HETA 92-080-2284 NIOSH INVESTIGATORS:

FEBRUARY 1993 Steven A. Lee, CIH

MORENO VALLEY ANIMAL CONTROL Thomas Hales, MD

MORENO VALLEY, CALIFORNIA

 I. SUMMARY

On December 9, 1991 the National Institute for Occupational Safety and

Health (NIOSH) received a request from employees of the Moreno Valley

Animal Control (MVAC) to conduct a health hazard evaluation. The

requestors were concerned about possible exposure to euthanasic agents

resulting from needlestick injuries and exposure to flea/tick spray

(pyrethrin) and cleaning products. After initial contact with the

requestors, the evaluation expanded to include: 1) the potential for

exposure to human bloodborne diseases during the euthanasia process, and

2) odors emanating from the refrigerator used to store dead animals. 

An inspection of the facility was conducted on July 20-21, 1992. Air

samples were collected during the process of spraying the animals with a

0.1% solution of pyrethrin, and work practices were observed during the

euthanasia process. Current workers employed as kennel technicians

(KTs) or animal control officers (ACOs) were interviewed regarding

health symptoms, medical conditions, and work practices. Former

employees were interviewed by telephone.

None of the three short-term air samples collected in the personal

breathing zones of ACOs found detectable levels of pyrethrin (< 1

mg/M3). The NIOSH Recommended Exposure Limit for pyrethrin is 5 mg/M

Observations of work practices during the use of cleaning products (all

common consumer items) indicated that excessive exposures would be

unlikely. Also, it was concluded that the amount of euthanasic agent

(pentobarbital and potassium chloride) that would plausibly be injected

unintentially during a needlestick injury would be too small to pose any

health risk. There was a putrid odor from decaying road-killed animals

in the walk-in refrigerator, and this odor permeated the adjacent

euthanasia room. 

Two of the former employees had experienced respiratory symptoms which

had resolved after discontinuing work. These symptoms were not

consistent with asthma, however, they could have been upper airway

irritant or allergic reactions related to animal exposure. None of the

current employees reported respiratory, dermatologic, or neurologic

symptoms associated with their work. Most of the current and former

employees acknowledged the unpleasant odor in the refrigerator and the

euthanasia room, with many employees reporting nausea and/or mild

headaches that they associated with the odor. 

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
Over half of the 17 current and former employees interviewed reporte

sticking themselves with a needle at least once during their employm

with MVAC. Although ACOs rarely reused needles, KTs, on the other h

reported that they almost always reused needles, with most employees

killing three or four animals with the same needle and occasionally

recapping and saving the needle for later use. 

In 1992, one employee was diagnosed with previous infection with

hepatitis B (HBV) and current infection with hepatitis C (HCV). 

Serologic tests for the HBV were negative in 1986 during a blood

donation. The employee reported none of the risk factors associated

with HBV and HCV infections. This investigation could not determine 

source of these infections, but non-primate animals are not known to 

sources of HBV or HCV.

Based on the results of this investigation, there was no health haza

from exposure to euthanasic agents, pyrethrin or cleaning products a

the time of the NIOSH visit. Whether the respiratory symptoms

experienced by two former employees represented work-related upper

airway irritant or allergic reactions could not be determined from

this evaluation. Although the opportunity for exposure to human blo

by needlestick was extremely small, NIOSH recommended that MVAC adop

the policy of not reusing or recapping needles. Suggestions for

reducing the odor of decaying animals at MVAC are contained in Secti

IX of this report. 

KEYWORDS: SIC 0752 (Animal Specialty Services), bloodborne diseases

hepatitis B, hepatitis C, pyrethrin, respiratory symptoms, 

neurobehaviorial symptoms, neurologic symptoms. 
Page 3 - Health Hazard Evaluation Report 92-080-XXXX

II. INTRODUCTION

On December 9, 1991, the National Institute for Occupational Safety 

Health (NIOSH) was requested by employees of Moreno Valley Animal

Control (MVAC) to evaluate their potential exposure to euthanasic

agents, bloodborne pathogens, pesticides, cleaning products, and

decaying animals while working at the facility. Reported health

symptoms included respiratory, neurologic (arm numbness), and

neurobehavioral (headaches, dizziness, nausea) symptoms. The medica

conditions of concern were bloodborne diseases (hepatitis B, hepatit

C, HIV). To evaluate these concerns, NIOSH investigators conducted 

site visit on July 20-21, 1992.

III. BACKGROUND

The MVAC facility was established in June 1991, in a renovated build

that initially served as a turkey hatchery for several decades and a

metal duct warehouse for another decade. MVAC is responsible for 1

impounding stray animals; 2) caring for these impounded animals unti

they are picked up by their owners, adopted, or destroyed (after 5-1

days); 3) enforcing the city's animal control laws; 4) responding to

citizen complaints regarding animals; and 5) collecting and disposin

animals killed on the city's streets and highways.

The facility is staffed by approximately 17 full and part-time emplo

and 6 to 10 county jail "trustees" fulfilling community service

obligations. Trustees are responsible for cleaning the floors and c

of the 64 kennels. The cleaning compounds are typical household

products, such as abrasive cleanser, window cleaner, and bleach. Th

job titles for the 17 paid employees are: Animal Control Officers (4

Kennel Technicians (4), Dispatch (2), and Clerical (7). Over the pa

13 months of operation there has been a 142% turn-over among paid

employees.

Animal Control Officers (ACOs) impound approximately 1000 animals pe

month, split evenly between dogs and cats. Most animals are unloade

the garage and sprayed with Ken AG Aqueous Fly Spray, which contains

0.1% pyrethrin. The product is dispensed from either a pressurized 

gallon Smith "Home and Garden Sprayer" or a 32-ounce hand-pump spray

Spraying requires about 2 minutes per animal. Although other flea a

tick control products are available (dips, dusts, and shampoos) at t

facility, these are rarely used. 

The animals are housed in the kennels for 5 to 15 days. Almost half 

the impounded dogs are adopted, but a much smaller percentage of cat

find homes, leaving approximately 800 animals per month to be destro

Generally, the Kennel Technicians (KTs) are responsible for the

euthanasia process, which typically requires two employees. One hold
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the animal, while the other injects the euthanasic agent (mixture of

sodium pentobarbital and potassium chloride) intravenously. Current

MVAC requires individuals injecting the animals be "certified" in

euthanasia. MVAC does not have a policy on the re-use of needles. 

Individual employees use anywhere from two to ten injections per nee

A walk-in refrigerator, kept at about 40°F, is attached to the

euthanasia room. The refrigerator is used for storing dead animals

which are removed from the facility each Friday.

On November 12, 1991 an MVAC employee was hospitalized for acute

respiratory and chest symptoms possibly due to chemical exposures at 

facility. Although the etiology of these symptoms was not determine

this hospitalization, a formal complaint was filed with the Californ

Occupational Safety and Health Administration (CAL-OSHA). On Novemb

19, 1991, CAL-OSHA conducted an on-site inspection and cited MVAC fo

not having 1) a written emergency action plan, 2) a written fire

prevention plan, and 3) a written hazard communication plan. A

noticeable odor was noted in the walk-in freezer, but a citation was 

issued due to the lack of an OSHA standard for putrid odors.

 IV. EVALUATION DESIGN AND METHODS

A. ENVIRONMENTAL

On July 20-21, 1992, NIOSH investigators conducted an inspectio

of the facility and collected air samples during the applicatio

of flea and tick spray. Three short-term personal breathing-zo

air samples were collected from two ACOs as they sprayed dogs w

an aqueous solution containing 0.1% pyrethrin. The samples wer

collected on glass fiber filters at a flow rate of 2 liters per

minute and analyzed by high performance liquid chromatography

according to NIOSH Method 5008.1

 

B. MEDICAL

The NIOSH physician interviewed the current and former KTs and

ACOs regarding health symptoms, health conditions, and work

practices. 

 V. EVALUATION CRITERIA AND HEALTH EFFECTS

A. ENVIRONMENTAL

As a guide to the evaluation of the hazards posed by workplace

exposures, NIOSH field staff employ environmental evaluation criteri

for assessment of a number of chemical and physical agents. These

criteria are intended to suggest limits of exposure to which most

workers may be exposed up to ten hours per day, 40 hours per week fo

working lifetime without experiencing adverse health effects. It is
Page 5 - Health Hazard Evaluation Report 92-080-XXXX

however, important to note that not all workers will be protected fo

adverse health effects if their exposures are maintained below these

limits. A small percentage may experience adverse health effects

because of individual susceptibility, a pre-existing medical conditi

and/or a hypersensitivity (allergy). In addition, some hazardous

substances may act in combination with other workplace exposures, th

general environment, or with medications or personal habits of the

worker to produce health effects even if the occupational exposures 

controlled at the limit set by the criterion. These combined effect

are often not considered in the evaluation criteria. Also, some

substances are absorbed by direct contact with the skin and mucous

membranes, and thus potentially increase the overall exposure. Fina

evaluation criteria may change over the years as new information on 

toxic effects of an agent become available.

The primary sources of environmental evaluation criteria for the

workplace are the following: 1) NIOSH Recommended Exposure Limits

(RELs), 2) the American Conference of Governmental Industrial

Hygienists' (ACGIH) Threshold Limit Values (TLVs), and 3) the U.S.

Department of Labor, Occupational Safety and Health Administration

(OSHA) Permissible Exposure Limits (PELs). The OSHA PELs may be

required to take into account the feasibility of controlling exposur

in various industries where the agents are used; the NIOSH RELs, by

contrast, are base primarily on concerns relating to the prevention 

occupational disease. 

A time-weighted average (TWA) exposure refers to the average airborn

concentration of a substance during a normal 8- to 10-hour workday. 

Some substances have recommended short-term exposure limits (STELs) 

ceiling values which are intended to supplement the TWA where there 

recognized toxic effects from high, short-term (15 minute) exposures

Pyrethrin

Pyrethrin is an insecticide obtained from the chrysanthemum pla

Exposure can cause dermatitis, upper respiratory symptoms

(sneezing, rhinitis), and allergic asthma.2-4 In a study of

California pet handlers, exposure to pyrethrin was only associa

with "stomach" pains, which the authors noted, was not consiste

with the known toxicity of pyrethrin.5 The NIOSH, ACGIH, and O

evaluation criteria for exposure to airborne pyrethrin is 5

milligrams per cubic meter (mg/m3), as an 8-hour TWA exposure.
Page 6 - Health Hazard Evaluation Report 92-080-XXXX

B. MEDICAL

The major infections transmitted by blood are hepatitis B (HBV),

hepatitis C (HCV), and human immunodeficiency virus type 1 (HIV). T

is no evidence of non-primate animal-to-human transmission of these

viruses. Non-primate animals are not known to be suseptible to

infections by these viruses.

1. Hepatitis B Virus (HBV)

HBV is a major cause of acute and chronic hepatitis, cirrhosis,

and primary hepatocellular carcinoma worldwide.9 Transmission 

HBV occurs by percutaneous or permucosal routes, and infective

blood or body fluids can be introduced at birth, through sexual

contact, or by contaminated needles.10 Persons at increased ris

of acquiring HBV infection include members of the following

groups: a) parenteral drug users, b) heterosexual men and women

and homosexual men with multiple partners, c) household contact

and sexual partners of HBV carriers, d) infants born to HBVinfected mother, e) patients and staff in custodial institution

for the developmentally disabled, f) recipients of certain plas

derived products (including patients with congenital coagulatio

defects), g) hemodialysis patients, h) health and public-safety

workers who have contact with blood, and i) persons born in are

of high HBV endemicity and their children.10 For approximately 

of whites and 14% of blacks with HBV infections, no risk factor

are identified.11 

HBV can survive for at least one week dried at room temperature 

environmental surfaces, and disinfection, sterilization, and

disposal procedures must be adequate to prevent the spread of t

virus.12 The Centers for Disease Control (CDC) has estimated th

12,000 health-care workers whose jobs entail exposure to blood

become infected with HBV each year.13 Needle stick injuries mak

up a significant portion of these infections; 6%-30% of persons

receiving a needle-stick exposure from an HBV antigen-positive

individual (HBsAg) will become infected.14 Although animal

handlers have not been specifically studied, there is no reason 

suspect that they would normally be at risk of occupationally

acquired hepatitis B since animals other than primates infected 

laboratories are not a potential source of infection.

2. Hepatitis C Virus (HCV)

In May 1990, serologic tests that detect anti-HCV antibody by E

were licensed and became commercially available in the United

States. Studies have shown that HCV is the etiologic agent of 

majority of parenterally transmitted or bloodborne non-A, non-B

hepatitis worldwide.10 Because the serologic tests diagnostic o
Page 7 - Health Hazard Evaluation Report 92-080-XXXX

HCV infection have only recently become available, the natural

history of this infection needs further study, but links with

acute and chronic hepatitis and cirrhosis are well established.

The mode of transmission is, in one respect, similar to that of

HBV, with parenteral drug users, health-care workers with

occupational exposure to blood, hemodialysis patients, and

recipients of whole blood, blood cellular components, or plasma

being at increased risk.10 Sexual activity and other types of

person-to-person contact, however, have not been generally

recognized as important mechanisms of transmission.10 In

addition, 40% of patients with acute HCV infection have no

identifiable risk factors.15 

3. Human Immunodeficiency Virus Type 1 (HIV)

HIV adversely affects the immune system, rendering the infected

individual vulnerable to a wide variety of infections and other

conditions. When an HIV infected individual contracts one of

several specified clinical disorders, that individual is diagno

with acquired immunodeficiency syndrome (AIDS). Transmission o

HIV is similar to that of HBV. Groups at higher risk include 1

homosexual and bisexual men, 2) parenteral drug users, and 3)

heterosexuals with multiple sexual partners, HIV-infected sexua

partners, or sexual partners at risk for HIV infection). These

groups account for over 89% of AIDS cases,16 and over 80% of HIV

infections.17 Occupational transmission of HIV has been

documented in health care workers. As of May 1990, information

submitted to the public record indicates at least 65 cases of

healthcare workers whose HIV infections were associated with

occupational exposure.18 Eighteen of the 30 case reports

published in the scientific literature as of may 1990

seroconverted following a documented exposure incident. Eleven 

these 18 seroconversions were caused by needlesticks.18 The

actual risk of seroconverting following a needlestick with HIVinfected blood is approximately 0.4%.19 As with the HBV and HCV

no studies have identified animal handlers being at increased r

for occupationally acquired HIV infections.
Page 8 - Health Hazard Evaluation Report 92-080-XXXX

 VI. RESULTS AND DISCUSSION

A. ENVIRONMENTAL

Exposure to pyrethrin was below the sampling and analytical limit of

detection (< 1 mg/M3) at the time of the NIOSH visit. The NIOSH

Recommended Exposure Limit for pyrethrin is 5 mg/M3. Overexposure t

pyrethrin was considered to be unlikely at this facility due to the

small amounts of dilute solution being used and the short durations 

exposure.

Observations of cleaning practices revealed no unusual or hazardous

practices and indicated that excessive exposure to cleaning products

would be unlikely as long as the product label instructions are

followed. 

B. MEDICAL

All nine currently employed KTs and ACOs were interviewed. Of the 1

former KTs and ACOs, 2 were interviewed in person, 6 six were

interviewed by telephone, and 6 could not be located.

1. Symptoms

None of the current workers complained of skin, neurologic, or

respiratory symptoms associated with work, but two former

employees reported work-related respiratory symptoms which

resolved after discontinuing work. Although these respiratory

symptoms were not suggestive of asthma, they could have

represented upper airway or irritant reactions related to anima

exposure. All of the current and former workers noted the

unpleasant odor from decaying road-killed animals in the walk-i

refrigerator. Many employees stated the odor caused minimal

nausea and/or mild headaches.

2. Work Practices

Four of the nine (44%) current employees reported sticking

themselves with a needle at least once during their employment

with MVAC. The stick typically occurred during the injection

procedure or re-capping process. Two (22%) reported seeing oth

employees sticking themselves. Four of the 8 (50%) former

employees interviewed reported sticking themselves with needles 

least once while employed with MVAC. Seven of the 8 (88%)

reported seeing other employees sticking themselves.

Current and former ACOs rarely reused needles. If needles were

reused, never were there more than two animals killed with the

same needle. KTs, on the other hand, reported that they almost
Page 9 - Health Hazard Evaluation Report 92-080-XXXX

always reused needles, with most employees destroying three or

four animals with the same needle. Occasionally, used needles

were recapped and saved for later use. 

3. Medical Conditions

In 1992, one employee was diagnosed with previous infection wit

HBV and current infection with HCV. Serologic tests for the HB

were negative in 1986 during a blood donation. This employee

reported none of the risk factors associated with HBV and HCV

infections. This investigation could not determine the source 

this employee's HBV and HCV infection other than to note that t

HBV infection occurred sometime between 1986 and 1992. As

discussed earlier, there would be no reason to suspect that HBV 

HCV infection would be related to contact with animals or anima

blood (other than from laboratory-infected primates). 

 

 VII. CONCLUSIONS

Based on the NIOSH investigators' observations of current work

practices, the environmental sampling data for pyrethrin, and the

general lack of persistent symptoms experienced by employees, we

conclude that employees of MVAC were not at increased risk for adver

health conditions due to chemical exposures. Acute respiratory symp

could possibly represent upper airway irritant or allergic reactions 

to animal exposure. The odor of decaying animals probably contribut

to employee discomfort, but no long-term health effects are known to

result from this exposure.

Although the opportunity for exposure to human blood by needlestick

during the euthanasia process is theoretically possible (e.g., by tw

employees being stuck by the same needle), it is highly unlikely. 

However, any possible exposure to bloodborne pathogens merits seriou

concern. Therefore, the following recommendations should be followe

minimize this hazard. 

VIII. RECOMMENDATIONS

1. MVAC should forbid the practice of reusing or recapping needles

2. Needles should be immediately discarded when a needlestick occu

This is particularly important when two people are performing t

euthanasia, in order to minimize the possibility of a second

needlestick (to the other worker).

3. Needles should be discarded, without recapping, in containers t

are closable, puncture resistant, and leakproof on the sides an

bottom.
Page 10 - Health Hazard Evaluation Report 92-080-XXXX

4. Cleaning workers should be trained to use cleaning products

strictly in accordance with the label warnings and instructions

This is particularly important when diluting concentrated produ

and adhering to warnings about the mixing of multiple products. 

For example, mixing bleach with other cleaning products may

release hazardous levels of chlorine gas. 

5. The odor of decaying animals should be reduced. Possible

solutions may include:

a) venting the refrigerated air outside the building, 

b) moving the refrigerator out of the building, 

c) increasing the frequency of removing dead animals from the 

 facility, or

d) reducing the storage temperature to below freezing.

6. A quarterly respiratory symptom questionaire should be distribu

to employees exposed to animals. Workers with symptoms should 

referred to health care providers for further evaluation. 

 IX. REFERENCES

1. NIOSH [1984]. NIOSH manual of analytical methods. 3rd ed. 

Cincinnati, OH: National Institute for Occupational Safety and

Health. DHHS (NIOSH) Publication No. 84-100. 

2. Casida, J.E.(ed.) Pyrethrum - The Natural Insecticide. Academ

Press, NY, 1973, p. 123-142.

3. NIOSH/OSHA [1981]. Occupational safety and health guideline fo

pyrethrum. In: NIOSH/OSHA. Occupational safety and health

guidelines for chemical hazards. Cincinnati, OH: U.S. Departme

of Health and Human Services, Public Health Service, Centers fo

Disease Control, National Institute for Occupational Safety and

Health, DHHS, (NIOSH) Publication No. 81-123.

4. Zenz, Carl (ed.). Occupational medicine: principles and practi

applications. 2nd ed. Chicago, IL: Year Book Medical Publishers

Inc., p. 687.

5. Ames RG, Brown SK, Rosenberg J, Jackson RJ, Stratton JW, Quenon

SG. Health symptoms and occupational exposure to flea control

products among California pet handlers. Am. Ind. Hyg. Assoc. J

1989;50(9):466-472.

6. CDC (Centers for Disease Control) [1988]. NIOSH recommendation

for occupational safety and health standards. MMWR 37 (suppl. 

S-7).
Page 11 - Health Hazard Evaluation Report 92-080-XXXX

7. ACGIH [1991]. 1991-92 threshold limit values for chemical

substances and physical agents, and biological exposure indices

Cincinnati, OH: American Conference of Governmental Industrial

Hygienists.

8. Code of Federal Regulations [1989]. Air contaminants -

permissible exposure limits. 29 CFR 1910.1000. U.S. Departmen

of Labor, Occupational Safety and Health Administration (OSHA).

 9. Maynard JE, Kane MA, Alter MJ, Hadler SC. Control of hepatitis 

by immunization: global perspectives. In: Zukerman AJ, (ed.)

Viral hepatitis and liver disease. New York: Alan R. Liss, Inc

1988:967-9.

10. CDC (Centers for Disease Control) [1991]. Public health servic

inter-agency guidelines for screening donors of blood, plasma,

organs, tissues, and semen for evidence of hepatitis B and

hepatitis C infection. MMWR 40 (Suppl No. RR-4).

11. McQuillan GM, Townsend TR, Fields HA, et al. 

Seroepidemiology of hepatitis B virus infection in the United

States: 1976 to 1980. Am J Med 1989;87(3A):5S-10S.

12. Bond WW, Favero MS, et al [1981]. Survival of hepatitis B viru

after drying and storage for one week. Lancet; March 7:550-551

13. CDC (Centers for Disease Control) [1989]. Guidelines for

prevention of transmission of human immunodeficiency virus and

hepatitis B virus to health-care and public-safety workers. MM

38 (Suppl No. S-6).

14. CDC (Centers for Disease Control) [1985]. Recommendations for

protection against viral hepatitis. MMWR 34:313-324, 329-335.

15. Wright TL. Transmission of hepatitis C. Liver Update: Functio

and Disease 1992;6(3):5-6.

16. CDC (Centers for Disease Control) [1992]. Update: acquired

immunodeficiency syndrome - United States, 1991. MMWR 41(26):4

468.

17. CDC (Centers for Disease Control) [1991]. Publicly funded HIV

counseling and testing - United States, 1990. MMWR 40(39):666-

675.

18. 56 Federal Register 234 [1991]. Occupational Safety and Health

Administration: Occupational exposure to bloodborne pathogens;

final rule. 29 CFR Part 1910.1030.
Page 12 - Health Hazard Evaluation Report 92-080-XXXX

19. Marcus R, and the CDC Cooperative Needlestick Surveillance Grou

Surveillance of health care workers exposed to blood from patie

infected with the human immunodeficiency virus. N Eng J Med

1988;319:1118-23.

 X. AUTHORSHIP AND ACKNOWLEDGEMENTS

Report Prepared by: Steven A. Lee, CIH

Regional Industrial Hygienist

Thomas Hales, MD

Regional Medical Consultant

Originating Office: Hazard Evaluations and Technical 

Assistance Branch,

Division of Surveillance, Hazard 

Evaluations, and Field Studies

NIOSH Region VIII

 XI.DISTRIBUTION AND AVAILABILITY OF REPORT

Copies of this report may be freely reproduced and are not copyright

Single copies of this report will be available for a period of 90 da

from the date of this report from the NIOSH Publications Office, 467

Columbia Parkway, Cincinnati, Ohio 45226. To expedite your request

include a self-addressed mailing label along with your written reque

After this time, copies may be purchased from the National Technical

Information Service (NTIS), 5825 Port Royal Road, Springfield, Virgi

22161. Information regarding the NTIS stock number may be obtained 

the NIOSH Publications Office at the Cincinnati address.

Copies of this report have been sent to:

1. Moreno Valley Animal Control, Moreno Valley, California

2. Requestors

3. OSHA Region IX

For the purpose of informing affected employees, copies of this repo

shall be posted by the employer in a prominent place accessible to t

employees for a period of 30 calendar days.