Based on the results of the audiometric data analyses, as well as the potential for high

level noise exposures in the PBF, the NIOSH investigator concludes that a health hazard

exists for fire fighters in the PBF. A statistically significant relationship was found

between the amount of hearing loss and the time spent in the department after the data

were corrected for age using correction factors published in the Occupational Safety and

Health Administration's noise regulation. Section IX of this health hazard evaluation

report offers recommendations to the PBF which can reduce the noise exposures to the

fire fighters and help prevent further hearing losses.

HETA 88-0290-2460 NIOSH INVESTIGATOR: 

SEPTEMBER 1994 RANDY L. TUBBS, Ph. D.

PITTSBURGH BUREAU OF FIRE

PITTSBURGH, PENNSYLVANIA

I. SUMMARY

On June 2, 1988, the International Association of Fire Fighters' (IAFF) Department of Health and Safety

requested the National Institute for Occupational Safety and Health (NIOSH) to conduct a Health Hazard

Evaluation (HHE) on behalf of their Local #1 in Pittsburgh, Pennsylvania. The request was to evaluate the

noise exposure levels found in the activities of the Pittsburgh Bureau of Fire (PBF) and to assess the amount

of hearing loss among current fire fighters in the department.

Noise dosimeter surveys were conducted at 18 of the 36 total fire stations during the weeks of

September 12, and October 3, 1988. The Bureau's fire apparatus assigned to the 36 fire stations in

Pittsburgh were driven in simulated emergency runs July 17-19, 1990, in order to tape record the noise

levels emitted by the vehicles for later one-third octave band spectral analysis. The third phase of the

evaluation, audiometric testing, was completed on 424 PBF fire fighters from January 9-20, 1989.

The noise surveys revealed that the 8-hour time-weighted average (TWA) noise exposures were generally

less than the amount allowed under any of the environmental evaluation criteria used by NIOSH. However,

portions of the noise analyses found noise levels that greatly exceeded the exposure limits for brief periods

of time. These high exposures were usually associated with emergency response runs in the fire vehicles.

The statistical tests performed on the audiometric data showed a statistically significant relationship between

the time spent with the PBF and the amount of hearing loss in fire fighters after the effects of age had been

corrected from the hearing levels. The effects on hearing were seen in the audiometric test frequencies most

sensitive to noise insult, as well as in the frequencies used in human speech perception.

KEYWORDS: SIC 9224 (Fire departments, including volunteer), noise exposure, noise dosimetry, fire

apparatus noise, hearing loss, hearing conservation.

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. INTRODUCTION

On June 2, 1988, the International Association of Fire Fighters' (IAFF) Department of Health and Safety

requested the National Institute for Occupational Safety and Health (NIOSH) to conduct a Health Hazard

Evaluation (HHE) on behalf of their Local #1 in Pittsburgh, Pennsylvania. The request was to evaluate

noise exposure and hearing loss among fire fighters at the Pittsburgh Bureau of Fire (PBF). On August 17,

1988, an opening conference was held at the Bureau's headquarters in Pittsburgh where the Bureau

expressed an interest in the project and stated that a cooperative effort with the local union should be

undertaken.

A three-phased approach to investigate the noise levels and the hearing levels found in the PBF was agreed

on by all parties during the opening conference; (1) noise dosimetry on the daywatch shifts at half of the fire

stations staffed by the PBF; (2) spectral measurements of the noise from vehicles used by the PBF; and

(3) audiometric evaluations of approximately half of the Bureau's fire suppression manpower. The results

from each phase were provided to union and management officials through letters and interim reports. The

results of the noise dosimetry at the fire stations was provided in an interim report dated November 14,

1988. Individual fire fighters were provided the results of their hearing tests by letter on February 10,

1989, and summary results of the audiometric examinations were provided to union and management

officials on February 17, 1989. Finally, the vehicle noise levels were reported by letter on August 14,

1990. This final report presents a summary of the previously reported results and a more thorough analysis

of the data than that provided in the earlier reports.

III. BACKGROUND

The PBF is responsible for providing fire suppression and prevention services along with "first responder"

emergency medical services to the 56 square miles of city and 370,000 people of Pittsburgh, Pennsylvania. 

Thirty-six fire stations located throughout the city house the Bureau's fleet of fire apparatus and 960 fire

fighters. The stations are staffed 24 hours per day, seven days per week by fire fighters working either a

daywatch or nightwatch shift. The 960 fire fighters are divided into four groups, or lines, to cover the

stations at all times.

IV. MATERIALS AND METHODS

A. Dosimetry

Noise dosimeter surveys were conducted during the weeks of September 12, and October 3, 1988. 

During the two weeks, a total of 18 fire stations were surveyed on two consecutive days for 8 hours

each day during the daywatch shift. During the survey days, a NIOSH industrial hygienist was at a

surveyed station during the entire 8-hour sampling period. The hygienist was issued turnout gear by

the PBF and rode the vehicles whenever they left the station in one of the extra jumpseat positions on

the vehicle. A detailed time log was kept by the hygienist so that the time of the responses could be

calculated and also any noisy events could be noted. The stations were selected so that representative

vehicles used by the PBF were included in the stations sampled. Whenever possible, the busiest
Page 3 - Health Hazard Evaluation Report No. 88-0290

stations in the city (based on 1987 run records) were chosen to maximize the likelihood that the

vehicles would be called out for response to emergency situations.

Members of the crew assigned to a vehicle were asked to wear a noise dosimeter for 8 hours of their

work shift. If they were required to put on their turnout gear for an emergency response, the fire

fighters were reminded to place the microphone of the dosimeter outside of the turnout gear, exposing

it to the noise environment. The noise dosimeters used in this phase were Metrosonic Model

dB301/26 Metrologgers, a small noise level recording device worn on the waist of the fire fighter with

a 1/4 inch remote microphone placed on the shirt collar of the station uniform. This dosimeter

measures noise in decibels, A-weighted levels (dB[A]) four times per second. The measurements are

integrated according to the Occupational Safety and Health Administration (OSHA) noise regulation

(see Evaluation Criteria section of this report) for an entire minute and stored separately in the

Metrologger for data storage and later analysis. Generally, five or six dosimeters were placed on the

fire fighters assigned to the surveyed station house.

Each dosimeter was calibrated according to the manufacturer's instructions before being placed on a

fire fighter. After the shift was completed, the dosimeter was removed from the fire fighter and placed

in the standby mode of operation. Once the data had been transferred to a computer for storage, the

dosimeter was again calibrated to assure the electronics of the device had not changed during the

sampling period. The data from each Metrologger dosimeter was transferred to a Metrosonics Model

dt-390 Metroreader/Data Collector following the day's noise sampling. The information was then

transferred to a NEC Laptop Computer with a Metrosonics' Metrosoft software package for

permanent data storage and later analysis.

B. Vehicle Spectrum Measurements

The Bureau's fire apparatus assigned to each of the 36 fire stations during the July 17-19, 1990, testing

period were brought either to an undeveloped area along the riverfront or to Three Rivers Stadium for

data collection. The data collection consisted of tape recording the sounds from the vehicle; such as

engine noise, sirens, and air horns; from the riding positions of the vehicles with a Panasonic Model

SV-250 Digital Audio Tape (DAT) Recorder. Additional data were collected with a Larson-Davis

Model 800B Integrating Sound Level Meter at each riding position. The data from the sound level

meter were recorded on data sheets. The tape recordings were later analyzed with a GenRad Model

1995 Integrating Real-Time Analyzer to produce intensity by frequency (spectral) graphs which

describe the predominate sounds on the vehicles.

Recordings were obtained over a 30-60 second period when lights, sirens, and air horns (if available)

were operating with the vehicle driven on the streets simulating an emergency run for the fire

apparatus. Measurements of engine noise without warning devices operating were also stored on the

DAT recorder while the vehicle was driven. The vehicles were driven at speeds of 35-50 miles per

hour during the recording period. Noise measurements were made in each of the riding positions of

the apparatus; normally, the cab and tailboard or jumpseat for an engine; the cab and jumpseat and

tiller, where appropriate, for the trucks; and the front and back seats of squad and battalion chief cars.
Page 4 - Health Hazard Evaluation Report No. 88-0290

C. Audiometric Testing

The audiometric tests were administered by a Council for Accreditation in Occupational Hearing

Conservation (CAOHC) certified occupational hearing conservationist. Testing was conducted in the

basement of a centrally located fire station where an Acoustic Systems Model RE-60 Transportable

Sound Booth was assembled to isolate the fire fighter during the testing procedure and keep the

ambient noise levels to a minimum. Audiometric testing was done with a Tracor Model RA400

Microprocessor Audiometer, which also allowed for the electronic storage of the audiometric results. 

The audiometric data were downloaded daily to a NEC laptop computer for permanent storage and

later analysis.

Engine and truck companies reported to the test site every 45 minutes for audiometric testing. 

Informed consent was obtained from each fire fighter prior to testing. Additionally, a short, selfadministered work history questionnaire (Appendix 1) was completed by the participants prior to

taking the audiometric examination. Following a brief set of instructions about the hearing test

procedure, pure-tone audiometric thresholds were obtained from the fire fighters at 500, 1000, 2000,

3000, 4000, 6000, and 8000 Hertz (Hz) separately for each ear, beginning with the left ear. Total test

time was approximately 10 minutes per person. The audiometer was given an exhaustive calibration

by a manufacturer's representative laboratory immediately prior to this HHE. Daily biological

calibrations were made with a Tracor Oscar II electro-acoustic ear. The results of the audiometric

examination were briefly reviewed with each fire fighter by the Project Officer immediately following

the test.

V. EVALUATION CRITERIA

A. 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.1 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.2
Page 5 - Health Hazard Evaluation Report No. 88-0290

The A-weighted decibel (dBA) 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 1,000 Hz). Decibel units are used because of the very

large range of sound pressure levels which are audible to the human ear. The dBA scale is weighted

to approximate the sensory response of the human ear to sound frequencies. Because the dBA scale

is logarithmic, increases of 3 dBA, 10 dBA, and 20 dBA, represent a doubling, tenfold increase, and

100-fold increase of sound levels, 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)3 specifies a maximum

Permissible Exposure Limit (PEL) of 90 dB(A)-slow response for a duration of 8-hours per day. The

regulation, in calculating the PEL, uses a 5 dB time/intensity trading relationship. This means that in

order for a person to be 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. Both

NIOSH, in its Criteria for a Recommended Standard,4 and the American Conference of

Governmental Industrial Hygienists (ACGIH), in their Threshold Limit Values (TLV®s),5 propose an

exposure limit of 85 dB(A) for 8 hours, 5 dB less than the OSHA standard. Both of these latter two

criteria also use a 5 dB time/intensity trading relationship in calculating exposure limits.

TWA noise limits as a function of exposure duration are shown as follows:

Sound Level dB(A) 

Duration of Exposure (hrs/day) NIOSH/ACGIH OSHA

16 80 85

8 85 90

4 90 95

2 95 100

1 100 105

1/2 105 110

1/4 110 115*

1/8 115* ---

**

* 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.
Page 6 - Health Hazard Evaluation Report No. 88-0290

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.

B. Audiometry

The audiometric test results obtained for the fire fighters were combined according to two different

criteria to determine the degree of hearing handicap that had been sustained. Additionally, a singlefrequency, degree of hearing impairment criterion was used to initially screen the data to determine the

amount of hearing loss found in this population. The first criterion was proposed by NIOSH in its

criteria document for occupational noise exposure.4 This criterion, which is intended to determine the

amount of handicap in speech perception and communication abilities, averages the hearing level in

decibels (dB HL re ANSI S3.6-1969)6 at the pure-tone frequencies of 1000, 2000, and 3000 Hz for

both ears. This measurement will be referred to in this report as the "mid-frequency" variable. The

criterion incorporates a 25 dB "low fence" value. This means that the dB HL average value must

exceed 25 dB before a hearing impairment is said to exist. The percentage of impairment is calculated

by multiplying each decibel in excess of 25 dB HL by 1.5%. For example, an average dB HL of 40

for the "mid-frequency" variable would represent a 22.5% hearing impairment.

The second variable used in this report has been proposed by the American Academy of

Otolaryngology - Head and Neck Surgery.7 The criterion combines the pure-tone frequencies of

3000, 4000, and 6000 Hz. This combination will be most sensitive to the sensorineural effects on the

ear from noise because of the propensity of these frequencies to deteriorate sooner when exposed to

loud noises.8 For this report, the second criterion will be called the "high-frequency" variable.

Finally, a criterion proposed by Eagles, et al.9 for single-frequency hearing impairment determination

also uses a low fence of 25 dB HL. With this criterion, any person who had a hearing level of 26 dB

HL or greater at any single frequency was classified as having some degree of hearing loss. The

degree of loss could range from "mild" (26-40 dB HL) to "profound" (> 90 dB HL). This criterion

differs from the other two criteria in that it looks at single test frequencies rather than average hearing

levels across several frequencies.

Additional analyses were conducted on the first two criteria after the data had been adjusted for the

effects from normal aging processes (presbycusis). In order to do this, the hearing level data were

corrected according to the formula described by NIOSH4 in its criteria document. The formula uses

the presbycusis curves for a male population which have been published in the Department of Labor's

noise regulation.3
Page 7 - Health Hazard Evaluation Report No. 88-0290

VI. RESULTS

A. Dosimetry

During the two weeks of noise sampling, a total of 18 station houses were surveyed over two

consecutive daywatch work shifts in each of the stations. All surveyed houses consisted of an engine

company and either a truck company or a squad company. Station #24 consisted of all three types of

companies. A total of 170, 8-hour noise dosimeter samples were collected and stored for later

analysis.

The dosimeter results for the engine, truck, and squad companies are given in Tables 1, 2, and 3,

respectively. Each of these tables give the company number, the date of noise dosimeter testing, and

the total number of times when the vehicle left the station house (responses) and how many of these

responses were emergency in nature with sirens and/or air horns operating. The noise data are

presented as a percentage of a daily noise dose according to OSHA regulations, which stipulates a

maximum daily dose of 100%. If a fire fighter receives less than 100% of a dose during his or her

work shift, the employee is within current OSHA regulations. If the dose exceeds 100%, then the fire

fighter is over-exposed to noise on that particular day according to OSHA regulation. Three shift

periods are given in these tables. The 8-hour column represents the period of sampling conducted by

NIOSH. The 10-hour and 14-hour columns are linear interpolations of the data for the daywatch

(10-hour shift) and nightwatch (14-hour shift) periods used by the PBF. These later two columns

represent the amount of dose a fire fighter would accumulate if the 8-hour sampling period were

representative of a longer work shift, i.e., the same noise events would occur at the same rate for the

longer time periods. Finally, a column labeled "Maximum" is the greatest one minute average dB(A)

level recorded for any of the fire fighters assigned to the vehicle on the sampling day. It represents a

short term exposure period indicative of siren noise, air horn noise, or equipment testing noise.

Inspection of the dosimeter data reveals that the large majority of the averaged daily noise levels were

below 100% of a daily allowable dose. None of the truck companies or squad companies had daily

average doses in excess of 100%. There were three instances where an engine company was in

excess of 100%. Of these three occurrences, one was recorded at the training academy for drivers'

training on the Pierce Tiller truck. The other two were recorded when one of the companies had

pump testing in the morning and a fire in the afternoon (Station #11) and the other recorded average

was at a station with the highest number of responses recorded during the survey period (Station #33). 

Generally, the recorded noise levels were less than 50% of the daily allowable dose for all of the

vehicles surveyed.

The recorded maximum one-minute periods did, however, reveal that the potential for high levels of

noise exposure does exist in the PBF as levels of 105 to 120 dB(A) were consistently found in all

three types of companies. It is believed that these higher exposure periods are associated with siren,

air horn, or equipment noise. In the example in Figure 1, the two separate periods of high noise

exposure levels seen at the 3-hour, 15-minute mark and 6-hour, 30-minute mark are both the result of

noise levels recorded during emergency responses.
Page 8 - Health Hazard Evaluation Report No. 88-0290

B. Vehicle Spectrum Measurements

The noise data from the simulated emergency response runs collected with the DAT recorder were

initially reviewed to ascertain that the recorded sound levels were clean, i.e., the recordings were free

of static or peak clipping. Additionally, it was determined if the sound noticeably increased or

decreased during the test period which would indicate the volume control on the recorder may have

been accidentally changed. Finally, pre- and post-calibration tones placed on the tape were

compared to assure that they were the same value. This cursory review resulted in spectral analyses

done for the following PBF vehicles: seven, 1988 Pierce Rear Mount trucks; nine, 1986 Pierce

engines; three, 1988 Pierce Tiller trucks; one, 1989 Pierce Lance engine; four, 1978 Brockway

engines; ten, 1981-82 Grumman engines; four, 1973-74 Mack engines; four, 1984 Thibault Rear

Mount trucks; one, 1977 Seagrave Rear Mount truck; one, 1976 Seagrave Tiller truck; one, 1982

Seagrave Front Mount truck; and seven, squad and battalion chief vehicles, consisting of 1986 Dodge

or Chevrolet Suburbans.

The median dB(A) sound levels were calculated from the one-third octave spectral data. These

results are shown in Table 5. The data are presented for the different riding positions and warning

signal conditions. The median dB(A) values range from 79.8 dB(A) for the tailboard riding position

with no warning signals on a Grumman engine to a high value of 113.2 dB(A) in the cab of a Mack

engine when the siren and air horn are operating. As expected, the dB(A) values were higher when

warning signals were operational. Also, the noise levels were found to be generally higher in vehicles

where the jumpseat riding positions were next to the vehicle's engine.

Figures 2-24 plot the median one-third octave band sound levels for each of the vehicle types under

the various test conditions. The detailed presentation of the data shows the differences in vehicle noise

emissions when the recordings are done in cabs, jumpseats, or tailboard and if the warning devices are

operational or not. The noise levels from the Pierce engines (Figures 2-3) show that the engine noise

is maximum at the 160 Hz one-third octave band and can reach levels of 110 dB in the jumpseat. The

mechanical siren and air horn show the most sound energy in the 500 - 5000 Hz range, with a

maximum at 1000 Hz. Similar data were recorded for the Pierce Rear Mount and Tiller trucks

(Figures 12-16). The mechanical siren and air horn noise has a maximum level at the 1000 Hz band. 

The engine noise is one band lower, with the 125 Hz one-third octave band showing the greatest noise

energy. Sound levels for the engine noise are also approaching 110 dB for the Pierce trucks. The

PBF's foam unit, a Pierce Lance (Figures 4-5), does show a noise reduction for the two riding

positions. No median one-third octave band sound level exceeded 100 dB and the majority of the

band levels were below 90 dB.

The noise levels for the PBF's other engines, Grumman, Brockway, and Mack, are shown in Figures

6-11. These three types of vehicles are characterized as having a riding position on the tailboard at the

back of the pumper instead of a jumpseat next to the vehicle's engine. The tailboard position is quieter

as evidenced in the plots for the no warning siren conditions. Two different types of sirens are used on

these engines; the Grumman and Mack engines use a mechanical siren while the Brockway engine has

an electronic siren mounted on a lightbar over the cab. The Brockway engines also did not have air

horns installed. All three of these vehicles do not show a strong influence of engine noise in the

spectral plots, but do show warning signal noise in the middle frequencies. The Brockway engines

with the electronic sirens do have a narrower range of increased sound levels from the siren as
Page 9 - Health Hazard Evaluation Report No. 88-0290

compared to the vehicles with the mechanical sirens and air horns. All three types of engines have

median noise levels from siren exposure that exceed 100 dB.

The trucks in the PBF fleet, other than the Pierce models, are fewer in number. With the exception of

the Thibault Rear Mount truck, the spectral plots represent only one example of the vehicle type. For

the Thibault truck (Figures 17-18), a pattern of engine noise having maximum energy at or near the

125 Hz one-third octave band and warning signal noise from 400 - 4000 Hz is seen. Overall, the

noise energy for this model is less than other trucks and engines, with a majority of the one-third

octave band levels less than 90 dB. In should be noted that the Thibault trucks were equipped with an

electronic siren system that placed the speaker below the front bumper. The loudest vehicle tested in

the PBF fleet was a Seagrave Tiller truck, an open cab vehicle with a mechanical siren mounted in the

center front of the cab, directly below the windshield. Siren noise in excess of 110 dB was recorded

for the one-third octave bands from 800 - 1600 Hz (Figure 20). The noise levels recorded in the

department's squad vehicles and battalion chief's cars are shown in Figure 24. The major noise source

seen for these types of vehicles is the electronic siren, with a very discernable peak in the middle

frequencies.

C. Audiometry

Hearing tests were performed on 424 fire fighters with the PBF who were assigned to the 18 fire

stations that had been involved in the noise dosimetry phase of the evaluation. Personnel from all four

shifts reported to a central location for audiometric testing during their work shift. All but two fire

fighters took part in the audiometric testing.

The PBF fire fighters were predominately male, with only two females included in the 424 tested

individuals. They had a mean age of 41 years, ranging from 23 to 64 years of age, and a mean time at

their job of 14 years with a range of 1 to 39 years of service. The information provided in the

questionnaire revealed that for 56 of the fire fighters, the PBF was their first and only job. With regard

to non-occupational sources of noise exposure, approximately 63% of the group did not hunt or use

firearms, 71% had not ridden motorcycles, and 96% had not used farm machinery. Chain saws had

been used by 57% of the fire fighters and woodworking was a hobby for 33% of them. Seventy-three

percent of the group reported no medical problems in the past with their ears, but 35% did report

tinnitus ("ringing in the ears") and 29% reported a noticeable change in their hearing over the years.

The fire fighters were categorized into six years-of-fire-service groupings in order to analyze the

hearing level data. The categories and the number of individuals in each are as follows: less than six

years of service (N=76); 6-10 years of service (N=86); 11-15 years of service (N=114); 16-20

years of service (N=50); 21-25 years of service (N=63); and over 25 years in the fire service

(N=35). The audiometric data were initially compared to the single test frequency criterion that labels

hearing ability from normal to profound loss.5 Hearing tests were scored according to the worst

hearing level recorded, regardless of the ear or frequency. The comparison is shown in Figure 25. 

The "normal" category shows a general decline in the percentage of fire fighters who fall into this

classification as the number of years in the fire service increases, going from 40% for the less than six

years of service group to 0% for anyone with more than 20 years of service. The converse

relationship is seen for the "severe" loss category, where less than 10% of fire fighters with less than 10
Page 10 - Health Hazard Evaluation Report No. 88-0290

years of service are included, but more than 40% of them with more than 25 years experience have a

severe loss at one or more audiometric test frequencies.

The mean hearing level results for each ear of the 424 tested fire fighters at each test frequency are

presented in Figure 26. The hearing pattern for the entire group shows a trend of progressively worse

hearing as the audiometric test frequency increases from 2000 Hz to 6000 Hz with a slight

improvement at 8000 Hz. The hearing ability for the left ears of the fire fighters is generally poorer

than the right ears; however, this difference is small. Because of the small difference, the hearing levels

of individuals at each audiometric test frequency were averaged for the left and right ears. Figures 27

and 28 show the hearing levels for the 424 fire fighters when categorized by chronological age and by

years of fire service, respectively. The same trends are seen in both figures. Hearing ability

progressively gets worse as the fire fighters age or spend more time in the fire service, with the greatest

changes occurring at 3000, 4000, 6000, and 8000 Hz. A decline in hearing such as seen in the PBF

fire fighters tested is characteristic of a noise-induced permanent threshold shift (NIPTS).1,8

A Pearson product-moment correlation coefficient between the fire fighters' ages and the amount of

time they had spent in the fire service was calculated as +0.87, a statistically significant positive

relationship. Thus, before additional statistical analyses were performed on these data, the age-related

hearing loss, or presbycusis, was subtracted from the effects due to time on the job. The correction

was done by using the age correction values for males published in the OSHA noise regulation.3 The

corrections attempt to subtract the portion of hearing loss that is likely the result of aging from the

audiometric test results, leaving a residual loss that is presumed to be from the effects of noise. The

two female fire fighters tested were not included in these last statistical analyses.

In order to complete the statistical analyses, the two combination variables discussed in the Evaluation

Section of this report were calculated. The "mid-frequency" variable averaged the hearing levels of

1000, 2000, and 3000 Hz and the "high-frequency" variable averaged 3000, 4000, and 6000 Hz. 

The single-factor independent variable, the years-of-fire-service, was divided into its six levels and an

analysis of variance (ANOVA) was calculated to separately analyze each of the two dependent

variables. Statistically significant differences between years-of-fire-service groupings were found for

each of the dependent measures. For the high-frequency variable, a statistically significant F ratio of

3.13 (p < 0.0087) was calculated. The ANOVA for the mid-frequency variable also resulted in a

statistically significant F ratio of 6.87 (p < 0.0001). A Sheffé post-hoc trend test of the differences

between means for each of the six years-of-fire-service groupings was conducted to see where the

significant differences occurred. The groups were labeled as follows: group 1, <= 5 yrs.; group 2, 6-

10 yrs.; group 3, 11-15 yrs.; group 4, 16-20 yrs.; group 5, 21-25 yrs.; and group 6, > 25 yrs. For

the mid-frequency dependent variable, the two fire service groups representing the fire fighters with the

most time on the job were significantly different from the other four fire service groups, with one

exception. The exception to this was that fire service group 5 did not differ from group 4, while group

6 did differ from group 4. There were no significant differences between groups 1, 2, 3, and 4. The

mean values of the mid-frequency variable for each of the six fire service groups, from group 1 to

group 6, were 3.6 dB HL; 2.2 dB HL; 4.3 dB HL; 6.2 dB HL; 7.0 dB HL; and 12.7 dB HL,

respectively. For the high-frequency variable, the only significant difference found was between group

6 (> 25 yrs.) and group 2 (6-10 yrs.) on the Sheffé post-hoc trend test. The means for the highfrequency variable were 10.8 dB HL; 7.7 dB HL; 10.2 dB HL; 14.0 dB HL; 14.3 dB HL; and 18.3

dB HL for group 1 to group 6.
Page 11 - Health Hazard Evaluation Report No. 88-0290

VII. DISCUSSION

The 8-hour TWA noise exposures measured at 18 of the fire stations during the daywatch were

consistently less than the OSHA PEL for noise. Even when the dose percentages were linearly interpolated

to the 10- and 14-hour shifts employed by the PBF, only three of the 74 averaged noise dosimeter readings

exceeded the 100% permissible dose levels. One of the three averaged noise exposure readings were

associated with training exercises on a new fire vehicle, which would not be classified as a routine

occurrence. These survey finding are not unusual. Similar results have been reported in other NIOSH

evaluations of fire departments in the U.S.10,11 

The results from the dosimeter survey and from the spectral analyses of the fire apparatus do, however,

show a potential for high levels of noise from the operation of the fire apparatus. The plot of the daily noise

exposure (Figure 1) clearly shows that emergency responses are associated with high noise exposures for

the fire fighters riding in the vehicle. This finding is confirmed by the spectral analyses conducted on the

PBF's vehicles during simulated emergency responses. Median noise levels in excess of 90 dB(A) were

common for the various riding positions and warning signal conditions tested on the department's fleet of

vehicles. Most of the high readings were the result of the use of sirens and air horns, but a few of the high

noise readings were also obtained when no warning devices were in use. The spectral levels reported are

integrated measurements over a 30 - 60 second time period when the vehicles were in motion and not peak

noise levels measured during the simulated runs. Thus, the potential for even higher peak noise levels exists

for the PBF fire fighters. A noise level of 90 dB(A) is used by the National Fire Protection Association

(NFPA) in its safety and health standard as the not-to-exceed limit where fire fighters are required to wear

hearing protection devices.12

The hearing tests on 424 of the PBF fire fighters represent nearly one-half of the department's fire

suppression personnel. The audiometric data obtained from this group is indicative of people who have

been exposed to excessive noise levels during their lifetime. The characteristic noise notch at 3000, 4000,

and 6000 Hz is seen in all of the audiometric data, regardless if it is presented by the age of the fire fighter

or by the length of service in the fire department. The high-frequency hearing losses increase with

increasing time. The results of the ANOVA statistical tests of the audiometric data show that the average

hearing levels of these fire fighters are significantly changed as a function of the time spent on the job as a

fire fighter. The progressive loss of hearing over time is seen in both the audiometric frequencies sensitive to

noise exposure, as well as the frequencies instrumental in hearing speech. An association between hearing

losses and time spent on the job as a fire fighter has also been previously reported.10,13

VIII. CONCLUSIONS

The statistical analysis of the audiometric data of the PBF personnel confirms that the fire fighters risk

occupational hearing losses as a result of their jobs. The characteristic pattern of a progressive loss of high

frequency hearing ability as the fire fighters grow older or spend more time in the fire service is consistent

with exposure to hazardous noise levels. The noise survey data add additional evidence to this conclusion

by showing that the potential for high levels of noise exist in the department. The daily exposure to these

levels of noise results in an average loss of hearing of 18 dB, after accounting for the effects of age, among

fire fighters who have spent over 25 years in the department.
Page 12 - Health Hazard Evaluation Report No. 88-0290

IX. RECOMMENDATIONS

The results of the health hazard evaluation reveal that fire fighters in the PBF risk an occupational loss of

hearing resulting from their job. Both the audiometric data analyses and the noise survey data are consistent

with this conclusion. Although sensori-neural hearing loss is generally irreversible, additional loss of hearing

from exposure to excessive noise can be prevented. The following recommendations are offered to help

reduce the amount of noise to which the fire fighters are exposed and to set up surveillance programs to

track the hearing ability of current and future fire fighters in order to implement changes to reduce the

hearing losses associated with their jobs.

1. The PBF should implement a hearing conservation program for their department. At a minimum, the

program should follow all of the requirements of OSHA's hearing conservation amendment, including

noise monitoring, audiometric testing, hearing protection, training, and recordkeeping.3 Additional

guidelines for an effective hearing conservation program are contained in a NIOSH technical report.14

2. Some of the highest noise exposures experienced by the PBF fire fighters were observed during

emergency responses. The use of hearing protection devices (HPDs) during this activity will greatly

reduce fire fighters' noise exposures. A large number of alternative HPDs are available on the market. 

Ear plugs and ear muffs, the same types as worn in industry, have been successfully used in fire

departments. However, because of the time constraints associated with an emergency response run, it

is more practical to use ear muffs because of their relative ease in fitting in a short time period. 

Communication systems with speakers placed in ear muffs and noise-blanking microphones have been

developed to connect with fire department radio systems. The NIOSH investigator has seen these in

use in several fire departments, including Sacramento, California, and Phoenix, Arizona, as well as in

air ambulance services. Recently, an active noise-controlling ear muff that creates a destructive noise

to reduce the wearer's exposure has been introduced in the U.S. and marketed as a way to lower

noise in emergency medical service vehicles. This latter device is relatively new and expensive.

3. The audiometric data from the hearing conservation program should be analyzed by methods

proposed by an American National Standards Institute (ANSI) working group concerned with

audiometric database analyses.15 The analysis techniques have been evaluated by hearing

conservation investigators who have reported success in their use.16-19 The techniques allow a hearing

conservationist to identify groups of employees that may need further help in preventing hearing losses

through the analysis of group audiometric data, rather than each individual's hearing tests, which are

not as sensitive an indicator of a hearing conservation program problem. Small changes over a short

period of time can be investigated in order to ascertain, for example, if different kinds of hearing

protection are appropriate or if fire fighters assigned to a particular fire vehicle or fire station are

exhibiting hearing losses that are changing more rapidly than other members of the department. The

use of these techniques may allow for intervention into the problem quicker than if individual hearing

tests are evaluated in a routine doctor/patient relationship and consultation.

4. The mechanical siren in use by the PBF generates the warning signal by rapidly turning a wheel inside

of the siren's housing. The circular housing has several slots cut in the perimeter to allow the warning

sound to escape. When this type of siren is placed on the left fender or left side of the front bumper of

the fire vehicle, much of the sound energy is directed back to the driver's side window. A recently
Page 13 - Health Hazard Evaluation Report No. 88-0290

reported study by the Liberty Mutual Insurance Group describes an engineering control that

incorporated a shroud installed on the siren that redirects the sound in a forward direction. The siren

was also moved to the center of the front bumper. The report states that a 70% reduction in the sound

pressure levels were afforded as a result of the change.20 The PBF should consider applying this type

of engineering control to their mechanical sirens. 

5. The spectral data reported for the vehicles in use by the PBF showed that fire fighters riding the

Thibault truck had less noise exposure from siren noise than those in the other vehicles which used

electronic sirens as the warning device. The speaker for the siren on the Thibault truck was located

under the front bumper. Most of the speakers on other fire vehicles, including Brockway engines and

squad and battalion chief cars, were mounted on light bars located on the top of the cab. Alternate

locations for the speakers on these latter vehicles in the front grille or under the front bumper should be

investigated by the vehicle maintenance department.

6. Engine noise was a major source of exposure to the fire fighters during emergency response runs. It

was especially evident in vehicles that were configured with the engine located behind the cab and

between the jumpseat riding positions. The use of a metalicized blanket over the engine cowling has

been observed by the NIOSH investigator in the Anaheim, California Fire Department to reduce the

noise that is directed to fire fighters riding in the jumpseats. It also helps to reduce the heat generated

by the engine, which was mentioned as a concern by fire fighters during periods of hot weather. This

kind of engineering control needs to be investigated with the manufacturers of the vehicles to make

sure that heat build-up in the engine does not become a problem. Additional venting of the air around

the engine, which will also redirect the noise output, can be pursued by the vehicle maintenance

department.

7. The use of noise absorption materials on hard surfaces of the fire vehicles will reduce reverberant noise

exposures to the personnel on the vehicles. The older vehicles still used by the PBF can have this kind

of material added to the hard surfaces. Newer vehicles may already use this kind of noise control. In

either case, a maintenance program that monitors the integrity of the sound absorption materials needs

to be implemented. These controls will deteriorate over time in the harsh environments that the fire

vehicles encounter. They need to be replaced when they become torn or brittle.

8. Noise controls in vehicles that the manufacturer provides need to be included in future vehicle

purchases. Several makers of pumpers and trucks advertise noise control as one of their features. 

Maximum noise levels for specific operations need to be spelled out in the performance specifications

for the purchase of new equipment. The NFPA guidelines are appropriate specifications to which the

department can refer manufacturers for maximum noise levels.12
Page 14 - Health Hazard Evaluation Report No. 88-0290

X. REFERENCES

1. 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.

2. Ward WD, Fleer RE, Glorig A [1961]. Characteristics of hearing loss produced by gunfire and by

steady noise. Journal of Auditory Research 1:325-356.

3. Code of Federal Regulations [1992]. OSHA. 29 CFR 1910.95. Washington, DC: U.S.

Government Printing Office, Federal Register.

4. 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.

5. ACGIH [1992]. Threshold limit values and biological exposure indices for 1992-93. Cincinnati,

OH: American Conference of Governmental Industrial Hygienists.

6. ANSI [1970]. Specifications for audiometers (S3.6). New York, New York: American National

Standards Institute, Inc.

7. AAO - HNS [May, 1983]. Otological referral criteria for occupational hearing conservation

programs. Washington, D.C.: American Academy of Otolaryngology - Head and Neck Surgery

Board of Directors.

8. Kryter KD [1970]. The effects of noise on man. New York, New York: Academic Press.

9. Eagles EL, Hardy WG, Catlin FI [1968]. Human communication: The public health aspects of

hearing, language, and speech disorders (NINDB Monograph #7). Washington, D.C.: 

Government Printing Office. (USPHS publication no. 1745).

10. Tubbs RL [1990]. Health hazard evaluation: Memphis Fire Department, Memphis, Tennessee. 

HETA Report No. 86-138-2017. National Institute for Occupational Safety and Health,

Cincinnati, Ohio.

11. Tubbs RL, Flesch JP [1982]. Health hazard evaluation: Newburgh Fire Department. HHE

Report No. 8l-059-1045. National Institute for Occupational Safety and Health, Cincinnati, Ohio.

12. NFPA [1987]. Standard on Fire Department Occupational Safety and Health Program (NFPA

1500). Quincy, Massachusetts: National Fire Protection Association.

13. Tubbs RL, Melius J, Anderson KE [1988]. Health hazard evaluation: International Association of

Fire Fighters, Cincinnati, Ohio. HETA Report No. 84-454-1890. National Institute for

Occupational Safety and Health, Cincinnati, Ohio.
Page 15 - Health Hazard Evaluation Report No. 88-0290

14. NIOSH [1990]. A practical guide to effective hearing conservation programs in the workplace. 

Cincinnati, Ohio: National Institute for Occupational Safety and Health. (DHHS (NIOSH)

publication no. 90-120).

15. ANSI [1991]. Draft American National Standard. Evaluating the effectiveness of hearing

conservation programs (S12.13-1991). New York, New York: American National Standards

Institute, Inc.

16. Melnick W [1984]. Evaluation of industrial hearing conservation programs: A review and analysis. 

American Industrial Hygiene Association Journal 45:459-467.

17. Royster JD, Royster LH [1986]. Audiometric data base analysis. Chapter 9. In: Berger EH,

Ward WD, Morrill JC, Royster LH, eds. Noise & hearing conservation manual. 4th ed. Akron,

OH: American Industrial Hygiene Association, pp 293-317.

18. Royster JD, Royster LH [1990]. Hearing conservation programs: Practical guidelines for success. 

Boca Raton, FL: Lewis Publishers, Inc.

19. Royster LH, Royster JD [1988]. Getting started in audiometric data base analysis. Seminars in

Hearing 9:325-337.

20. Heany M [1994]. Effect of sound focusing device on reducing fire engine siren noise. Unpublished

poster presented at 1994 Industrial Hygiene Conference and Exposition, Anaheim, CA, May 23,

1994.
Page 16 - Health Hazard Evaluation Report No. 88-0290

XI. INVESTIGATORS AND ACKNOWLEDGEMENTS

Investigator: Randy L. Tubbs, Ph.D.

Psychoacoustician

Industrial Hygiene Section

Hazard Evaluations and Technical

Assistance Branch

Field Support:

 Industrial Hygiene - Gregory A. Burr, CIH

Industrial Hygienist

Mary Ann Newman, Ph.D., CIH

Industrial Hygienist

Teresa A. Seitz, CIH

Industrial Hygienist

Richard L. Stephenson, CIH

Industrial Hygienist

 Audiometry - Kathleen F. Conway

Audiometric Technician

Lynette K. Hartle

Audiometric Technician

Patricia E. McKinzie

Audiometric Technician

Nancy L. Zumwalde

Audiometric Technician

Report Typed By: Kate L. Marlow

Office Automation Assistant

Industrial Hygiene Section

Originating Office: Hazard Evaluations and Technical

Assistance Branch

Division of Surveillance, Hazard

Evaluations, and Field Studies
Page 17 - Health Hazard Evaluation Report No. 88-0290

XII. DISTRIBUTION AND AVAILABILITY

Copies of this report may be freely reproduced and are not copyrighted. Single copies of this report will be

available for a period of 90 days from the date of this report from the NIOSH Publications Office, 4676

Columbia Parkway, Cincinnati, Ohio 45226. To expedite your request, include a self-addressed mailing

label or envelope along with your written request. After this time, copies may be purchased from the

National Technical Information Service (NTIS), 5285 Port Royal Road, Springfield, Virginia 22161. 

Information regarding the NTIS stock number may be obtained from the NIOSH Publications Office in

Cincinnati. 

Copies of this report have been sent to:

1. Fire Chief, Pittsburgh Bureau of Fire

2. Local #1, International Association of Fire Fighters

3. Department of Health & Safety, International

 Association of Fire Fighters

4. OSHA, Region III

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. 
TABLE 1 (Page 1 of 3)

Average Noise Doses, Maximum Levels, and Number of Responses

for the Surveyed Engines

Pittsburgh Bureau of Fire

Pittsburgh, Pennsylvania

HETA 88-290

Sept. & Oct., 1988

Engine DOSE

 No. Type Date Responses Maximum 8-Hr 10-Hr 14-Hr

 #1 Grumman 9/12 1 (0) 96 17.0 % 21.0 % 29.7 %

 9/13 0 (0) 97 10.3 % 13.0 % 18.0 %

 #4 Pierce 9/12 Training 111 79.0 % 99.0 % 138.0 %

 9/13 Training 105 34.0 % 42.7 % 60.3 %

 #5 Mack 9/12 4 (3) 102 23.3 % 29.3 % 41.0 %

 9/13 4 (1) 110 24.5 % 30.5 % 43.0 %

 #6 Pierce 9/14 2 (1) 116 29.5 % 36.5 % 51.5 %

 9/15 1 (1) 104 19.3 % 24.0 % 33.7 %

 #7 Brockway 9/14 0 (0) 115 40.0 % 50.0 % 69.5 %

 9/15 1 (0) 104 24.3 % 30.3 % 42.7 %

 #8 Pierce 9/14 4 (4) 109 34.5 % 43.0 % 60.5 %

 9/15 4 (3) 120 51.7 % 64.7 % 90.0 %

#11 Brockway 10/05 4 (3) 110 63.3 % 79.3 % 111.0 %

10/06 2 (2) 98 13.5 % 17.0 % 23.5 %

#12 Mack 10/03 2 (1) 97 25.5 % 32.0 % 44.5 %

10/04 0 (0) 108 23.3 % 29.0 % 40.3 %
TABLE 1 (Page 2 of 3)

Average Noise Doses, Maximum Levels, and Number of Responses

for the Surveyed Engines

Pittsburgh Bureau of Fire

Pittsburgh, Pennsylvania

HETA 88-290

Sept. & Oct., 1988

Engine DOSE

 No. Type Date Responses Maximum 8-Hr 10-Hr 14-Hr

#13 Mack 10/03 3 (3) 108 20.7 % 25.3 % 35.7 %

10/04 1 (0) 95 18.7 % 23.3 % 32.7 %

#14 Pierce 10/03 4 (3) 104 24.0 % 30.3 % 42.0 %

10/04 3 (1) 101 23.0 % 28.7 % 40.7 %

#15 Brockway 10/05 2 (2) 105 16.3 % 20.3 % 28.3 %

10/06 Training 92 6.7 % 8.3 % 11.7 %

#18 Pierce 10/05 2 (2) 109 24.5 % 30.5 % 43.0 %

10/06 1 (0) 101 17.5 % 22.0 % 31.0 %

#23 Pierce 9/16 1 (0) 104 35.0 % 43.5 % 61.0 %

 9/17 1 (0) 100 18.0 % 23.0 % 32.0 %

#24 Mack 10/07 2 (2) 108 23.5 % 29.5 % 41.0 %

10/08 2 (1) 96 24.0 % 30.5 % 42.5 %

#26 Grumman 9/16 1 (0) 98 15.5 % 19.0 % 27.0 %

 9/17 0 (0) 90 9.3 % 12.0 % 16.3 %

#28 Grumman 9/16 4 (2) 95 10.0 % 13.0 % 18.0 %

 9/17 3 (2) 105 25.7 % 32.3 % 45.0 %
TABLE 1 (Page 3 of 3)

Average Noise Doses, Maximum Levels, and Number of Responses

for the Surveyed Engines

Pittsburgh Bureau of Fire

Pittsburgh, Pennsylvania

HETA 88-290

Sept. & Oct., 1988

Engine DOSE

 No. Type Date Responses Maximum 8-Hr 10-Hr 14-Hr

#33 Pierce 10/07 7 (6) 111 87.0 % 108.7 % 152.3 %

10/08 0 (0) 105 37.0 % 46.0 % 64.5 %

#38 Grumman 10/07 0 (0) 95 17.0 % 21.3 % 29.6 %

10/08 1 (0) 106 16.3 % 20.3 % 28.3 %

Note: Responses represents the number of occurrences where the vehicle left the station. Those which were emergency responses are

enclosed in parentheses.

Maximum is the highest one minute average recorded for any one fire fighter assigned to a vehicle.

Dose is the percentage of a daily allowable noise exposure according to OSHA regulation. A dose of 100 % is the maximum 

allowed for a day. The different hour categories are for the different work schedules of the Pittsburgh Bureau of Fire.
TABLE 2 (Page 1 of 2)

Average Noise Doses, Maximum Levels, and Number of Responses

for the Surveyed Trucks

Pittsburgh Bureau of Fire

Pittsburgh, Pennsylvania

HETA 88-290

Sept. & Oct., 1988

Truck DOSE

 No. Type Date Responses Maximum 8-Hr 10-Hr 14-Hr

 #1 Pierce 9/12 3 (0) 100 27.5 % 34.5 % 48.0 %

 9/13 3 (0) 99 30.0 % 37.3 % 52.3 %

 #4 Pierce 9/12 Training 105 40.5 % 50.5 % 71.0 %

 9/13 Training 104 38.0 % 47.5 % 66.0 %

 #5 Seagrave 9/12 3 (2) 108 24.7 % 30.7 % 42.7 %

 9/13 4 (1) 105 22.0 % 27.7 % 38.7 %

 #6 Am/LaFrance 9/14 4 (1) 107 19.7 % 24.0 % 34.0 %

 9/15 1 (1) 105 10.7 % 13.3 % 19.3 %

 #7 Pierce 9/14 0 (0) 107 39.0 % 49.0 % 68.0 %

 9/15 1 (0) 109 36.0 % 44.5 % 62.5 %

 #8 Am/LaFrance 9/14 4 (4) 105 41.0 % 51.0 % 72.0 %

 9/15 1 (1) 101 20.5 % 25.0 % 35.5 %

#13 Am/LaFrance 10/03 0 (0) 100 21.5 % 26.5 % 37.0 %

10/04 2 (1) 111 33.5 % 41.5 % 58.5 %

#14 Pierce 10/03 3 (3) 100 17.5 % 22.0 % 30.5 %

10/04 0 (0) 91 10.5 % 12.5 % 18.0 %
TABLE 2 (Page 2 of 2)

Average Noise Doses, Maximum Levels, and Number of Responses

for the Surveyed Trucks

Pittsburgh Bureau of Fire

Pittsburgh, Pennsylvania

HETA 88-290

Sept. & Oct., 1988

Truck DOSE

 No. Type Date Responses Maximum 8-Hr 10-Hr 14-Hr

#15 Pierce 10/05 2 (1) 104 19.0 % 24.0 % 33.5 %

10/06 Training 99 9.5 % 12.0 % 17.0 %

#18 Seagrave 10/05 1 (1) 104 23.0 % 29.0 % 40.5 %

10/06 1 (0) 94 15.5 % 19.5 % 27.5 %

#23 Thibault 9/16 2 (0) 99 38.5 % 47.5 % 67.0 %

 9/17 2 (1) 106 33.7 % 41.7 % 58.3 %

#24 Seagrave 10/07 0 (0) 93 16.0 % 20.0 % 28.0 %

10/08 1 (0) 103 18.0 % 22.5 % 31.5 %

#26 Thibault 9/16 1 (0) 94 19.0 % 24.5 % 34.0 %

 9/17 0 (0) 86 8.0 % 10.0 % 14.0 %

#38 Thibault 10/07 1 (0) 110 11.0 % 14.0 % 19.5 %

10/08 1 (0) 94 6.0 % 7.5 % 10.5 %

Note: Responses represents the number of occurrences where the vehicle left the station. Those which were emergency responses are enclosed in

parentheses.

Maximum is the highest one minute average recorded for any one fire fighter assigned to a vehicle.

Dose is the percentage of a daily allowable noise exposure according to OSHA regulation. A dose of 100 % is the maximum allowed for a day. The

different hour categories are for the different work schedules of the Pittsburgh Bureau of Fire.
TABLE 3

Average Noise Doses, Maximum Levels, and Number of Responses

for the Surveyed Squads

Pittsburgh Bureau of Fire

Pittsburgh, Pennsylvania

HETA 88-290

Sept. & Oct., 1988

Squad DOSE

 No. Date Responses Maximum 8-Hr 10-Hr 14-Hr

#11 10/05 4 (4) 101 26.5 % 33.0 % 46.5 %

10/06 4 (1) 98 18.0 % 22.5 % 31.5 %

#12 10/03 4 (2) 101 17.3 % 21.7 % 30.0 %

10/04 3 (1) 93 9.0 % 11.0 % 16.0 %

#24 10/07 2 (1) 92 25.0 % 31.0 % 43.0 %

10/08 1 (0) 92 17.0 % 22.0 % 30.0 %

#28 9/16 0 (0) 88 12.0 % 15.0 % 21.0 %

 9/17 2 (0) 108 20.3 % 25.7 % 35.7 %

#33 10/07 9 (5) 102 42.0 % 52.0 % 73.0 %

10/08 2 (1) 100 38.5 % 48.0 % 67.0 %

Note: Responses represents the number of occurrences where the vehicle left the station. Those which were emergency responses are

enclosed in parentheses.

Maximum is the highest one minute average recorded for any one fire fighter assigned to a vehicle.

Dose is the percentage of a daily allowable noise exposure according to OSHA regulation. A dose of 100 % is the maximum allowed for a

day. The different hour categories are for the different work schedules of the Pittsburgh Bureau of Fire.
TABLE 4 (Page 1 of 3)

Median dB(A) Sound Levels for the Fire Apparatus

Pittsburgh Bureau of Fire

Pittsburgh, Pennsylvania

HETA 88-0290

Manufacturer Vehicle Type Seat Location Warning Signals Median dB(A) Levels

Pierce Engine Cab yes 99.8

Engine Cab no 88.1

Engine Jumpseat yes 104.0 

Engine Jumpseat no 100.5 

Rear Mount

 Truck

Cab yes 100.0 

Rear Mount

 Truck

Cab no 89.6

Rear Mount

 Truck

Jumpseat yes 105.2 

Rear Mount

 Truck

Jumpseat no 101.9 

Tiller Truck Cab yes 101.8 

Tiller Truck Cab no 91.3

Tiller Truck Jumpseat yes 105.9 

Tiller Truck Jumpseat no 100.7 

Tiller Truck Tiller yes 93.4

Tiller Truck Tiller no 83.4

Lance (Foam) Cab yes 96.2

Lance (Foam) Cab no 89.2

Lance (Foam) Jumpseat yes 89.8

Lance (Foam) Jumpseat no 85.7
TABLE 4 (Page 2 of 3)

Median dB(A) Sound Levels for the Fire Apparatus

Pittsburgh Bureau of Fire

Pittsburgh, Pennsylvania

HETA 88-0290

Manufacturer Vehicle Type Seat Location Warning Signals Median dB(A) Levels

Seagrave Rear Mount 

 Truck

Cab yes 108.2 

Rear Mount

 Truck

Cab no 91.1

Rear Mount

 Truck

Jumpseat yes 109.2 

Rear Mount

 Truck

Jumpseat no 99.2

Front Mount

 Truck

Cab yes 104.0 

Front Mount

 Truck

Jumpseat yes 101.9 

Tiller Truck Cab yes 105.9 

Tiller Truck Cab no 89.4

Tiller Truck Jumpseat yes 119.4 

Tiller Truck Jumpseat no 101.0 

Brockway Engine Cab yes 106.1 

Engine Cab no 87.9

Engine Tailboard yes 103.4 

Engine Tailboard no 82.7

Grumman Engine Cab yes 106.0 

Engine Cab no 83.7

Engine Tailboard yes 103.2 

Engine Tailboard no 79.8
TABLE 4 (Page 3 of 3)

Median dB(A) Sound Levels for the Fire Apparatus

Pittsburgh Bureau of Fire

Pittsburgh, Pennsylvania

HETA 88-0290

Manufacturer Vehicle Type Seat Location Warning Signals Median dB(A) Levels

Mack Engine Cab yes 113.2 

Engine Cab no 84.4

Engine Tailboard yes 98.9

Engine Tailboard no 85.0

Thibault Rear Mount

 Truck

Cab yes 99.4

Rear Mount

 Truck

Cab no 85.9

Rear Mount

 Truck

Jumpseat yes 102.1 

Rear Mount

 Truck

Jumpseat no 93.2

Squads Front Seat yes 101.4 

Back Seat yes 97.8
APPENDIX 1

Voluntary Consent Form and Job History Questionnaire
DEPARTMENT OF HEALTH AND HUMAN SERVICES

PUBLIC HEALTH SERVICE

CENTERS FOR DISEASE CONTROL AND PREVENTION

NATIONAL INSTITUTE FOR OCCUPATIONAL SAFETY AND HEALTH

CONSENT TO PARTICIPATE IN A MEDICAL STUDY

PROJECT TITLE:

HETA #:

PURPOSE:

I, , agree to participate in this study. 

 (Please Print)

The procedures have been discussed with me, and I have been given a copy of this consent form. I understand that:

1. I will be asked questions about work history, noisy activities, and medical symptoms. I will also be given a hearing

test which checks my ability to hear different sounding tones.

2. In the unlikely event of physical injury resulting from participation in this study, NIOSH will only be able to provide

emergency treatment. Any compensation for medical care or lost wages will have to be obtained under the Federal

Tort Claims Act (28 USC 1346 (b)).

3. Except as stated under provisions of the Privacy Act (PL 93-579), no information that I furnish for this study can be

disclosed in a manner which will identify me unless I give written permission.

4. My participation is voluntary, and I may withdraw from the study at any time without prejudice to myself.

5. Any questions I have regarding this study should be directed to the project officer, Dr. Randy L. Tubbs, Hazard

Evaluations and Technical Assistance Branch, Mail Stop R-11, 4676 Columbia Parkway, Cincinnati, Ohio 45226,

telephone (513) 841-4374.

PARTICIPANT'S SIGNATURE DATE 

MAILING ADDRESS: 

(Please Print)

 

PROJECT OFFICER'S SIGNATURE DATE 
PITTSBURGH BUREAU OF FIRE

HETA 88-290

FIRE FIGHTER'S SERVICE QUESTIONNAIRE

(leave blank) ID# 

1. NAME: 

2. ADDRESS: (Street)

 

(City) (State) (Zip) 

3. AGE: DATE OF BIRTH: 

(Years) (Mon) (Day) (Yr)

4. SEX: 

5. HOW LONG HAVE YOU BEEN A FIRE FIGHTER?: 

CURRENT ASSIGNMENT

6. STATION ASSIGNED: 7. HOW LONG: 

8. JOB CLASSIFICATION: 

OTHER FIRE DEPARTMENT ASSIGNMENTS (PBF)

9. STATION ASSIGNED: 10. HOW LONG: 

11. JOB CLASSIFICATION: 

12. STATION ASSIGNED: 13. HOW LONG: 

14. JOB CLASSIFICATION: 

15. STATION ASSIGNED: 16. HOW LONG: 

17. JOB CLASSIFICATION: 

 Note: If you have had additional assignments, please list on back of this page.
18. COMPANY NAME: 19. HOW LONG: 

20. JOB CLASSIFICATION: 

21. WHEN DID YOU BEGIN THIS OCCUPATION: 

22. HOURS PER (WEEK) (MONTH) (YEAR): 

23. COMPANY NAME: 24. HOW LONG: 

25. JOB CLASSIFICATION: 

26. WHEN DID YOU BEGIN THIS OCCUPATION: 

27. HOURS PER (WEEK) (MONTH) (YEAR): 

 Note: If you have had additional jobs, please list on back of this page.

MILITARY EXPERIENCE

28. YEARS AND MONTHS OF ACTIVE DUTY: 

(Years) (Months)

29. BRANCH OF SERVICE: 30. TIME IN COMBAT: 

31. MILITARY JOBS, ASSIGNMENTS, OR DUTIES:

A. 

B. 

C. 

32. DID YOU FIRE WEAPONS? 

 (YES) (NO)

33. DID YOU FIRE WEAPONS FOR MORE THAN 100 DAYS? 

 (YES) (NO)
HOBBIES AND ACTIVITIES

34. DO YOU ENGAGE IN ANY OF THE FOLLOWING?

Times per...

Activity Yes No day week month year

A. Hunting 

B. Shooting 

C. Motorcycle 

D. Drag Race 

E. Chain Saw 

F. Farm Tractor 

G. Woodworking 

H. Loud Music 

I. Other: __________ 

MEDICAL HISTORY

35. HAVE YOU EVER HAD TROUBLE WITH YOUR EARS? 

(Yes) (No)

IF YES, DESCRIBE:

 

36. HAVE YOU BEEN SEEN BY A PHYSICIAN ABOUT YOUR EARS?

 

(Yes) (No)

37. HAVE YOU EVER NOTICED ANY CHANGES IN YOUR HEARING?

 

(Yes) (No)

38. HAVE YOU EVER HAD ANY OF THE FOLLOWING: HEARING

YES NO CHANGE?

a. Mumps 

b. Measles 

c. Allergies 

d. High Blood Pressure 

e. Mycin Drugs (antibiotics) 

f. Quinine 

g. Severe Blow to Head 

h. Tinnitus ("ringing in ears") 

i. Excessive Ear Wax Buildup