NIOSH HEALTH HAZARD EVALUATION REPORT 

HETA #2006-0222-3037 

Society for the Prevention of Cruelty to Animals 

Cincinnati, Ohio 

February 2007 

DEPARTMENT OF HEALTH AND HUMAN SERVICES 

Centers for Disease Control and Prevention 

National Institute for Occupational Safety and Health
ii 

PREFACE

The Hazard Evaluation and Technical Assistance Branch (HETAB) of the National Institute for 

Occupational Safety and Health (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 (OSHA) 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 employers 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. 

HETAB 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 NIOSH. 

ACKNOWLEDGMENTS AND AVAILABILITY OF REPORT

This report was prepared by Chandran Achutan and Randy L. Tubbs of HETAB, Division of 

Surveillance, Hazard Evaluations and Field Studies (DSHEFS). Field assistance was provided by Donnie 

Booher, Judi Eisenberg, and Charles Mueller. Desktop publishing was performed by Robin Smith. 

Editorial assistance was provided by Ellen Galloway. 

Copies of this report have been sent to employee and management representatives at the Society for the 

Prevention of Cruelty to Animals-Cincinnati and the OSHA Regional Office. This report is not 

copyrighted and may be freely reproduced. The report may be viewed and printed from the following 

internet address: http://www.cdc.gov/niosh/hhe. Copies may be purchased from the National Technical 

Information Service (NTIS) at 5825 Port Royal Road, Springfield, Virginia 22161. 

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 

Highlights of Health Hazard Evaluation 

Highlights of the NIOSH Health Hazard Evaluation

In April 2006, NIOSH investigators received a management request from the Cincinnati branch 

of the Society for the Prevention of Cruelty to Animals (SPCA-Cincinnati) to evaluate noise 

exposures and potential hearing loss among kennel workers at SPCA-Cincinnati. Between 

September and October 2006, noise assessments and hearing tests were conducted on SPCACincinnati employees. 

What NIOSH Did

 We measured personal noise exposures 

for kennel workers. 

 We tested hearing levels of kennel 

workers, maintenance workers, animal 

rescue workers, office workers, and 

veterinary staff. 

What NIOSH Found

 Noise levels exceeded the NIOSH 

recommended exposure limit on 

seventeen occasions and exceeded the 

Occupational Safety and Health 

Administration limit on four occasions. 

 Nine of 19 employees including five 

kennel workers showed hearing loss. 

What SPCA-Cincinnati Managers 

Can Do

 Enroll employees in a hearing loss 

prevention program. 

 Require the use of ear plugs or ear muffs 

in the kennel area. 

 Maintain ear muffs by making sure they 

are clean and replacing the cushions 

every 6 months or sooner if necessary. 

 Post signs to show areas with loud noise, 

and have hearing protectors available to 

employees entering these areas. 

 Cover the floors and ceilings with sound 

absorbing materials that are easy to clean 

and disinfect. 

What SPCA-Cincinnati Employees 

Can Do 

 Wear hearing protectors when working 

in the kennel areas. 

What To Do For More Information:

We encourage you to read the full report. If you 

would like a copy, either ask your health and 

safety representative to make you a copy or call 

1-513-841-4252 and ask for 

HETA Report #2006-0222-3037
iv 

Health Hazard Evaluation Report 2006-0222-3037 

Society for the Prevention of Cruelty to Animals 

Cincinnati, Ohio 

February 2007 

Chandran Achutan, Ph.D. 

Randy L. Tubbs, Ph.D. 

SUMMARY

On April 25, 2006, the National Institute for Occupational Safety and Health (NIOSH) received a request 

for a health hazard evaluation (HHE) from the Society for the Prevention of Cruelty to AnimalsCincinnati (SPCA-Cincinnati) in Hamilton County, Ohio. The HHE request asked NIOSH to assess the 

noise levels experienced by kennel workers from barking dogs. On September 28 and 29, 2006, NIOSH 

investigators measured noise exposure levels for kennel workers. On October 11 and 16, 2006, NIOSH 

investigators returned to the facility to conduct hearing tests on employees working in the kennel area. 

Other employees including maintenance workers, veterinary technicians, animal rescue workers, and 

front-office personnel who frequent the kennel area were also invited to take a hearing test. 

Twelve employees contributed 19 personal noise measures over the 2-day survey. Seventeen of the 19 

personal noise measures exceeded the daily allowable dose of 100% as calculated by the NIOSH 

recommended exposure limit criterion. In addition, 11 measures also exceeded the Occupational Safety 

and Health Administration (OSHA) action level and four measures exceeded the OSHA permissible 

exposure limit. Nine workers showed some degree of hearing loss (> 25 decibel hearing loss) at one or 

more test frequencies in one or both ears on the NIOSH-administered audiogram. Five workers with 

normal hearing showed notches (hearing levels worsen over test frequencies before improving in the 

highest frequencies, forming a “notch” configuration) in one or both ears at 4000 and 6000 Hertz perhaps 

indicating early signs of hearing loss. There were 21 notches in one or both ears of the 19 employees. 

Kennel workers at SPCA-Cincinnati are exposed to excessive noise levels. Some kennel 

workers and others who frequent the kennel area have some hearing loss but it is not 

possible to determine whether this is related to noise exposures in the kennel. 

Recommendations are provided to reduce noise exposures and prevent further hearing 

loss. These recommendations include establishing a hearing loss prevention program, 

installing sound-absorbing materials in kennels, and wearing hearing protection devices 

when entering the kennel area. 

Keywords: NAICS 813312 (Environment, Conservation and Wildlife Organizations), noise, dose, 

hearing loss, dog, notch, audiometric testing 
Table of Contents 

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

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

Highlights of Health Hazard Evaluation .................................................................................................iii

Summary.....................................................................................................................................................iv

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

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

Noise Exposures to Domestic Animal Handlers ...................................................................................1

SPCA-Cincinnati.....................................................................................................................................1

Methods........................................................................................................................................................2

Noise Assessment.....................................................................................................................................2

Hearing Loss Assessment .......................................................................................................................2

Evaluation Criteria .....................................................................................................................................2

Results and Discussion................................................................................................................................4

Conclusions..................................................................................................................................................5

Recommendations.......................................................................................................................................6

References....................................................................................................................................................6

Tables ...........................................................................................................................................................8

Figure .........................................................................................................................................................10
Health Hazard Evaluation Report No. 2006-0222-3037 Page 1 

INTRODUCTION

On April 25, 2006, the National Institute for 

Occupational Safety and Health (NIOSH) 

received a management request for a health 

hazard evaluation (HHE) from the Society for 

the Prevention of Cruelty to Animals-Cincinnati 

(SPCA-Cincinnati) in Hamilton County, Ohio. 

The HHE request asked NIOSH to assess 

employee exposure to noise from barking dogs. 

An informal meeting was held between the 

principal NIOSH investigator, management, and 

an employee representative to explain the HHE 

process and to discuss the logistics of the 

evaluation. On September 28 and 29, 2006, 

NIOSH investigators measured noise exposure 

levels for kennel workers. On October 11 and 

16, 2006, NIOSH investigators returned to the 

facility to conduct hearing tests for employees 

working in the kennel area. Employees who 

frequent the kennel area were also invited to 

take a hearing test. 

BACKGROUND

Noise Exposures to Domestic 

Animal Handlers 

Veterinary hospital workers, animal shelter 

employees, workers at facilities that board 

animals, and police officers with canine partners 

are potentially exposed to excessive 

occupational noise levels from barking dogs. 

However, few studies have examined noise 

exposures and the potential for hearing loss 

among these workers. One study measured noise 

levels as high as 108 decibels on an A-weighted 

scale (dBA) in veterinary establishments.1

Another study in an outdoor animal shelter 

showed noise exposures in excess of the NIOSH 

recommended exposure limit (REL) for 

occupational noise.2

 This evaluation was 

conducted in the aftermath of Hurricane Katrina 

in St. Bernard Parish, Louisiana, and is not 

representative of typical veterinary staff noise 

exposure. Two studies examined noise 

exposures and hearing loss among canine police 

officers.3,4 Both studies found that police 

officers were exposed to excessive noise from 

canines, and some officers had hearing loss. The 

design of these studies did not enable 

investigators to determine whether observed 

hearing loss was associated with occupational 

noise exposures. 

SPCA-Cincinnati 

The Cincinnati branch of the SPCA was formed 

in 1873 as a nonprofit organization dedicated to 

the welfare of animals in Hamilton County, 

Ohio. SPCA-Cincinnati finds homes for cats and 

dogs, rescues animals, provides veterinary 

services, and spays and neuters animals. The 

occupancy levels at the facility are usually at 

capacity. 

Animals brought into SPCA-Cincinnati are 

processed in the intake area. Once processed, 

most animals are taken to the veterinary clinic 

for observation. Subsequently the animals are 

taken to the kennel area. The main kennels for 

dogs are adjacent to the intake area. There are 

three “runs” (or aisles); each run has 

approximately 40 cages evenly divided on each 

side of the run. Dogs that are put up for adoption 

are kept in Run 1. Usually, there is only one dog 

in each cage. Stray dogs are kept in Run 2. 

There may be up to five dogs per cage in Run 2. 

Aggressive dogs and dogs that are evidence in 

court proceedings are quarantined in Run 3. 

Across from the kennels are rooms that house 

puppies, kittens, and cats. In a separate wing of 

the facility called the auditorium is another 

kennel for dog adoptions. There are 40 cages in 

this area. Adjacent to the dog kennels is a 

veterinary clinic that is isolated from the 

auditorium. The clinic also has animal cages 

where sick animals are kept for observation. The 

veterinary clinic is staffed by a veterinarian and 

veterinary technicians. They are assisted by 

kennel staff who help restrain animals, clean 

animal cages, transport animals to the clinic and 

return them to the cages, and perform routine 

housekeeping duties. 

Kennel workers are responsible for keeping the 

kennels clean at all times, feeding the animals, 

cleaning bathrooms, and taking animals to the 

front office for adoptions. Every morning, the 

kennel manager provides a list outlining the duty 
Page 2 Health Hazard Evaluation Report No. 2006-0222-3037 

stations and tasks to be completed by each 

employee. Approximately 10 employees work in 

the kennel area every day. They start work 

between 7:00 a.m. and 9:30 a.m., and leave work 

between 4:30 p.m. and closing (around 7:00 

p.m.). They are given an hour for lunch; 

however most employees work through their 

lunch break. One employee comes in at 1:00 

p.m. and stays until closing. This employee gets 

a 15-minute break at around 4:30 p.m. A 

veterinary technician, office workers, animal 

rescue officers, and a maintenance worker 

frequent the kennel as part of their daily tasks. 

METHODS

Noise Assessment 

On September 28–29, 2006, 12 kennel workers 

contributed 19 full-shift, personal noise 

measures. Quest® Technologies (Oconomowoc, 

Wisconsin) Model Q-300 Noise Dosimeters 

were worn by the kennel workers while they 

performed their daily activities. The noise 

dosimeters were attached to the wearer’s belt 

and a small remote microphone was fastened to 

the wearer’s shirt at a point midway between the 

ear and the outside of the shoulder. A 

windscreen provided by the dosimeter 

manufacturer was placed over the microphone 

during recordings. At the end of the workday, 

the dosimeter was removed and paused to stop 

data collection. The information stored in the 

dosimeters was downloaded to a personal 

computer for interpretation with QuestSuite for 

Windows® computer software. The dosimeters 

were calibrated before and after the 

measurement periods according to the 

manufacturer’s instructions. 

Hearing Loss Assessment 

All SPCA-Cincinnati kennel workers were 

eligible for the hearing tests. Workers reported 

to a NIOSH mobile test facility prior to starting 

their work shift. Informed consent was obtained 

from each participant before they completed a 

short questionnaire about work history and self 

assessment of their hearing ability. 

A Tremetrics (Eden Prairie, Minnesota) Model 

AR 901 Hearing Booth and OSCAR 7 ElectroAcoustic Ear and Octave Monitor (Eden Prairie, 

Minnesota) provided an appropriate acoustic 

environment for testing. The booth was located 

inside the mobile test facility. The area was 

controlled for conversations and other 

extraneous noises during the tests. Hearing tests 

were collected with a Tremetrics Model HT 

Wizard Audiometer that had received a routine 

calibration check within the past year. Hearing 

tests were conducted by one of the investigators 

who has current certification from the Council 

for Accreditation in Occupational Hearing 

Conservation (CAOHC). The audiometer tested 

the pure-tone frequencies of 500, 1000, 2000, 

3000, 4000, 6000, and 8000 Hertz (Hz) in the 

computerized mode in each ear, left ear first. 

Test results for each participant were interpreted 

immediately after testing and explained to the 

participant. In addition, each participant was 

sent a letter summarizing his or her results along 

with a copy of the audiometric test results. 

EVALUATION CRITERIA

The primary sources of evaluation criteria for 

noise in the workplace are: (1) the NIOSH 

RELs,5

 and (2) the U.S. Department of Labor, 

Occupational Safety and Health Administration 

(OSHA) permissible exposure limit (PEL).6

Employers are encouraged to follow the more 

protective NIOSH REL, although they are 

required to adhere to the OSHA PEL for 

compliance purposes. 

Noise-induced hearing loss (NIHL) 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.7

 While 

loss of hearing may result from a single 

exposure to a very brief impulse noise or 

explosion, such traumatic losses are rare. In 
Health Hazard Evaluation Report No. 2006-0222-3037 Page 3 

most cases, NIHL 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.8

The dBA is the preferred unit for measuring 

sound levels to assess worker noise exposures. 

The dBA 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 dBA scale is 

logarithmic, increases of 3 dBA, 10 dBA, and 20 

dBA represent a doubling, tenfold increase, and 

hundred-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)6

 specifies a 

maximum PEL of 90 dBA for a duration of 

8 hours per day. 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 dBA for no more than 4 hours, to 100 dBA 

for 2 hours, etc. Conversely, up to 16 hours 

exposure to 85 dBA is allowed by this exchange 

rate. The duration and sound level intensities can 

be combined in order to calculate a worker's 

daily noise dose according to the formula: 

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

where Cn indicates the total time of exposure at a 

specific noise level and Tn indicates the 

reference duration for that level as given in 

Table G-16a of the OSHA noise regulation. 

During any 24-hour period, a worker is allowed 

up to 100% of his daily noise dose. Doses 

greater than 100% exceed the OSHA PEL. 

The OSHA regulation has an additional action 

level (AL) of 85 dBA; an employer shall 

administer a continuing, effective hearing 

conservation program when the 8-hour timeweighted average (TWA) value exceeds the AL. 

The program must include monitoring, 

employee notification, observation, audiometric 

testing, hearing protection devices (HPDs), 

training, and record keeping. 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 dBA, feasible engineering or 

administrative controls shall be implemented to 

reduce the workers’ exposure levels. 

NIOSH, in its Criteria for a Recommended 

Standard,9

 proposes exposure criteria of 85 dBA 

as a TWA for 8 hours, 5 dB less than the OSHA 

standard. The criteria also use a more 

conservative 3 dB time/intensity trading 

relationship in calculating exposure limits. Thus, 

a worker can be exposed to 85 dBA for 8 hours, 

but to no more than 88 dBA for 4 hours or 91 

dBA for 2 hours. The NIOSH REL for a 12-hour 

exposure is 83 dBA or less. 

Audiometric evaluations of workers are 

conducted in quiet locations, preferably in a 

sound-attenuating chamber, by presenting pure 

tones of varying frequencies at threshold levels 

(i.e., the level of a sound that the person can just 

barely hear). Audiograms are displayed and 

stored as tables or charts of the hearing levels 

(HL) at specified test frequencies.10 Zero dB HL 

represents the hearing level of an average, 

young, normal hearing individual. In OSHAmandated hearing conservation programs, 

thresholds must be measured for pure-tone 

signals at the test frequencies of 500, 1000, 

2000, 3000, 4000, and 6000 Hz. Individual 
Page 4 Health Hazard Evaluation Report No. 2006-0222-3037 

employee’s annual audiograms are compared to 

their own baseline audiogram to determine the 

amount of standard threshold shift (STS) that 

occurred between the two tests. Specifically, 

OSHA states that an STS has occurred if the 

average threshold values at 2000, 3000, and 

4000 Hz have increased by 10 dB or more in 

either ear when comparing the annual audiogram 

to the baseline audiogram.6

 The NIOSH 

recommended threshold shift criterion is a 15-

dB shift at any frequency in either ear from 500–

6000 Hz measured twice in succession.9

Practically, the criterion is met by immediately 

retesting an employee who exhibits a 15-dB shift 

from baseline on an annual test. If the 15-dB 

shift persists on the second test, a confirmatory 

follow-up test should be given within 30 days of 

the initial annual examination. Both of these 

threshold shift criteria require at least two 

audiometric tests. In cases where only one 

audiogram is available, a criterion has been 

proposed for single-frequency impairment 

determinations.11 It employs a lower fence (the 

amount of hearing loss necessary before a 

hearing handicap is said to exist) of 25 dB HL. 

With this criterion, any person who has a 

hearing level of 26 dB HL or greater at any 

single frequency is classified as having some 

degree of hearing loss. The degree of loss can 

range from mild (26–40 dB HL) to profound 

(>90 dB HL). 

The audiogram profile is a plot of the hearing 

test frequencies (x-axis) versus the hearing 

threshold levels (y-axis). Hearing threshold 

levels are plotted in reverse (the highest hearing 

level up to 0 or -10 dB). For many workers, the 

audiogram profile tends to slope downward 

toward the high frequencies with an 

improvement at the audiogram’s highest 

frequencies, forming a “notch.”12 A notch in an 

individual with normal hearing may indicate the 

early onset of hearing loss. Although there is no 

universal criterion to define what constitutes a 

“notch,” several mathematical models that 

attempt to identify notches are presented in the 

scientific literature.13,14,15 The relative strength 

and weaknesses of these models have also been 

reviewed.16 For this evaluation, a notch is 

defined as the frequency where the hearing level 

is preceded by an improvement of at least 10 dB 

at the previous test frequency and followed by 

an improvement of at least 5 dB at the next. The 

notch from occupational noise exposures can 

occur between 3000 and 6000 Hz, depending on 

the frequency spectrum of the noise, and the 

anatomy of the individual’s ear.17,18 It is 

generally accepted that a notch at 4000 Hz is 

indicative of occupational hearing loss.19 Some 

researchers have argued that the notch at 6000 

Hz may not be a good marker for occupational 

hearing loss because it is widely seen in young 

adults and others with little documented 

occupational noise exposure.20 An individual 

may have notches at different frequencies in one 

or both ears.12

RESULTS AND 

DISCUSSION

Twelve kennel workers contributed 19 personal 

noise measures over 2 days. Seventeen of these 

measures exceeded the NIOSH REL. Eleven 

also exceeded the OSHA AL, and four exceeded 

the OSHA PEL. The full-shift TWA values for 

comparison with the NIOSH REL ranged from 

81.7 dBA to 96.1 dBA. The highest TWA values 

for the OSHA criteria were 93 dBA. One of the 

two employees whose personal noise exposure 

did not exceed the REL only worked for a halfday on the day of the evaluation. The other 

employee worked primarily at the veterinary 

clinic. Table 1 summarizes these results. The 

highest full-shift dose exceeded 1300% (96.1 

dBA) as calculated by the NIOSH method. This 

means that this employee exceeded his daily 

allowable dose by a factor of 13. The NIOSH 

investigators communicated the findings after 

the first day’s measurements to the employees 

and encouraged them to wear hearing protectors, 

which were available from the employer. One 

employee wore ear plugs on the second day of 

the survey; others said ear plugs were too 

cumbersome. One of the SPCA managers 

mentioned that OSHA had performed a noise 

survey at the facility a few years ago and 

stipulated that employees who work in Run 3 

(aggressive and court evidence animals) should 

wear hearing protectors. OSHA did not 
Health Hazard Evaluation Report No. 2006-0222-3037 Page 5 

recommend the use of hearing protectors for 

employees in other parts of the kennel. 

The jobs with the lowest noise exposure levels 

were done by employees assisting the veterinary 

staff and processing animals dropped off at the 

shelter. 

Hearing tests were given to 19 SPCA-Cincinnati 

employees. These included 15 kennel workers 

and four employees who often frequented the 

kennels (a maintenance worker, a veterinary 

technician, an office worker, and an animal 

rescue officer). The mean age of the 19 

employees was 32.9 years (range = 19–54). The 

mean age of the kennel workers was 28 years. 

The median hearing levels and inter-quartile 

ranges for these employees are shown in Figure 

1. The data showed considerable variability 

among individuals (as measured by the 

interquartile range). Nine of the 19 workers 

showed hearing levels at one or more 

frequencies that exceeded 25 dB HL, indicating 

hearing loss. Five of the nine were kennel 

workers. Five workers with normal hearing 

showed notches (hearing levels worsen over test 

frequencies before improving in the highest 

frequencies, forming a “notch” configuration) in 

one or both ears at 4000 and 6000 Hz perhaps 

indicating early signs of hearing loss. There 

were 21 notches in one or both ears of the 19 

employees. Table 2 shows the relationship 

between hearing test results and notch 

formation. 

Noise control strategies in dog kennels are 

complicated. Sound-absorbing materials such as 

spray-on foam and fibrous mineral wool, which 

are usually used in industry and other indoor 

settings to reduce noise exposures, are not 

appropriate in kennels because they are difficult 

to clean while maintaining dryness in order to 

avoid mold and mildew. One approach may be 

to use sound-absorbing material on surfaces that 

do not need to be cleaned routinely, such as 

ceilings. Acoustical ceiling tiles that are 

waterproof and washable can be installed to 

reduce noise.21 In addition, floors can be covered 

with rubber mats to absorb sound from the 

barking dogs and to reduce noise from feeding 

and drinking dishes hitting on hard (concrete and 

tile) surfaces. These approaches may offer some 

reduction in noise levels. Such approaches, 

however, does not eliminate the direct noise path 

from the dog to the worker. A noise survey 

should be conducted after these controls are in 

place to determine if personal noise exposures to 

workers are reduced. If there are plans for 

building a new facility or expanding the current 

facility, an acoustical engineer can assist in 

designing dog confinement areas that may 

reduce noise exposures. 

A possible administrative noise control strategy 

would be to train all kennel workers to assist at 

the veterinary clinic and the intake area, and 

rotate them on a daily basis. This strategy alone 

may not be adequate to reduce exposures below 

the REL, but could be done in conjunction with 

the use of hearing protectors. Hearing protectors, 

if worn properly all of the time, offer adequate 

protection. However, as far as possible, the 

preferred ways of controlling for noise is 

engineering, followed by administrative, and 

lastly through the use of hearing protectors. 

A noise survey should be conducted after any 

controls are in place to determine if personal 

noise exposures to workers are reduced. If there 

are plans for building a new facility or 

expanding the current facility, an acoustical 

engineer can assist in designing dog 

confinement areas that may reduce noise 

exposures. 

CONCLUSIONS

This evaluation showed that kennel workers 

with the SPCA-Cincinnati are exposed to 

hazardous noise levels. Some kennel and nonkennel workers who participated in this 

evaluation showed hearing loss. However, 

because of the small sample size, inability to 

control for other sources of noise, and the 

relative youth of the workers with respect to 

time needed to develop hearing loss, it is not 

possible to determine whether the observed 

hearing loss is related to noise exposure at the 

kennel. 
Page 6 Health Hazard Evaluation Report No. 2006-0222-3037 

RECOMMENDATIONS

Based on the observations and findings of this 

evaluation, the following recommendations are 

offered to better protect the hearing of workers 

at SPCA-Cincinnati. 

1. Establish a hearing loss prevention 

program for the kennel workers. The 

basic elements of the program should, at 

a minimum, meet the requirements for a 

hearing conservation program as 

outlined in the OSHA hearing 

conservation amendment (29 CFR 

1910.95).6

 Other sources for defining 

effective hearing conservation programs 

are also available.12,22,23 

2. Wear hearing protection devices (ear 

muffs or ear plugs) when working in the 

kennel areas. Employees should be 

trained on the proper fit, selection, and 

maintenance of hearing protectors. For 

example, ear plugs should be deeply 

inserted into ear canals, and cushions on 

ear muffs should not be cracked or 

creased, and the head bands not sprung. 

3. Place warning signs that identify loud 

noise areas on doors and require 

employees entering these areas to wear 

hearing protectors. 

4. Consider using sound-absorbing 

materials that are easy to keep clean and 

dry on ceilings and floors of kennel 

areas. 

5. Consult an acoustical engineer when 

considering any future design changes to 

the facilities to determine whether noise 

exposures can be reduced. 

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as an environmental problem. J Am Vet Med 

Assoc 66 (11):1065-1068. 

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Occupational noise levels during emergency 

relief operations in the aftermath of Hurricane 

Katrina. Journal of Occupational and 

Environmental Hygiene (accepted). 

 3. Reid A, Dick F, Semple S [2004]. Dog 

noise as a risk factor for hearing loss among 

police dog handlers. Occup Med (London) 54 

(8):535-539. 

 4. NIOSH [2006]. Health hazard evaluation 

report: Cincinnati Police Canine Unit, 

Cincinnati, OH. Cincinnati, OH: U.S. 

Department of Health and Human Services, 

Public Health Service, Centers for Disease 

Control and Prevention, National Institute for 

Occupational Safety and Health, NIOSH Report 

No. 2006-0223-3029. 

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policy documents and statements. Cincinnati, 

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Services, Public Health Service, Centers for 

Disease Control and Prevention, National 

Institute for Occupational Safety and Health, 

DHHS (NIOSH) Publication No. 92-100. 

 6. CFR [1992]. 29 CFR 1910.95. Code of 

Federal Regulations. Washington, DC: U.S. 

Government Printing Office, Office of the 

Federal Register. 

 7. Ward WD, Royster LH, Royster JD 

[2000]. Anatomy & physiology of the ear: 

normal and damaged hearing. Chapter 4. In: 

Berger EH, Royster LH, Royster JD, Driscoll 

DP, & Layne M, eds. The noise manual. 5th ed. 

Fairfax, VA: American Industrial Hygiene 

Association, pp 101–122. 

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

hearing-impaired individuals to discriminate 

speech in noise. Washington, DC: U.S. 

Environmental Protection Agency, Joint 

EPA/USAF study, EPA 550/9–78–100, AMRL–

TR–78–4. 

 9. NIOSH [1998]. Criteria for a 

recommended standard: occupational noise 

exposure (revised criteria 1998). Cincinnati, OH: 

U.S. Department of Health and Human Services, 
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Centers for Disease Control and Prevention, 

National Institute for Occupational Safety and 

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 10. ANSI [1996]. American national standard 

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 11. 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 1745. 

 12. Suter AH [2002]. Hearing conservation 

manual. 4th ed. Milwaukee, WI: Council for 

Accreditation in Occupational Hearing 

Conservation. 

 13 Dobie RA, Rabinowitz PM [2002]. 

Change in audiometric configuration helps to 

determine whether a standard threshold shift is 

work-related. Spectrum 19 (Suppl 1):17. 

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Esteban E, Rubin C, Brody DJ [2001]. 

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threshold shifts among children 6 to 19 years of 

age: The Third National Health and Nutrition 

Examination Survey, 1988-1994, United States. 

Pediatrics 108(1):40-43. 

 15. Cooper JC, Owen JH [1976]. Audiologic 

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the audiometric configuration to determine 

whether hearing loss is noise-induced: Can 

“Notch Criteria Help?” NHCA Spectrum 

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[1997]. A re-examination of risk estimates from 

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hearing loss. Occup Environ Med 58:46-51. 

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Page 8 Health Hazard Evaluation Report No. 2006-0222-3037 

TABLES

Table 1 

Full-Shift Personal Dosimetry Results 

for 12 SPCA-Cincinnati Kennel Workers 

 

Sample Duration 

(hh:min) 

Noise Levels (Percent Dose) 

 OSHA AL OSHA PEL NIOSH REL 

8:29 110.7 98.5 973.1 

11:24 34.3 28.5 300.1 

9:28 120.3 100.1 1060.6 

10:32 163.3 145.8 1338.2 

9:52 86.5 79.5 607.9 

10:16 65.0 49.6 600.9 

9:23 15.1 11.9 94.1 

9:20 51.7 33.4 321.7 

3:47 11.6 5.9 47.2 

5:57 31.4 22.4 213.2 

8:58 78.0 66.1 528.1 

9:30 136.3 121.3 1173.8 

6:55 27.0 16.7 136.5 

9:46 104.2 89.3 985.7 

9:10 162.5 157.8 1300.8 

9:24 26.4 21.0 174.6 

9:09 96.1 82.9 854.5 

8:31 17.8 13.3 146.7 

5:38 25.9 18.1 179.1 

 The various dose percentages are the amounts of noise accumulated during a work day, with 100% 

 representing the maximum allowable daily dose. 

 SPCA: Society for the Prevention of Cruelty to Animals 

 OSHA: Occupational Safety and Health Administration 

 NIOSH: National Institute for Occupational Safety and Health 

 AL: Action Level 

 PEL: Permissible Exposure Limit 

 REL: Recommended Exposure Limit 
Health Hazard Evaluation Report No. 2006-0222-3037 Page 9 

Table 2 

Relationship between Hearing Loss (> 25 decibels) and Notch Formation 

for SPCA-Cincinnati Kennel and Non-Kennel Workers 

Employee ID Hearing Loss Notch (Hertz) 

 Left Ear Right Ear Left Ear Right Ear 

A No No 4000 4000 

B Mild to Moderate Mild to Moderate 3000–4000* 6000 

C No No No No 

D No Mild No 6000 

E No No No No 

F No No No No 

G No No 3000, 4000 No 

H Mild hearing loss Mild to Moderate 6000 6000 

I No No 6000 6000 

J No No No 6000 

K No No No No 

L Moderate hearing loss Mild 3000, 6000 4000, 6000 

M Moderate hearing loss Mild to Moderate 3000 6000 

N No No No No 

O Mild to Moderate Mild to Moderate 6000 No 

P Mild to Moderate None No No 

Q No Mild 6000 6000 

R No No No No 

S Mild to Moderate Mild No No 

SPCA: Society for the Prevention of Cruelty to Animals 

*Hearing levels formed a plateau at 3000 and 4000 Hertz before improving at 6000 Hertz 
Page 10 Health Hazard Evaluation Report No. 2006-0222-3037 

FIGURE

Figure 1 

Median Hearing Levels and Inter-Quartile Ranges 

for 19 SPCA-Cincinnati Kennel and Non-Kennel Workers 

0

5

10

15

20

25

012345678

Frequency (kHz)

Hearing Level [dB HL]

Left Ear Right Ear

 SPCA: Society for the Prevention of Cruelty to Animals 

Frequency (kHz) Left Ear Right Ear 

 25th percentile 75th percentile 25th percentile 75th percentile 

0.5 10 18 10 15 

1 5 10 5 8 

2 5 10 3 15 

3 0 20 5 15 

4 0 23 3 23 

6 5 28 0 33 

8 3 35 -5 23 
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contact NIOSH at: 

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