samples

collected by the county health department were

analyzed for bone and tissue fragments.

The particulate peaks observed during three of the

monitored autopsies conducted without the aide of

LEV indicate that the application of LEV has a

significant effect on reducing the aerosols produced

by the reciprocating saws. Additionally, the peaks

observed from the personal real–time air samples

collected on the operating technician with the

handheld aerosol monitor indicate that aerosols

generated by use of the unventilated reciprocating

saws are capable of reaching the breathing zone of

the worker and are in the respirable size range. The

noise data from the two types of reciprocating saws

reveal that the noise levels should not exceed the

evaluation criteria for hazardous noise exposure.

The extra bulkiness resulting from the extension of

the pneumatic lines and the exhaust ventilation

tubing created a number of ergonomic issues.

Awkward postures imposed by the trailing lines

resulted in a two–fold increase in the time to conduct

the cranial cuts. The ergonomic implications could

result in a lack of acceptance of the modified device

among the professional forensic community.

The application of video recording equipment and

the time synchronization of this equipment to the

real–time instrumentation allowed the identification

of peak concentrations not observable with the filter

cassette data collected by the county health

department. This information can be used to focus

control strategies. For this investigation, the data

from the real–time instrumentation indicated that

aerosols are predominantly generated during the

application of the reciprocating saw. Therefore,

controls applied during the use of reciprocating saw

will have the greatest impact on the generation of

aerosols during the conduct of autopsies.

Additionally, the collected data can be overlaid onto
Page 10 Health Hazard Evaluation Report No. 96–0019

1. Francis J. Curry National Tuberculosis Center

[1996]. On–site consultation report: prevention

and control of tuberculosis at Los Angeles County

Department of Coroner. San Francisco, CA.

2. NIOSH [1988]. Guidelines for protecting the

safety and health of health care workers.

Cincinnati, OH: U.S. Department of Health and

Human Services, Public Health Service, Centers

for Disease Control, National Institute for

Occupational Safety and Health, DHHS (NIOSH)

Publication No. 88–119.

3. CDC (Centers for Disease Control and

Prevention) [1994]. Guidelines for preventing the

transmission of Mycobacterium tuberculosis in

health care facilities. MMWR 43(No. RR–13).

4. CDC (Centers for Disease Control and

Prevention) [1989]. Guidelines for prevention of

transmission of human immunodeficiency virus

and hepatitis B virus to health–care and

public–safety workers. MMWR 38(No. S–6).

5. 56 Fed. Reg. 235 [1991]. Occupational

Safety and Health Administration: occupational

exposure to bloodborne pathogens; final rule. 29

CFR 1910.1030.

6. OSHA [1996]. Enforcement procedures and

scheduling for occupational exposures to

tuberculosis. CPL 2.106. Washington, D.C.: U.S.

Department of Labor, Occupational Safety and

Health Administration, Office of Health

Compliance Assistance.

7. Healing TD, Hoffman PN, Young SEJ

[1995]. The infection hazards of human cadavers.

Communicable Disease Report 5(5):R61–R68.

8. Young SEJ, Healing TD [1995]. Infection in

the deceased: a survey of management.

Communicable Disease Report 5(5):R69–73.

9. Nolte KB, Foucar K, Richmond JY [1996].

Hantaviral biosafety issues in the autopsy room

and laboratory: concerns and recommendations.

Human Pathology 27(12)1253–1254.

10. Sugita M, Tsusumi Y, Suchi M, Kasua H,

Ishiko T [1990]. Pulmonary tuberculosis: an

occupational hazard for pathologists and

pathology technicians in Japan. Acta Pathologica

Japonica 4(2):116–127.

11. Templeton GL, Illing LA, Young L, Cave

MD, Stead WW, Bates JH [1995]. The risk for

transmission of Mycobacterium tuberculosis at the

bedside and during autopsy. Annals of Internal

Medicine 122(12):922–925.

12. Kantor HS, Poblete R, Pusateri SL [1988].

Nosocomial transmission of tuberculosis of

tuberculosis from unsuspected disease. American

Journal of Medicine 84:833–837.

13. Lundgren R, Norrman E, Asberg I [1987].

Tuberculosis infection transmitted at autopsy.

Tubercule 68:147–150.

the video images to be subsequently used as training

aids.

As observed during this investigation, operator error

can result in occupational exposures to aerosols.

Therefore, it is recommended that respirators

continue to be applied under the current program to

protect against inadvertent exposures to infectious

aerosols During the time of the NIOSH

investigation, county coroner department policies

required the use of HEPA filtered particulate halfface respirators (at a minimum; hooded, powered

air-purifying respirators were also available), double

gloves, caps, gowns, and shoe coverings for

autopsies conducted in the “high risk” room. For

respirator use, OSHA requires a respiratory

protection program that includes the following

components: written standard operating procedures,

user instruction and training, cleaning and

disinfection, storage, inspection, surveillance of work

area conditions, evaluation of respirator protection

program, medical review, and use of certified

respirators.28

REFERENCES
Health Hazard Evaluation Report No. 96–0019 Page 11

14. ASHRAE [1991]. Health facilities. In:

ASHRAE Applications Handbook. Atlanta, GA:

American Society for Heating, Refrigerating, and

Air–Conditioning Engineers, Chapter 7.

15. AIA [1987]. Guidelines for construction and

equipment of hospital and medical facilities.

Waldorf, MD: American Institute of Architects.

16. Ward WD [1986]. Anatomy & physiology of

the ear: normal and damaged hearing. Chapter 5.

In: Berger EH, Ward WD, Morrill JC, Royster

LH, eds. Noise & hearing conservation manual.

4th ed. Akron, OH: American Industrial Hygiene

Association, pp 177–195.

17. Suter AH [1978]. The ability of mildly

hearing–impaired individuals to discriminate

speech in noise. Washington, D.C.: U.S.

Environmental Protection Agency, Joint

EPA/USAF study, EPA 550/9–78–100,

AMRL–TR–78–4.

18. Code of Federal Regulations [1992]. OSHA.

29 CFR 1910.95. Washington, DC: U.S.

Government Printing Office, Federal Register.

19. NIOSH [1972]. Criteria for a recommended

standard: occupational exposure to noise.

Cincinnati, OH: U.S. Department of Health,

Education, and Welfare, Health Services and

Mental Health Administration, National Institute

for Occupational Safety and Health, DHEW

(NIOSH) Publication No. 73–11001.

20. Niemeier RW [1995]. Memorandum of April

13, 1995, from R.W. Niemeier, Division of

Standards Development and Technology Transfer,

to NIOSH Division Directors, National Institute

for Occupational Safety and Health, Centers for

Disease Control and Prevention, Public Health

Service, U.S. Department of Health and Human

Services.

21. ACGIH [1997]. 1997 threshold limit values

for chemical substances and physical agents and

biological exposure indices. Cincinnati, OH:

American Conference of Governmental Industrial

Hygienists.

22. Green FHY, Yoshida K [1990].

Characteristics of aerosols generated during

autopsy procedures and their potential role as

carriers of infectious agents. Appl Occup Environ

Hyg 5(12):853–858.

23. Jewett DL, Heinsohn P, Bennett C, Rosen A,

Neuilly C [1992]. Blood–containing aerosols

generated by surgical techniques: a possible

infectious hazard. Am Ind Hyg Assoc

53(4):228–231.

24. Heinsohn P, Jewett [1993]. Exposure to

blood–containing aerosols in the operating room:

a preliminary study. Am Ind Hyg Assoc J

54(8):446–453.

25. Johnson GK, Robinson WS [1991]. Human

immunodeficiency virus–1 (HIV–1) in the vapors

of surgical power instruments. Journal of

Medical Virology 33:47–50.

26. Douceron H, Deforges L, Gherardi R, Sobel

A, Chariot P [1993]. Long–lasting postmortem

viability of human immunodeficiency virus: a

potential risk in forensic medicine practice.

Forensic Science International 60:61–66.

27. Resnick L, Veren K, Salahuddin Z, Tondreau

S, Markham PD [1986]. Stability and inactivation

of HTLV–III/LAV under clinical and laboratory

environments. JAMA 255(14):1887–1891.

28. Code of Federal Regulations [1992]. OSHA

Respiratory Protection. 29 CFR 1910.134.

Washington, DC: U.S. Government Printing

Office, Federal Register.
Page 12 Health Hazard Evaluation Report No. 96–0019

08:52 08:53 08:54 08:55 08:56 08:57 08:58 08:59 09:00 09:01 09:02

Time of Day

1,000

10,000

100,000

1,000,000

C

onc

entration (p

art ci el s L/ )

Saw operating

Particles > 1 μm

Particles > 0.3 μm

Figure 1. Met–One Results of Autopsy 1 (pneumatic saw with LEV)

     













 



  





 



     

 



     

 

      

        

08:55 AM 08:57 AM 08:59 AM 09:01 AM 09:03 AM

Time of Day

0.1

1

10

100

1,000

10,000

100,000

C

o

n

c

e

ntratio

n (p

artic

el s/L)

> 0.75 μm

> 1 μm

> 2 μm

> 2.5 μm

> 3 μm

> 7.5 μm

> 10 μm

> 15 μm

















Saw operating

Figure 2. Grimm Results of Autopsy 1 (pneumatic saw with LEV)
Health Hazard Evaluation Report No. 96–0019 Page 13

10:21 10:22 10:23 10:24 10:25 10:26 10:27 10:28 10:29

Time of Day

100

1,000

10,000

100,000

1,000,000

C

onc

entrat oi n (p

art ci el s/L)

Saw operating

off LEV on

Particles > 0.3 μm

Particles > 1 μm

Figure 3. Met–One Results of Autopsy 2 (pneumatic saw with LEV)

  













  





 







   



 









    













  

     



         



         

10:24 AM 10:26 AM 10:28 AM 10:30 AM 10:32 AM 10:34 AM

Time of Day

0.1

1

10

100

1,000

10,000

100,000

C

o

n

c

e

ntratio

n (p

artic

el s/L)

> 0.75 μm

> 1 μm

> 2 μm

> 2.5 μm

> 3 μm

> 7.5 μm

> 10 μm

> 15 μm

















Saw operating

Figure 4. Grimm Results of Autopsy 2 (pneumatic saw with LEV)
Page 14 Health Hazard Evaluation Report No. 96–0019

13:10 13:11 13:12 13:13 13:14 13:15 13:16 13:17 13:18 13:19

Time of Day

1,000

10,000

100,000

1,000,000

C

o

n

c

e

ntrat oi n (p

art ci el s

L/ )

Saw operating

Particles > 1 μm

Particles > 0.3 μm

Figure 5. Met–One Results of Autopsy 3 (pneumatic saw with LEV)

13:10 13:11 13:12 13:13 13:14 13:15 13:16 13:17 13:18 13:19 13:20

Time of Day

0

0.5

1

1.5

2

A

ero

s

ol C

o

n

c

e

ntrat oi n

m( g

m/ 3)

Saw operating

Figure 6. PBZ HAM Results of Autopsy 3 (pneumatic saw with LEV)
Health Hazard Evaluation Report No. 96–0019 Page 15

  

















  



   











   

 

  



     

 

 



 

            





                



                

01:04 PM 01:07 PM 01:10 PM 01:13 PM 01:16 PM 01:19 PM

Time of Day

0.1

1

10

100

1,000

10,000

100,000

C

o

n

c

e

ntrat oi n (p

art ci el s

L/ )

> 0.75 μm

> 1 μm

> 2 μm

> 2.5 μm

> 3 μm

> 7.5 μm

> 10 μm

> 15 μm

















Saw operating

Figure 7. Grimm Results of Autopsy 3 (pneumatic saw with LEV)
Page 16 Health Hazard Evaluation Report No. 96–0019

08:45 08:46 08:47 08:48 08:49 08:50 08:51 08:52 08:53 08:54 08:55

Time of Day

1,000

10,000

100,000

1,000,000

C

o

n

c

e

ntrat oi n (p

art ci el s/L)

Saw operating

Particles > 1 μm

Particles > 0.3 μm

Figure 8. Met–One Results of Autopsy 4 (Electric saw)

08:45 08:46 08:47 08:48 08:49 08:50 08:51 08:52 08:53 08:54 08:55

Time of Day

0

0.5

1

1.5

2

A

ero

s

ol C

o

n

c

e

ntrat oi n

m( g

m/ 3)

Saw operating

Figure 9. PBZ HAM Results of Autopsy 4 (Electric saw)
Health Hazard Evaluation Report No. 96–0019 Page 17

10:50 10:51 10:52 10:53 10:54 10:55 10:56 10:57 10:58 10:59

Time of Day

1,000

10,000

100,000

1,000,000

C

onc

entrat oi n (p

art ci el s L/ )

Saw operating

Particles > 1 μm

Particles > 0.3 μm

Figure 10. Met–One Results of Autopsy 5 (Electric saw)

10:50 10:51 10:52 10:53 10:54 10:55 10:56 10:57 10:58 10:59

Time of Day

0

0.5

1

1.5

2

A

ero

s

ol C

onc

entrat oi n m( g

m/ 3)

Saw operating

Figure 11. PBZ HAM Results of Autopsy 5 (Electric saw)
Page 18 Health Hazard Evaluation Report No. 96–0019

   













   





















 





















 





         











 



 







 





 





10:36 AM 10:40 AM 10:44 AM 10:48 AM 10:52 AM 10:56 AM

Time of Day

0.1

1

10

100

1,000

10,000

100,000

C

o

n

c

e

ntrat oi n (p

art ci el s

L/ )

> 0.75 μm

> 1 μm

> 2 μm

> 2.5 μm

> 3 μm

> 7.5 μm

> 10 μm

> 15 μm

















Saw operating

Figure 12. Met–One Results of Autopsy 5 (Electric saw)
Health Hazard Evaluation Report No. 96–0019 Page 19

11:30 11:31 11:32 11:33 11:34 11:35 11:36 11:37 11:38 11:39 11:40

Time of Day

100

1,000

10,000

100,000

1,000,000

C

onc

entrat oi n (p

art ci el s/L)

Saw operating

Particles > 1 μm

Particles > 0.3 μm

Figure 13. Met–One Results of Autopsy 6 (pneumatic saw with LEV)

11:30 11:31 11:32 11:33 11:34 11:35 11:36 11:37 11:38 11:39 11:40

Time of Day

0

0.5

1

1.5

2

A

ero

s

ol C

o

n

c

e

ntrat oi n

m( g

m/ 3)

Saw operating

Figure 14. PBZ HAM Results of Autopsy 6 (pneumatic saw with LEV)
Page 20 Health Hazard Evaluation Report No. 96–0019

  































  



































 

 









































































 











































































 















































  









11:35:00 AM 11:36:00 AM 11:37:00 AM 11:38:00 AM 11:39:00 AM 11:40:00 AM

Time of Day

0.1

1

10

100

1,000

10,000

100,000

C

o

n

c

e

ntrat oi n (p

art ci el s

L/ )

> 0.75 μm

> 1 μm

> 2 μm

> 2.5 μm

> 3 μm

> 7.5 μm

> 10 μm

> 15 μm

















Saw operating

Figure 15. Met–One Results of Autopsy 6 (pneumatic saw with LEV)

Area (left) Area (right) PBZ Forensic

Technician

PBZ Pathologist

0

0.01

0.02

0.03

0.04

0.05

C

onc

entrat oi n (fra

g

m

ents/c

c)

Stryker saw

Pneumatic saw with LEV

Figure 16. Filter Cassette Sampling Results Comparing Bone and Tissue

Fragment Concentrations for Different Reciprocating Saws.
Health Hazard Evaluation Report No. 96–0019 Page 21

8 16 32 64 125 250 500 1k 2k 4k 8k 16k

One-Third Octave Band Frequency [Hz]

0

20

40

60

80

100

Noise Level [dB re. 20 m ci ropasca sl ]

Pneumatic: overall levels - 90.9 dB(A), 90.7 dB SPL

Stryker: overall levels - 92.1 dB(A), 92.7 dB SPL

Figure 17. Noise Levels for Pneumatic versus Electric Saw

8 16 32 64 125 250 500 1k 2k 4k 8k 16k

One-Third Octave Band Frequency [Hz]

0

20

40

60

80

100

Noise Level [dB re. 20 m ci ropasca sl ]

Overall Level - 86.0 dB(A)

 86.6 dB SPL

Figure 18. Noise Levels for HEPA Vacuum and Recovery System
Page 22 Health Hazard Evaluation Report No. 96–0019

8 16 32 64 125 250 500 1k 2k 4k 8k 16k

0

20

40

60

80

100

8 16 32 64 125 250 500 1k 2k 4k 8k 16k

One-Third Octave Band Frequency [Hz]

0

20

40

60

80

100

Saw Operational 90.8 dB(A) 91.0 dB SPL

No Fluid 94.8 dB(A) 94.4 dB SPL

8 16 32 64 125 250 500 1k 2k 4k 8k 16k

0

20

40

60

80

100

N

ois

e

L

e

v

el [d

B re. 2

0

micro

p

a

s

c

a

sl ]

No Fluid or Vacuum 93.5 dB(A) 93.2 dB SPL

Figure 19. Noise Levels for First 15–second Pneumatic Saw Samples
Delivering on the Nation’s promise:

Safety and health at work

For all people

Through research and prevention