Evaluation of 

Exposures Associated 

with Cleaning 

and Maintaining 

Composting Toilets – 

Arizona

Nancy Clark Burton, PhD, MPH, CIH

Chad Dowell, MS, CIH

Health Hazard Evaluation Report

HETA 2009-0100-3135

July 2011

DEPARTMENT OF HEALTH AND HUMAN SERVICES

Centers for Disease Control and Prevention

Workplace

Safety and Health

 National Institute for Occupational 

Safety and Health

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/
The employer shall post a copy of this report 

for a period of 30 calendar days at or near 

the workplace(s) of affected employees. The 

employer shall take steps to insure that the 

posted determinations are not altered, defaced, 

or covered by other material during such 

period. [37 FR 23640, November 7, 1972, as 

amended at 45 FR 2653, January 14, 1980].
Health Hazard Evaluation Report 2009-0100-3135 Page i

Report Abbreviations................................................................................................ii

Highlights of the NIOSH Health Hazard Evaluation........................iii

Summary .........................................................................................................v

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

Assessment.....................................................................................................1

Results..............................................................................................................2

Discussion.......................................................................................................8

Conclusions................................................................................................. 10

Recommendations.................................................................................... 10

References.................................................................................................... 13

Contents

Acknowledgments

Appendix A

Appendix B 

Occupational Exposure Limits and Health Effects......................... 15

Confined Space Entry Requirements................................................. 20

Acknowledgments and Availability of Report................................ 23
Page ii Health Hazard Evaluation Report 2009-0100-3135

Abbreviations

ACGIH® American Conference of Governmental Industrial Hygienists

CDC Centers for Disease Control and Prevention

CL Ceiling limit

CFR Code of Federal Regulations

HAV Hepatitis A virus

HBV Hepatitis B virus

HHE Health hazard evaluation

HPS Hantavirus pulmonary syndrome

IDLH Immediately dangerous to life or health

LFL Lower flammable limit

ND Not detected

NAICS North American Industry Classification System

NIOSH National Institute for Occupational Safety and Health

OEL Occupational exposure limit

OSHA Occupational Safety and Health Administration

PAPR Powered air-purifying respirator

PBZ Personal breathing zone

PPE Personal protective equipment

PEL Permissible exposure limit

ppm Parts per million

REL Recommended exposure limit

STEL Short-term exposure limit

TLV® Threshold limit value

TWA Time-weighted average

U.S. EPA United States Environmental Protection Agency

WEELTM Workplace environmental exposure level 
Health Hazard Evaluation Report 2009-0100-3135 Page iii

The National Institute for 

Occupational Safety and 

Health (NIOSH) received 

a request for a health 

hazard evaluation at a 

national park in Arizona. 

Management submitted 

the request because 

of concerns about 

exposures to employees 

cleaning and maintaining 

pit and composting 

toilets. The request also 

asked for an evaluation 

of personal protective 

equipment (PPE) use.

Highlights of the

NIOSH Health

Hazard Evaluation

What NIOSH Did

● We visited the park in May 2009.

● We talked with management and employees about their 

concerns.

● We observed employee work practices and PPE use.

● We reviewed the park’s written respiratory protection 

program. We also reviewed material safety data sheets for 

cleaners and bacteria additives used at the park.

● We collected personal breathing zone and area air samples 

for ammonia, hydrogen sulfide, enteric bacteria (as an 

indicator of fecal contamination), and thermophilic 

actinomycetes (as an indicator of the microbial 

contamination found at the higher temperatures needed to 

compost organic material).

What NIOSH Found

● Ammonia concentrations were higher when the pit toilets 

were opened than when the composting toilets were opened. 

These concentrations dropped quickly when the ammonia 

was exposed to air.

● Air sampling showed that thermophilic bacteria were present 

when the employees worked with the composting toilets.

● Hydrogen sulfide and enteric bacteria were not found in air 

samples.

● Work tasks required manual shoveling and lifting and some 

awkward postures.

● Working in the park puts employees at risk for extreme heat, 

bee and scorpion stings, spider bites, and hantavirus from 

rodent nests and feces.

● Employees may be exposed to hepatitis A virus (HAV) when 

handling untreated human waste and trash. Employees may 

also be exposed to hepatitis B virus (HAB) while doing other 

job duties as first responders.

What Managers Can Do

● Use metal supports to allow the contents of the pit toilets to 

be dumped directly into the storage container for disposal.
Page iv Health Hazard Evaluation Report 2009-0100-3135

Highlights of the

NIOSH Health

Hazard Evaluation

 (continued)

● Increase how often preventive maintenance is performed on 

toilets. This will allow issues such as blocked leachate lines to 

be identified and addressed more quickly.

● Include trail maintenance crews in current bloodborne 

pathogen program, and require employees to take annual 

training.

● Start a voluntary vaccination program for HAV and HBV for 

the trail and toilet maintenance crews.

● Develop standard medical follow-up protocols for bee and 

scorpion stings and spider bites.

● Implement a confined space program. This program should 

be followed when entering and emptying the composting 

toilet vaults.

● Start a heat stress program for the trail and toilet 

maintenance crews.

What Employees Can Do

● Wear the right PPE for the work you are doing including 

gloves, protective clothing, and NIOSH-approved respirator.

● Clean your hands before eating, drinking, or smoking.

● Wait 1 minute after opening the lid of a pit toilet before 

servicing. This will allow the ammonia levels to dissipate.

● Seek prompt medical care for scorpion stings, bee stings, and 

spider bites.

● Get vaccinated for HAV if working with toilets and for HBV 

if your job involves first aid. 
Health Hazard Evaluation Report 2009-0100-3135 Page v

NIOSH evaluated 

exposures to park 

employees who cleaned 

and maintained pit and 

composting toilets. We 

found that employees 

who serviced the 

pit and composting 

toilets were potentially 

exposed to a wide range 

of hazards. Identified 

hazards included 

exposure to infectious 

agents, chemicals, 

wildlife, and ergonomic 

stressors and working 

in hot environments 

and confined 

spaces. Engineering, 

administrative, and PPE 

recommendations to 

reduce these exposures 

such as using a backhoe 

to dump pit toilets 

into a dumpster and 

establishing a heat stress 

program are included in 

this report.

Summary

In February 2009, NIOSH received an HHE request from 

management at a national park in Arizona. The request 

concerned employees’ potential exposures during the cleaning 

and maintenance of the pit and composting toilets in the park. 

Park management also wanted to know whether the PPE used by 

employees was appropriate. NIOSH investigators visited the park 

in May 2009. We held an opening meeting to discuss employer and 

employee concerns; observed work practices; talked to employees 

about their work and health; reviewed records; and collected air 

samples for ammonia, hydrogen sulfide, enteric bacteria, and 

thermophilic actinomycetes.

Our investigation showed that instantaneous ammonia 

concentrations were highest when the pit toilets were first opened, 

but these levels dropped very quickly. Thermophilic actinomycetes, 

an indicator of the microbial contamination found at the higher 

temperatures needed to compost organic material, were detected 

in PBZ air samples collected while employees cleaned composting 

toilets. No hydrogen sulfide or enteric bacteria were detected. 

Heat stress was not evaluated during this site visit but could be a 

potential problem on the basis of ambient temperatures, workload, 

and use of PPE observed.

Other potential exposures for employees included scorpion and 

bee stings, spider bites, and airborne hantavirus from rodent nests 

and rodent feces. Employees were also potentially exposed to 

hepatitis A and hepatitis B viruses through first responder duties 

and through handling of untreated human waste and feminine 

hygiene products. Shoveling out the toilets by hand resulted in 

awkward postures. One of the composting toilets had a blocked 

leachate line that caused liquid to back up into the waste vault. 

Working inside the composting toilet vault meets the criteria for 

a confined space under NIOSH guidelines. Recommendations to 

address these potential hazards, such as development of standard 

medical procedures to address scorpion and bee stings and spider 

bites, are included in this report.

Keywords: NAICS 712190 (Nature Parks and Other Similar 

Institutions), composting toilets, pit toilets, sewage, enteric bacteria, 

thermophilic actinomycetes, confined space, ammonia, personal 

protective equipment 
Page vi Health Hazard Evaluation Report 2009-0100-3135

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Health Hazard Evaluation Report 2009-0100-3135 Page 1

Introduction

On February 20, 2009, NIOSH received an HHE request from 

management at a national park in Arizona. The request was 

submitted because employees were concerned about exposures 

to human waste and wanted to know the appropriate PPE to use 

while cleaning and maintaining the three types of toilets used 

on the trails. NIOSH investigators conducted a site visit from 

May 12–15, 2009. An interim letter was sent in June 2009 with 

preliminary recommendations.

Assessment

We observed work processes, work practices, workplace 

conditions, and PPE use and spoke with employees about their 

potential exposures and health concerns. We reviewed the 

scientific literature concerning composting toilets and exposures 

associated with sewage. We also reviewed material safety data 

sheets for cleaning chemicals, standard operating procedures, 

and the written respiratory protection program. Dräger® shortterm colorimetric detection tubes were used to measure airborne 

concentrations of ammonia and hydrogen sulfide when opening 

the toilets [Dräger Safety Inc., Pittsburgh, Pennsylvania]. The 

ammonia tubes have a standard measurement range of 5 to 100 

ppm during a 10-second sampling period, and the hydrogen 

sulfide tubes have a range of 2 to 200 ppm during a 3.5-minute 

sampling period [Dräger 2011].

Task-based PBZ and area air samples were collected using a 0.3-

micrometer pore-size 37-millimeter polytetrafluoroethylene filter 

in conjunction with an SKC AirChek 2000 sampling pump 

at a flow rate of 2 liters per minute (SKC Inc., Eighty Four, 

Pennsylvania). Samples were collected during pit and composting 

toilet cleaning and were analyzed for culturable enteric bacteria 

and culturable thermophilic actinomycetes (composting toilet 

cleaning only). An additional area air sample for enteric bacteria 

and thermophilic actinomycetes was collected below the 

composting toilets along the major trail. All sampling pumps 

were precalibrated and postcalibrated with a DryCal DC Lite 

(Bios International Corporation, Butler, New Jersey). Additional 

information regarding relevant OELs and health effects can be 

found in Appendix A.
Page 2 Health Hazard Evaluation Report 2009-0100-3135

Results

Process Observations

Two groups of employees were potentially exposed – the compost 

crew and the rangers/trail crews. The compost crew cleaned the 

toilets and removed excess material in all three types of toilets 

used in the park – Romtec (pit), Phoenix (composting), and Clivus 

(composting). Maintenance of the pit toilets, performed by both 

groups of employees, included stirring the piles; general cleaning 

of the units using Simple Green®, a detergent solution containing 

2-butoxyethanol; removing trash from the toilets; and restocking of 

supplies. PPE used for maintenance included latex or nitrile gloves, 

rubber outer gloves, and safety glasses. Alcohol hand wash (62% 

ethanol) was used for hand cleaning. General maintenance of the 

trail composting toilets included replacing toilet paper, adding 

wood chips and sewage treatment bacteria, sweeping floors and 

cleaning surfaces, removing trash and replacing trash can liners, 

mopping floors, and stirring and raking the toilet contents. This 

work was done by the composting crew and the rangers/trail crews.

The Romtec units were used in the back country. These units were 

loaded onto large metal trays and flown in and out of the park by 

helicopter. Cleaning out the Romtec units consisted of removing 

the wet material and wood chips from the base with a shovel and 

putting them into a backhoe (Figure 1). The backhoe operator 

moved the wet material and wood chips to a large trailer where 

they were mixed in with other trash before being taken to an offsite municipal landfill. The compost crew wore nitrile gloves under 

rubber gloves, work boots, goggles, Tyvek® suit, and a facemask 

(Defend Model MK-1006). The employees voluntarily used 

facemasks to keep flies out of their noses and mouths rather than 

for respiratory protection. We noticed leakage from the backhoe’s 

split claw into the dirt pit when the employees shoveled out the 

Romtec toilets, potentially exposing them to untreated waste.

The large and heavy Romtec units were loaded onto a truck by 

two employees and driven to the wastewater treatment plant 

where they were scrubbed using brushes with a Simple Green® 

detergent solution (Sunshine Makers, Inc., Huntington Harbour, 

California), rinsed with water, and sanitized with a hypochlorite 

solution (11⁄2 cups of household bleach in 1 gallon of water) 

(Figure 2). The employees wore rubber waders over Tyvek suits, 

rubber boots, nitrile gloves under rubber gloves, and facemasks 

(Defend Model MK-1006).
Health Hazard Evaluation Report 2009-0100-3135 Page 3

Results

 (continued)

Figure 1. Employees in PPE shoveling 

material from a pit toilet into a backhoe 

clamshell shovel.

Figure 2. Employees in PPE cleaning 

pit toilet components at the wastewater 

treatment plant.
Page 4 Health Hazard Evaluation Report 2009-0100-3135

The Phoenix and Clivus composting toilets were designed to break 

down waste materials using naturally occurring bacteria and fungi 

and supplemental bacteria, which is added during toilet maintenance. 

A composting toilet is divided into an upper section for public 

use and below-ground composting tanks (Figure 3). The waste was 

turned using either solar battery-powered or wired electrical baffles. 

At least annually the composting crew removed the waste from the 

composting toilets. To prevent exposure to hantavirus, the crew used 

a hypochlorite solution (11⁄2 cups of household bleach in 1 gallon 

of water) in the lower section of the composting tanks if rodent 

droppings were present. Most of the work was shoveling the waste into 

bags (weight range: 36 to 74 pounds). The bags were carried out of the 

park by mule train and then taken to a landfill. During the NIOSH 

site visit, the compost crew wore latex or nitrile gloves under rubber 

gloves, work boots, Tyvek suits, and hooded 3M PAPRs with high 

efficiency particulate filters during active cleaning.

One of the composting toilets along the trail, installed in the 

1980s, reportedly had a nonfunctioning leachate line that caused 

liquid to build up in the composting vaults. As a result, it was 

necessary to add several bags of wood chips to soak up the liquid 

before the vault could be emptied. The wet wood chips were heavy 

and hard to shovel (Figure 4).

Occasionally, some of the waste got stuck in the toilet’s waste chute. 

To loosen the waste, the employee put his or her head and shoulders 

into the vault and used a shovel or a metal bar to dislodge the stuck 

waste. This vault was considered a confined space (Category C) 

under NIOSH definitions because it had a limited opening for entry 

and exit, unfavorable natural ventilation with potentially dangerous 

contaminants, and was not intended for continuous employee 

occupancy [NIOSH 1979]. The Phoenix toilets had a crank attached 

to baffles to help break up material so that it could fall into the vault. 

Employees reported that awkward postures and the weight of the 

material made it hard to shovel while squatting and filling bags (Figure 

5). We observed that employees did not lock the upstairs doors, and 

untreated waste fell on them when people used the facilities. The 

outside of the bags had some waste stuck to them, which was difficult 

to remove and could contact the workers’ and mules’ skin.

The compost crew worked in pairs to move the Romtec equipment 

and the full bags of composting material. Both were heavy and 

awkward to handle.

Results

 (continued)
Health Hazard Evaluation Report 2009-0100-3135 Page 5

Results

 (continued)

Figure 3. Bank of composting toilets on 

the trail.

Figure 4. Employee wearing hooded 

PAPR shoveling wood chips saturated 

with liquid out of a composting toilet.

Figure 5. Employee in Tyvek clothing 

bending over to shovel out the vault of 

a composting toilet.
Page 6 Health Hazard Evaluation Report 2009-0100-3135

Results

 (continued) Park employees are potentially exposed to heat stress. Temperatures 

were over 120°F in the sun (park thermometer) during the site visit; 

few areas of shade were available. Wearing PPE added to the heat 

burden. The crew took frequent breaks and rehydrated with water 

during these breaks.

We talked to employees about the hazards associated with wildlife 

that could live in and around the pit and composting toilets. Wildlife 

encountered in the past included black widow spiders, scorpions, and 

rodents. We saw a scorpion in the carrying tray of one of the Romtec 

units. Flies came out of the Romtec toilet when the lid was opened. 

We observed maggots all over the seat after the lid was left open 

during the cleaning process.

The employees expressed concern over potential exposures to HAV 

and HBV. The compost crew was vaccinated for both exposures, the 

rangers were vaccinated for HBV, and the trail crew was vaccinated for 

neither. All employees received tetanus vaccinations.

The employees explained that the trail crew provided first aid to park 

visitors and fellow employees when needed until additional staff 

arrived on the scene of an emergency. These emergencies included 

cuts and broken bones from falls. They expressed concern that they 

were not included in the vaccination program.

Air Sampling

Area ammonia and hydrogen sulfide concentrations are presented in 

Table 1. When we first opened the Romtec pit toilets, ammonia levels 

were high (50 ppm and 70 ppm); however, the levels quickly dropped 

when exposed to the ambient air. The ammonia levels probably did 

not exceed the NIOSH and ACGIH STEL of 35 ppm for a 15-

minute air sample, because these were instantaneous air samples. No 

hydrogen sulfide was detected at a limit of detection of 2 ppm.

No enteric bacteria were detected in the air samples (Table 2). 

Thermophilic actinomycetes, Gram-positive organisms found in soil 

and composting material, were detected in PBZ air samples from 

employees performing maintenance tasks on the Clivus and Phoenix 

composting toilets and in the area air sample collected below the 

composting toilets. No OELs have been established for either of these 

microbial agents.
Health Hazard Evaluation Report 2009-0100-3135 Page 7

Results

 (continued)

Table 1. Direct reading air samples for ammonia and hydrogen sulfide

Activity Ammonia (ppm)* Hydrogen Sulfide (ppm)

Opening Romtec 1 toilet seat lid 70 ND†

Opening Romtec 2 toilet seat lid 50 ND

Opening bottom bin of

 Clivus composting toilet

ND ND

Opening top of Phoenix

 toilet inside lower area

4 ND

*ppm—parts per million

†Not detected above the limit of detection (ammonia: 5 ppm; hydrogen sulfide: 2 ppm)

Table 2. Qualitative task-based and area air sampling results for enteric bacteria and 

thermophilic actinomycetes

Activity Sampling Time Enteric Bacteria Thermophilic 

Actinomycetes

Opening/shoveling out 

Romtec toilet

8:20 a.m.–9:41 a.m. ND* †

Opening/shoveling out 

Romtec toilet

8:21 a.m.–9:41 a.m. ND †

Cleaning out Romtec toilet at 

wastewater treatment plant

10:21 a.m.–11:41 a.m. ND †

Cleaning out Romtec toilet at 

wastewater treatment plant

10:21 a.m.–11:42 a.m. ND †

Maintenance/shoveling out 

Clivus toilet

8:20 a.m.–9:41 a.m. ND ND

Maintenance/shoveling out 

Phoenix toilet

8:20 a.m.–9:41 a.m. ND ND

Maintenance on Clivus toilet/

carrying and weighing bags

12:16 p.m.–2:57 p.m. ND ‡

Maintenance on Phoenix toilet/

carrying and weighing bags

12:16 p.m.–2:55 p.m. ND ‡

Area sample–shelter 12:18 p.m.–2:59 p.m. ND ‡

*ND—not detected

†Not analyzed (too wet)

‡Positive culture for bacteria
Page 8 Health Hazard Evaluation Report 2009-0100-3135

The park has approximately 4.5 million visitors a year, which 

makes the maintenance of the toilet facilities important for public 

health and environmental impact reasons [NPS 2010]. Composting 

toilets have been available commercially for about 40 years [U.S. 

EPA 1999]. Composting toilets treat pathogens to reduce the 

risk of infection and avoid environmental contamination. Four 

major types of human pathogenic organisms are found in human 

waste: (1) bacteria, (2) viruses, (3) protozoa, and (4) helminths 

(parasitic worms) [U.S. EPA 2003; Arthurson 2008]. The amount 

of pathogens present depends on the initial concentration and 

the amount of physical and biological decomposition that has 

occurred. The composting operation uses time, temperature, and 

aeration to facilitate the decomposition process [Arthurson 2008].

The moisture level in the composting toilets needed to be 

controlled for the composting process to produce usable compost. 

All but one of the composting toilets along the trail was functioning 

as designed. The malfunctioning toilet had a blocked leachate line, 

which allowed liquid to accumulate in the vault. This affected the 

composting process and made cleaning the vault more difficult. 

The composting crew had to add wood chips to the vault, which 

increased the weight and volume. Cleaning the vault occasionally 

required crew members to enter the vault up to their chest; 

therefore, this area met the NIOSH definition of a confined space.

The cleaning process for both types of toilets was labor intensive, 

requiring hand shoveling into either a backhoe loader or into 

bags, loading and unloading of pit toilets into a truck to take 

them to final cleaning, and manual carrying of the filled bags of 

waste to the mule station. Employees were potentially exposed to 

human waste when cleaning both types of toilets. Contact with 

the material on the tools used to remove the waste (shovels and/or 

metal bar) and with the outside of the bags were potential venues 

for exposure. Activities such as walking through wet material and 

keeping the toilets in service during the maintenance process 

also provided potential exposure, as did the flies landing on the 

employees after they had landed on the bags and raw sewage.

Our review of the scientific literature shows that the occupational 

exposure assessments for composting sewage sludge have focused 

on large municipal operations [Clark et al. 1983; Clark et al. 

1984; Johanning 1999; NIOSH 1999a,b,c; Schlosser et al. 2009]. 

Documented exposures for these activities included exposure to 

ammonia, thermophilic actinomycetes, Gram negative and Bacillus

Discussion
Health Hazard Evaluation Report 2009-0100-3135 Page 9

bacteria, endotoxin, and fungal genera (Cladosporium, Aspergillus, 

and Penicillium). We found potential exposures to ammonia and 

thermophilic actinomycetes in this evaluation. Enteric bacteria 

were not found in our task-based PBZ air sampling.

The PPE used by the employees was appropriate for the work that 

was being performed but may have increased the risk of heat stress. 

The written respiratory protection policy was comprehensive, 

including training, medical clearance, and fit testing in accordance 

with OSHA requirements under 29 CFR 1910.134. However, it did 

not specifically mention the use of the loose-fitting PAPR for the 

compost toilet maintenance work. The PAPRs had been purchased 

just before the NIOSH site visit. The written policy stated that an 

N100 filtering facepiece respirator should be worn while cleaning 

the composting toilets because of the potential for exposure to 

hantavirus, but CDC guidelines state that workers should use 

either a negative-pressure half-face air purifying respirator with 

N100 or P100 filters or a PAPR with high efficiency particulate 

filters [Mills et al. 2002]. We observed employees wearing only a 

facemask, not a respirator. Facemasks provided barrier protection 

against flies but are not considered respiratory protection.

While cleaning and maintaining toilets, employees had the 

potential for exposure to spiders, scorpions, and rodents/nesting 

material that could contain hantavirus. Employees also had a 

potential for exposure to HAV from handling the untreated waste 

in the pit toilets and to HBV from handling the trash (mostly 

feminine hygiene products) and from conducting first responder 

duties. More detailed information on the health issues associated 

with these exposures is provided in Appendix A.

Discussion

 (continued)
Page 10 Health Hazard Evaluation Report 2009-0100-3135

Employees who cleaned and serviced the pit and composting toilets 

were potentially exposed to a wide range of hazards including 

infectious agents, chemicals, heat, confined space, ergonomic 

stressors, and wildlife. We measured elevated ammonia levels 

when opening the Romtec toilets, but the levels rapidly dropped 

when diluted with outdoor air. We found that employees were 

exposed to airborne thermophilic actinomycetes, which can cause 

inflammatory lung disease, when cleaning out the composting 

toilets. The employees also had a potential for exposure to scorpion 

stings, spider bites, and airborne hantavirus from rodent nests/

feces. Potential exposure to bloodborne pathogens, such as HAV 

and HBV from handling untreated human waste and when 

performing first aid, was also a concern.

Conclusions

On the basis of our findings, we recommend the actions listed 

below to create a more healthful workplace. We encourage park 

management to use a labor-management health and safety committee 

or working group to discuss the recommendations in this report 

and develop an action plan. Those involved in the work can best 

set priorities and assess the feasibility of our recommendations for 

the specific situation at the park. Our recommendations are based 

on the hierarchy of controls approach (Appendix A: Occupational 

Exposure Limits and Health Effects). This approach groups actions 

by their likely effectiveness in reducing or removing hazards. In most 

cases, the preferred approach is to eliminate hazardous materials 

or processes and install engineering controls to reduce exposure 

or shield employees. Until such controls are in place, or if they are 

not effective or feasible, administrative measures and/or personal 

protective equipment may be needed.

Engineering Controls

Engineering controls reduce exposures to employees by removing the 

hazard from the process or placing a barrier between the hazard and 

the employee. Engineering controls are very effective at protecting 

employees without placing primary responsibility of implementation 

on the employee.

1. Develop a new method for emptying the Romtec toilets such 

as adding supports to the bottom of the Romtec container 

and using the backhoe to dump it into the landfill storage 

container. This will reduce exposures to untreated human 

waste and ergonomic hazards among the compost crew.

Recommendations
Health Hazard Evaluation Report 2009-0100-3135 Page 11

2. Replace or unblock the leachate lines for the trail toilets by 

clearing with a plumbing snake, using a pump to remove 

the liquid material, or installing a new evaporator system 

like the one used in the newer toilets. This will facilitate the 

composting process, reduce exposure to liquid waste, and 

minimize ergonomic hazards.

3. Design future toilet facilities with adequate space to allow 

the crew room to service them (manually remove waste) 

from the basement level.

Administrative Controls

Administrative controls are management-dictated work practices and 

policies to reduce or prevent exposures to workplace hazards. The 

effectiveness of administrative changes in work practices for controlling 

workplace hazards is dependent on management commitment and 

employee acceptance. Regular monitoring and reinforcement are 

necessary to ensure that control policies and procedures are not 

circumvented in the name of convenience or production.

1. Implement an administrative policy to open the Romtec toilets 

and have the employees move away from the area for a brief 

period (such as 1 minute) to reduce exposure to ammonia. 

Because this work is done outdoors, the ammonia levels are 

diluted quickly.

2. Develop a confined space policy for entering the composting 

toilet vault. It meets the NIOSH criterion for a confined space, 

and all relevant NIOSH guidelines for such confined spaces 

should be adhered to when entry is made into the composting 

toilet vault to pull down excess material (Appendix B). This 

includes using the checklist of considerations for entry, working 

in, and exiting confined spaces. Additional information can be 

found at http://www.cdc.gov/niosh/topics/confinedspace/.

3. Encourage employees to always wash their hands with soap and 

water, if available, or use hand sanitizer after removing gloves 

and before eating, drinking, or smoking.

4. Increase the number of times preventive maintenance on 

the toilet systems is done each year to prevent problems from 

developing and to reduce the amount of physical labor needed 

to clean the toilets [U.S. EPA 1999]. This allows problems such 

as blocked leachate lines to be identified and addressed in a 

timelier manner.

Recommendations

 (continued)
Page 12 Health Hazard Evaluation Report 2009-0100-3135 

5. Follow the recommendations for preventing heat stress and 

strain as described in a prior NIOSH HHE report, especially 

the sections concerning administrative controls and heat 

strain monitoring. This report can be found at http://www.

cdc.gov/niosh/hhe/reports/pdfs/1999-0321-2873.pdf.

6. Implement a voluntary HAV vaccination program for 

the trail crew and rangers. Include trail crews in annual 

bloodborne pathogen training required by OSHA if they 

are going to perform first aid activities, and offer HBV 

vaccinations to the trail crews.

7. Follow the recommendations outlined in Appendix A for 

dealing with scorpion or bee stings or spider bites. Establish 

standard operating procedures to deal with scorpion or 

bee stings or spider bites, and provide first aid kits with 

appropriate supplies so employees can treat these stings or 

bites when out on the trails. Insect repellants can be used to 

reduce exposures to flies and other pests.

8. Set up a policy to take toilets out of service during 

maintenance procedures to avoid direct exposure to 

untreated human waste.

9. Use a sunscreen with a minimum skin protection factor of 

15 to prevent exposure to ultraviolet radiation, which is a 

risk factor for sunburn and skin cancer.

Recommendations

 (continued)

Personal Protective Equipment

PPE is the least effective means for controlling employee exposures. 

Proper use of PPE requires a comprehensive program and calls 

for a high level of employee involvement and commitment to be 

effective. The use of PPE requires the choice of the appropriate 

equipment to reduce the hazard and the development of 

supporting programs such as training, change-out schedules, and 

medical assessment if needed. PPE should not be relied upon as 

the sole method for limiting employee exposures. Rather, PPE 

should be used until engineering and administrative controls can 

be demonstrated to be effective in limiting exposures to acceptable 

levels.

1. Continue to use the current PPE when maintaining and 

cleaning the toilets.

2. Update the written respiratory protection policy to include 

the PAPRs, and establish cleaning and maintenance 
Health Hazard Evaluation Report 2009-0100-3135 Page 13

procedures on their use including the regular replacement 

of the hoods if contaminated with untreated waste.

3. Provide training on the use of PAPRs and their cleaning 

and maintenance.

4. Use yellow rubber boots over the compost crew’s work boots 

to prevent the spread of contamination when work boots 

get wet.

5. Use protective gloves made of synthetic latex, vinyl, or 

nitrile. The latex gloves provide an effective barrier against 

biological agents, but because the use of natural latex poses 

a risk for developing latex allergy, other gloves should be 

used [NIOSH 1999d].

Recommendations

 (continued)

References

Arthurson V [ 2008]. Proper sanitization of sewage sludge: a 

critical issue for a sustainable society. Appl Environ Microbiol 

74(17):5267–5275.

Clark CS, Bjornson HS, Schwartz-Fulton J, Holland JW, Gartside 

PS [1984]. Biological health risks associated with the composting 

of wastewater treatment plant sludge. J Water Pollut Control Fed 

56(12):1269–1276.

Clark CS, Rylander R, Larsson l [1983]. Levels of Gram-negative 

bacteria, Aspergillus fumigatus, dust, and endotoxin at compost 

plants. Appl Environ Microbiol 45(5):1501–1505.

Dräger [2010]. Short-term measurements with Dräger-Tubes. 

[http://www.draeger.com/US/en_US/]. Date accessed: June 2011.

Johanning E [1999]. An overview of waste management in the 

United States and recent research activities about composting 

related occupational health risk. Schriftenr Ver Wasser Boden 

Lufthyg 104:127–140.

Mills JN, Corneli A, Young JC, Garrison LE, Khan AS, Ksiazek TG 

[2002]. Hantavirus pulmonary syndrome—United States: updated 

recommendations for risk reduction. MMWR 51(RR-9) 1–12.

NPS [2010]. NP reports: annual park visitation. [http://www.

nature.nps.gov/stats/viewReport.cfm]. Date accessed: June 2011.
Page 14 Health Hazard Evaluation Report 2009-0100-3135

NIOSH [1979]. Criteria for a recommended standard: Working in 

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

Education, and Welfare, Center for Disease Control, National 

Institute for Occupational Safety and Health, DHEW (NIOSH) 

Publication No. 80–106.

NIOSH [1999a]. Health hazard evaluation report: Central Maui 

Composting Facility Maui, Hawaii. By Burkhart JE. Morgantown, 

WV: U.S. Department of Health and Human Services, Centers 

for Disease Control and Prevention, National Institute for 

Occupational Safety and Health, NIOSH HETA No. 95-0203-2764.

NIOSH [1999b]. Health hazard evaluation report: City of 

Springfield, Department of Public Works Composting Facility, 

Springfield, Missouri. By Burkhart JE. Morgantown, WV: U.S. 

Department of Health and Human Services, Centers for Disease 

Control and Prevention, National Institute for Occupational Safety 

and Health, NIOSH HETA No. 95-0198-2765.

NIOSH [1999c]. Health hazard evaluation report: San Francisco 

Recreation and Parks Department, San Francisco, California. By 

Burkhart JE. Morgantown, WV: U.S. Department of Health and 

Human Services, Centers for Disease Control and Prevention, 

National Institute for Occupational Safety and Health, NIOSH 

HETA No. 95-0203-0252-2763.

NIOSH [1999d]. Latex allergy: a prevention guide. Cincinnati, 

OH: U.S. Department of Health and Human Services, Centers 

for Disease Control and Prevention, National Institute for 

Occupational Safety and Health, NIOSH Publication No. 98-113.

Schlosser O, Huyard A, Cartnick K, Yañez A, Catalán V, Quang 

ZD [2009]. Bioaerosol in composting facilities: occupational health 

risk assessment. .Water Environ Res 81(9):866–877.

U.S. EPA [1999]. Water efficiency technology fact sheet: 

composting toilets. Washington, DC: United States Environmental 

Protection Agency, Office of Water. EPA 832-F-99-066. [http://

www.epa.gov/owm/mtb/comp.pdf]. Date accessed: June 2011.

U.S. EPA [2003]. Environmental regulations and technology—

control of pathogens and vector attraction in sewage sludge. 

Washington, DC: Environmental Protection Agency, Office of 

Research and Development. EPA/625/R-92/013.

References

 (continued)
Health Hazard Evaluation Report 2009-0100-3135 Page 15

Appendix A: Occupational Exposure Limits and Health Effects

In evaluating the hazards posed by workplace exposures, NIOSH investigators use both mandatory (legally 

enforceable) and recommended OELs for chemical, physical, and biological agents as a guide for making 

recommendations. OELs have been developed by federal agencies and safety and health organizations to 

prevent the occurrence of adverse health effects from workplace exposures. Generally, OELs suggest levels 

of exposure that most employees may be exposed to for up to 10 hours per day, 40 hours per week, for a 

working lifetime, without experiencing adverse health effects. However, not all employees will be protected 

from adverse health effects even if their exposures are maintained below these levels. A small percentage 

may experience adverse health effects because of individual susceptibility, a preexisting medical condition, 

and/or hypersensitivity (allergy). In addition, some hazardous substances may act in combination with 

other workplace exposures, the general environment, or with medications or personal habits of the 

employee to produce adverse health effects even if the occupational exposures are controlled at the level set 

by the exposure limit. Also, some substances can be absorbed by direct contact with the skin and mucous 

membranes in addition to being inhaled, which contributes to the individual’s overall exposure.

Most OELs are expressed as a TWA exposure. A TWA refers to the average exposure during a normal 8- 

to 10-hour workday. Some chemical substances and physical agents have recommended STEL or ceiling 

values where adverse health effects are caused by exposures over a short period. Unless otherwise noted, 

the STEL is a 15-minute TWA exposure that should not be exceeded at any time during a workday, and 

the CL is an exposure that should not be exceeded at any time.

In the United States, OELs have been established by federal agencies, professional organizations, state 

and local governments, and other entities. Some OELs are legally enforceable limits, while others are 

recommendations. The U.S. Department of Labor OSHA PELs (29 CFR 1910 [general industry]; 29 

CFR 1926 [construction industry]; and 29 CFR 1917 [maritime industry]) are legal limits enforceable 

in workplaces covered under the Occupational Safety and Health Act of 1970. NIOSH RELs are 

recommendations based on a critical review of the scientific and technical information available on a 

given hazard and the adequacy of methods to identify and control the hazard. NIOSH RELs can be 

found in the NIOSH Pocket Guide to Chemical Hazards [NIOSH 2005]. NIOSH also recommends different 

types of risk management practices (e.g., engineering controls, safe work practices, employee education/

training, personal protective equipment, and exposure and medical monitoring) to minimize the risk of 

exposure and adverse health effects from these hazards. Other OELs that are commonly used and cited 

in the United States include the TLVs recommended by ACGIH, a professional organization, and the 

WEELs recommended by the American Industrial Hygiene Association, another professional organization. 

The TLVs and WEELs are developed by committee members of these associations from a review of the 

published, peer-reviewed literature. They are not consensus standards. ACGIH TLVs are considered 

voluntary exposure guidelines for use by industrial hygienists and others trained in this discipline “to assist 

in the control of health hazards” [ACGIH 2011]. WEELs have been established for some chemicals “when 

no other legal or authoritative limits exist” [AIHA 2010].

Outside the United States, OELs have been established by various agencies and organizations and include 

both legal and recommended limits. Since 2006, the Berufsgenossenschaftliches Institut für Arbeitsschutz 

(German Institute for Occupational Safety and Health) has maintained a database of international OELs 
Page 16 Health Hazard Evaluation Report 2009-0100-3135

from European Union member states, Canada (Québec), Japan, Switzerland, and the United States. The 

database, available at http://www.dguv.de/ifa/en/gestis/limit_values/index.jsp, contains international 

limits for over 1500 hazardous substances and is updated periodically. 

Employers should understand that not all hazardous chemicals have specific OSHA PELs, and for some 

agents the legally enforceable and recommended limits may not reflect current health-based information. 

However, an employer is still required by OSHA to protect its employees from hazards even in the absence 

of a specific OSHA PEL. OSHA requires an employer to furnish employees a place of employment free 

from recognized hazards that cause or are likely to cause death or serious physical harm [Occupational 

Safety and Health Act of 1970 (Public Law 91–596, sec. 5(a)(1))]. Thus, NIOSH investigators encourage 

employers to make use of other OELs when making risk assessments and risk management decisions to 

best protect the health of their employees. NIOSH investigators also encourage the use of the traditional 

hierarchy of controls approach to eliminate or minimize identified workplace hazards. This includes, in 

order of preference, the use of (1) substitution or elimination of the hazardous agent, (2) engineering 

controls (e.g., local exhaust ventilation, process enclosure, dilution ventilation), (3) administrative controls 

(e.g., limiting time of exposure, employee training, work practice changes, medical surveillance), and (4) 

personal protective equipment (e.g., respiratory protection, gloves, eye protection, hearing protection). 

Control banding, a qualitative risk assessment and risk management tool, is a complementary approach 

to protecting employee health that focuses resources on exposure controls by describing how a risk 

needs to be managed. Information on control banding is available at http://www.cdc.gov/niosh/topics/

ctrlbanding/. This approach can be applied in situations where OELs have not been established or can be 

used to supplement the OELs, when available.

Ammonia

Ammonia is a colorless, strongly alkaline, extremely soluble gas with a characteristic pungent odor. It is 

a severe irritant of the eyes, respiratory tract, and skin. Repeated exposure to ammonia vapor may cause 

chronic irritation of the eyes and upper respiratory tract [ATSDR 2004]. The NIOSH REL for ammonia 

is 25 ppm for a 10-hour TWA. The NIOSH STEL for ammonia is 35 ppm. The ACGIH has established a 

TLV of 25 ppm as an 8-hour TWA and a STEL of 35 ppm. The OSHA PEL for ammonia is 50 ppm for an 

8-hour TWA.

Scorpions and Spiders

Scorpions mostly live in dry, desert areas and are active at night. They may be hiding under rocks, wood, 

or anything else lying on the ground. Some species may also burrow into the ground. To prevent scorpion 

stings, employees can wear long sleeves, pants, and leather gloves when practical. It is important to shake 

out shoes or clothing before donning. Additional information on first aid can be found at http://www.

cdc.gov/niosh/topics/insects/.

Appendix A: Occupational Exposure Limits and Health Effects

 (continued)
Health Hazard Evaluation Report 2009-0100-3135 Page 17

Black widow spiders are commonly found in the southern and western areas of the United States. They are 

identified by the pattern of red coloration on the underside of their abdomen. They live in outdoor toilets 

where flies are plentiful or in undisturbed places such as under eaves and fences. A bite from a black 

widow can be distinguished by the two puncture marks it makes in the skin. The venom is a neurotoxin 

that produces pain at the bite area and then spreads to the chest, abdomen, or the entire body. Employees 

should inspect clothing, shoes, towels, or equipment before use, and wear clothing including long-sleeved 

shirt and long pants, hat, gloves, and boots when handling stacked or undisturbed piles of materials. 

Additional information on first aid can be found at http://www.cdc.gov/niosh/topics/spiders/.

Hantavirus Pulmonary Syndrome

Hantavirus pulmonary syndrome is a deadly disease transmitted by infected rodents through urine, 

droppings, or saliva [Mills et al. 2002]. In the southwestern United States, it is carried by deer mice and 

cotton and rice rats. Humans can contract the disease when they breathe in aerosolized virus. Rodent 

control in and around the workplace remains the primary strategy for preventing hantavirus infection. 

Additional information is available in the CDC documents, “Facts about Hantaviruses: What You Need 

to Know to Prevent the Disease Hantavirus Pulmonary Syndrome (HPS)” at http://www.cdc.gov/ncidod/

dvrd/spb/mnpages/HPS_Brochure.pdf and “Hantavirus Pulmonary Syndrome (HPS): What You Need to 

Know” at http://www.cdc.gov/ncidod/diseases/hanta/hps/noframes/HPS_WhatYouNeedToKnow.pdf.

Hepatitis A

Hepatitis A is a contagious liver disease that results from infection with HAV. HAV is spread primarily 

by fecal/oral routes (often resulting from inadequate hand washing) and may be spread via contaminated 

food or water. Depending on environmental conditions, HAV can be stable in the environment for at least 

30 days [McCaustland et al. 1982]. Since the 1960s, most hepatitis A cases have in occurred in the western 

and southwestern United States [Fiore et al. 2006]. Additional information on hepatitis A can be found at 

http://www.cdc.gov/hepatitis/A/PDFs/HepAGeneralFactSheet.pdf.

The data for the need for vaccinations for wastewater employees for HAV are mixed [Tooher et al. 2005]. 

Data from serologic studies conducted in Europe indicate that employees who had been exposed to sewage 

had a possible elevated risk for HAV infection [Poole and Shakespeare 1993; Lerman et al. 1999; Glas et 

al. 2001]. In published reports of three serologic surveys conducted among U.S. wastewater employees and 

appropriate comparison populations, no substantial or consistent increase in the prevalence of anti-HAV 

was identified among the employees [Trout et al. 2000; Weldon et al. 2000; Venczel 2003]. No cases of 

occupational HAV transmission among wastewater employees have been reported in the literature for the 

United States; however, there are isolated case reports for other countries including Canada [De Serres 

and Laliberté 1997]. The studies do not provide information about whether or not the employees were 

exposed to treated or untreated human waste.

Appendix A: Occupational Exposure Limits and Health Effects

 (continued)
Page 18 Health Hazard Evaluation Report 2009-0100-3135

Hepatitis B

Hepatitis B is a contagious liver disease caused by HBV. The disease can range in severity from a mild 

illness lasting a few weeks to a serious, lifelong illness. Hepatitis B is usually spread when blood, semen, or 

another body fluid from a person infected with the hepatitis B virus enters the body of someone who is 

not infected. This can happen through sexual contact with an infected person or sharing needles, syringes, 

or other drug-injection equipment. Hepatitis B can also be passed from an infected mother to her baby at 

birth. HBV can survive for at least 7 days outside the human body [Bond et al. 1981]. Vaccination is the 

best way to prevent hepatitis B. Additional information on hepatitis B can be found at http://www.cdc.

gov/hepatitis/HBV/PDFs/HepBGeneralFactSheet.pdf.

References

ACGIH [2011]. 2010 TLVs® and BEIs®: threshold limit values for chemical substances and physical 

agents and biological exposure indices. Cincinnati, OH: American Conference of Governmental 

Industrial Hygienists.

AIHA [2010]. AIHA 2010 Emergency response planning guidelines (ERPG) & workplace environmental 

exposure levels (WEEL) handbook. Fairfax, VA: American Industrial Hygiene Association.

ATSDR [2004] Toxicological profile for ammonia. [http://www.atsdr.cdc.gov/toxprofiles/tp126.pdf]. Date 

accessed: June 2011.

Bond WW, Favero MS, Petersen NJ, Gravelle CR, Ebert JW, Maynard JE [1981]. Survival of hepatitis B 

virus after drying and storage for one week. Lancet 1(8219):550–551.

CFR. Code of Federal Regulations. Washington, DC: U.S. Government Printing Office, Office of the 

Federal Register.

De Serres G, Laliberté D [1997]. Hepatitis A among workers from a wastewater treatment plant during a 

small community outbreak. Occup Environ Med 54(1):60–62.

Glas C, Hotz P, Steffen R [2001]. Hepatitis A in workers exposed to sewage: a systematic review. Occup 

Environ Med 58(12):762–768.

Lerman Y, Chodick G, Aloni H, Ribak J, Ashkenazi S [1999]. Occupations at increased risk of hepatitis A: 

a 2-year nationwide historical prospective study. Am J Epidemiol 150(3):312–320.

McCaustland KA, Bond WW, Bradley DW, Ebert JW, Maynard JE [1982] Survival of hepatitis A virus in 

feces after drying and storage for 1 month. J Clin Microbiol 16(5):957–958.

Appendix A: Occupational Exposure Limits and Health Effects

 (continued)
Health Hazard Evaluation Report 2009-0100-3135 Page 19

Mills JN, Corneli A, Young JC, Garrison LE, Khan AS, Ksiazek TG [2002]. Hantavirus pulmonary 

syndrome – United States: updated recommendations for risk reduction. MMWR 51(RR-9):1–12.

NIOSH [2005]. NIOSH pocket guide to chemical hazards. Cincinnati, OH: U.S. Department of Health 

and Human Services, Centers for Disease Control and Prevention, National Institute for Occupational 

Safety and Health, DHHS (NIOSH) Publication No. 2005-149. [http://www.cdc.gov/niosh/npg/]. Date 

accessed: June 2011.

Poole CJ, Shakespeare AT [1993]. Should sewage workers and carers for people with learning disabilities be 

vaccinated for hepatitis A? Br Med J 306(6885):1102.

Tooher R, Griffin T, Shute E, Maddern G [2005]. Vaccinations for waste-handling workers. A review of 

the literature. Waste Manag Res 23(1):79–86.

Trout D, Mueller C, Venczel L, Krake A [2000]. Evaluation of occupational transmission of hepatitis A 

virus among wastewater workers. J Occup Environ Med 42(1):83–87.

Venczel L, Brown S, Frumkin H, Simmonds-Diaz J, Deitchman S, Bell BP [2003]. Prevalence of hepatitis A 

virus infection among sewage workers in Georgia. Am J Industrial Med 43(2):172–178.

Weldon M, VanEgdom MJ, Hendricks KA, Regner G, Bell BP, Sehulster LM [2000]. Prevalence of 

antibody to hepatitis A virus in drinking water workers and wastewater workers in Texas from 1996 to 

1997. J Occup Environ Med 42(8):821–826.

Appendix A: Occupational Exposure Limits and Health Effects

 (continued)
Page 20 Health Hazard Evaluation Report 2009-0100-3135

Appendix B: Confined Space Entry Requirements

Composting toilet vaults such as those described in this report meet NIOSH criteria for a confined space. 

NIOSH defines a confined space as “an area which by design has limited openings for entry and exit, 

unfavorable natural ventilation which could contain (or produce) dangerous air contaminant, and which 

is not intended for continuous employee occupancy” [NIOSH 1979]. The NIOSH criteria for working 

in confined spaces further classify confined spaces on the basis of the atmospheric characteristics such as 

oxygen level, flammability, and toxicity. As shown in Table B1, if any of the hazards present a situation 

that is IDLH, the confined space is designated Class A. A Class B confined space has the potential for 

causing injury and/or illness, but is not an IDLH atmosphere. A Class C confined space is one in which 

the hazard potential would not require any special modification of the work procedure. Table B2 lists the 

confined space program elements that are recommended (or must be considered by a qualified person, as 

defined by the criteria) before entering and during work within confined spaces on the basis of established 

hazard classification [29 CFR 1910.146]. The work in the composting toilets would be considered a Class C 

confined space.

Table B1. Confined space classification table [NIOSH 1979]

Parameters Class A Class B Class C

Characteristics IDLH* – rescue 

procedures require the 

entry of more than one 

individual fully equipped 

with life support equipment 

– maintenance of 

communication requires 

an additional standby 

person stationed within the 

confined space

Dangerous, but not 

immediately life 

threatening – rescue 

procedures require the 

entry of no more than one 

individual fully equipped 

with life support equipment 

– indirect visual or auditory 

communication with 

worker

Potential hazard – requires 

no modification of work 

procedures – standard 

rescue procedures – 

direct communication with 

workers, from outside the 

confined space

Oxygen 16% or less (122 mm Hg) 

or greater than 25% (190 

mm HG)†

16.1% to 19.4% (122 – 

147 mm Hg) or 21.5% to 

25% (163 – 190 mm Hg)

19.5% – 21.4% 

(148 – 163 mm Hg)

Flammability 

Characteristics

20% or greater of LFL‡ 10% – 19% LFL 10% LFL or less

Toxicity IDLH Greater than 

contamination level, 

referenced in 29 CFR Part 

1910 Sub Part Z – less 

than IDLH

Less than contamination 

level referenced in 29 CFR 

Part 1910 Sub Part Z

*Immediately dangerous to life or health

†On the basis of a total atmospheric pressure of 760 millimeters of mercury (mm Hg) at sea level

‡Lower flammable limit
Health Hazard Evaluation Report 2009-0100-3135 Page 21

Appendix B: Confined Space Entry Requirements

 (continued)

Table B2. NIOSH checklist of considerations for entry, working in, and exiting confined spaces 

[NIOSH 1979]

 Item Class A Class B Class C

1. Permit X* X X

2. Atmospheric testing X X X

3. Monitoring X O† O

4. Medical surveillance X X O

5. Training of personnel X X X

6. Labeling and posting X X X

7. Preparation

 Isolate/lockout/tag X X O

 Purge and ventilate X X O

 Cleaning processes O O O

 Requirements for special

 equipment/tools

X X O

8. Procedures

 Initial plan X X X

 Standby X X O

 Communications/observation X X X

 Rescue X X X

 Work X X X

9. Safety equipment and clothing

 Head protection O O O

 Hearing protection O O O

 Hand protection O O O

 Foot protection O O O

 Body protection O O O

 Respiratory protection O O

 Safety belts X X X

 Life lines, harness X O

10. Rescue equipment X X X

11. Record keeping/exposure X X

*X—Indicates requirement

†O—Indicates determination by the qualified person
Page 22 Health Hazard Evaluation Report 2009-0100-3135

Appendix B: Confined Space Entry Requirements

 (continued)

References

CFR. Code of Federal Regulations. Washington, DC: U.S. Government Printing Office, Federal Register.

NIOSH [1979]. Criteria for a recommended standard: working in confined spaces. Cincinnati, OH: 

U.S. Department of Health, Education, and Welfare, Center for Disease Control, National Institute for 

Occupational Safety and Health, DHEW (NIOSH).
Health Hazard Evaluation Report 2009-0100-3135 Page 23

Acknowledgments and

Availability of Report The Hazard Evaluations 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 

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

Health and Human Services, following a written request from any 

employer or authorized representative of employees, to determine 

whether any substance normally found in the place of employment 

has potentially toxic effects in such concentrations as used or found. 

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.

The findings and conclusions in this report are those of the 

authors and do not necessarily represent the views of NIOSH. 

Mention of any company or product does not constitute 

endorsement by NIOSH. In addition, citations to websites 

external to NIOSH do no constitute NIOSH endorsement of 

the sponsoring organizations or their programs or products. 

Furthermore, NIOSH is not responsible for the content of these 

websites. All Web addresses referenced in this document were 

accessible as of the publication date.

This report was prepared by Nancy Clark Burton and Chad Dowell 

of HETAB, Division of Surveillance, Hazard Evaluations and 

Field Studies. Analytical support was provided by Microbiology 

Specialists Inc., Houston, Texas. Health communication assistance 

was provided by Stefanie Evans. Editorial assistance was provided by 

Ellen Galloway. Desktop publishing was performed by Greg Hartle.

Copies of this report have been sent to employee and management 

representatives at the federal agency, the state health department, 

and the Occupational Safety and Health Administration Regional 

Office. This report is not copyrighted and may be freely reproduced. 

The report may be viewed and printed at 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.
Below is a recommended citation for this report:

NIOSH [2011]. Health hazard evaluation report: evaluation of exposures 

associated with cleaning and maintaining composting toilets – Arizona. By 

Burton NC, Dowell C. Cincinnati, OH: U.S. Department of Health and Human 

Services, Centers for Disease Control and Prevention, National Institute for 

Occupational Safety and Health, NIOSH HETA No. 2009-0100-3135.

To receive NIOSH documents or information about 

occupational safety and health topics, contact NIOSH at:

1-800-CDC-INFO (1-800-232-4636)

TTY: 1-888-232-6348

E-mail: cdcinfo@cdc.gov

or visit the NIOSH web site at: www.cdc.gov/niosh.

For a monthly update on news at NIOSH, subscribe to 

NIOSH eNews by visiting www.cdc.gov/niosh/eNews.

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Safety and Health