What should employers do to prevent
work-related illness?
To protect workers who have direct contact
with Class B biosolids and thus are likely to
have an exposure to pathogens, employers should
provide a basic level of protection, including
appropriate measures from those listed below.
While the measures are worded to refer to
Class B biosolids, most also apply to tasks involving
contact with sewage, untreated or partially
treated sludge, or substandard biosolids.
Provide basic hygiene
recommendations for workers.
Basic hygiene precautions are important for
workers handling biosolids. The following list,
originally developed by EPA, provides a good
set of hygiene recommendations.
1. Wash hands thoroughly with soap and
water after contact with biosolids.
2. Avoid touching face, mouth, eyes, nose,
genitalia, or open sores and cuts while
working with biosolids.
3. Wash your hands before you eat, drink,
or smoke and before and after using the
bathroom.
4. Eat in designated areas away from
biosolids-handling activities.
5. Do not smoke or chew tobacco or gum
while working with biosolids.
6. Use barriers between skin and surfaces
exposed to biosolids.
7. Remove excess biosolids from footgear
prior to entering a vehicle or a building.
8. Keep wounds covered with clean, dry
bandages.
9. Thoroughly but gently flush eyes with
water if biosolids contact eyes.
10. Change into clean work clothing on a
daily basis and reserve footgear for use at
worksite or during biosolids transport.
11. Do not wear work clothes home or outside
the work environment.
12. Use gloves to prevent skin abrasion.
In addition, NIOSH recommends the following
steps to provide a more comprehensive set
of precautions for use by employers and
employees:
Provide appropriate protective equipment, hygiene stations,
and training.
Personal Protective Equipment (PPE).—
Appropriate PPE should be provided for all
workers likely to have exposure to biosolids.
The choices of PPE include goggles, splash-proof
face shields, respirators, liquid-repellent coveralls,
and gloves. Face shields should be made
available for all jobs in which there is a potential
for exposure to spray or high-pressure leaks,
or aerosolized biosolids during land application.
Management and employee representatives
should work together to determine which job
duties are likely to result in this type of exposure,
to conduct appropriate on-site monitoring,
and to determine which type of PPE is
needed in conjunction with a qualified safety
and health professional. If respirators are needed,
a comprehensive program would include respirator
fit-testing and training or retraining.
Hygiene and Sanitation.---Hand-washing stations
with clean water and mild soap should
be readily available whenever contact with
biosolids occurs. In the case of workers in the
field, portable sanitation equipment, including
clean water and soap, should be provided. Cabs
should be wiped down and cleaned of residual
mud (or settled dust) frequently to reduce potential
for exposure to biosolids.
Training.---Periodic training on standard hygiene
practices for biosolids workers should be
conducted by qualified safety and health professionals
to cover issues such as the following:
• Frequent and routine hand washing (the
most valuable safeguard in preventing infection
by agents present in biosolids), especially
before eating or smoking
• The proper use of appropriate PPE, such
as coveralls, boots, gloves, goggles, respirators,
and face shields
• The removal of contaminated PPE and the
use of available on-site showers, lockers,
and laundry services
• Proper storage, cleaning, or disposal of
contaminated PPE
• Instructions that work clothes and boots
should not be worn home or outside the
immediate work environment
• Prohibition of eating, drinking, or smoking
while working in or around biosolids
• Procedures for controlling exposures to
chemical agents that may be in biosolids
Reporting. ---Workers should be trained to
report potentially work-related illnesses or symptoms
to the appropriate supervisory or health
care staff. This may aid in the early detection of
work-relat ed health effects.
Immunizations.---Ensure that all employees
are up-to-date on tetanus-diphtheria immunizations,
since employees are at risk of soil-contaminated injuries.
Current CDC recommendations do not support
hepatitis A vaccination for sewage workers.
Extend good environmental practices to prevent and
minimize occupational exposures.
• Where feasible, substituting ClassAbiosolids
could reduce the pathogen exposure risks
during land application compared to applying
Class B biosolids. Feasibility may
be affected by local customer preferences,
since the two types of biosolids
vary in the nutrient value they provide to
end-users.
• Monitor the source material coming from
the wastewater treatment facility. Check
monitoring results to assure they meet specified
Class B or Class A standards prior to
land application operations.
• Monitor stored biosolids prior to application
to assure that the biosolids are properly
stabilized and that unacceptable
regrowth or cross-contamination from
substandard material has not occurred.
• Where local conditions permit, inject
biosolids below the soil or incorporate
(thoroughly mix) into tilled soil. This will
minimize post-application worker contact
with applied biosolids and prevent
resuspension into the air during periods of
dryness.
• On windy days, avoid spreading or disturbing
dry biosolids (e.g., compost) that
would create dust.
• On windy days, avoid spreading biosolids
by high-pressure spray.
• Avoid unnecessary mechanical disturbance
and contact with land-applied Class B
biosolids during the period when public
access is restricted.
• Equip heavy equipment used at storage
and application facilities with sealed,
positive-pressure, air-conditioned cabs that
contain filtered air-recirculation units.
• Monitor worker exposures when adjusting
precautions to address site-specific
issues.
Page Two
Page Three
Do we know these pathogens can cause
disease?
Yes, the association between poor hygiene, raw
sewage, and infectious disease is well established.
Most of the pathogenic bacteria, viruses,
and parasites in biosolids are enteric, which
employees reported repeated episodes of
gastrointestinal illness after working with
the biosolids, either at the treatment plant
or during land application.
• NIOSH observed among workers an inconsistent
awareness, provision, and use
of protective equipment and hygiene practices
appropriate for handling Class B
biosolids (or biosolids that do not comply
with EPA standards).
• NIOSH collected bulk samples from different
locations within the biosolids storage
site and found measurable concentrations
of fecal coliforms. Fecal coliforms
are used as an indicator for the presence
of other enteric microorganisms. Enteric
bacteria were detected in air samples collected
at the land application site.
• The local department of environmental
services recently informed NIOSH that
biosolids applied at this site intermittently
exceeded (by up to 4.5 times) the EPA
fecal coliform upper limit for Class B
biosolids prior to the NIOSH survey.
• The substandard biosolids were applied at
the agricultural site before the monitoring
results were received from the laboratory.
EPA reports that high-pressure spray applications
may result in some aerosolization of
pathogens and that application or incorporation
of dewatered biosolids may cause very
localized fine particulate/dusty conditions. Also,
farm workers may be exposed to biosolids after
application and during the restricted period. Ancillary
workers (for example, laborers hired to
clean trucks that were used to haul biosolids)
can be exposed to biosolids. Exposures to substandard
biosolids can occur when these materials
are loaded and hauled to approved landfills
or incinerators for disposal.
Additional study of worker exposures to pathogens
and other toxics possibly present in
Class B biosolids is needed. This will reduce
scientific uncertainty about these issues and allow
further refinement of worker precautions.
What should employers do to prevent
work-related illness?
To protect workers who have direct contact
with Class B biosolids and thus are likely to
have an exposure to pathogens, employers should
provide a basic level of protection, including
appropriate measures from those listed below.
While the measures are worded to refer to
Class B biosolids, most also apply to tasks involving
contact with sewage, untreated or partially
treated sludge, or substandard biosolids.
Page One