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234 Waste Management Practices: Municipal, Hazardous, and Industrial
composting piles and vessels tend to be monitored and controlled for temperature, moisture, and
aeration while storage and curing piles may be neglected (Rynk, 2000).

8.8.9 LITTER
Although not a hazard per se, litter from the facility is an aesthetic problem and a possible source
of complaints from nearby residents. Litter originates from MSW brought into the facility, plastic,
and paper blowing from piles, and rejects (such as plastic) blowing away during screening. Litter
can be controlled by (Wirth, 1989: U.S. EPA, 1994):

● Requiring loads of incoming material to be covered
● Using moveable fencing or chain link fences along the site perimeter as windbreaks and
to facilitate collection of litter
● Enclosing receiving, processing, and finishing operations
● Collecting litter as soon as possible before it becomes scattered off-site
● Removing plastic bags before windrowing
● Collecting leaves and woody materials in paper bags, plastic bins, or in bulk

8.9 OCCUPATIONAL HEALTH AND SAFETY CONCERNS DURING
COMPOSTING
Potential health and safety problems at composting facilities include accidents with heavy equip-
ment, exposure to excessive noise, and exposure to bioaerosols and potential toxic chemicals.
Proper siting, design, and operation of the facility and adequate worker training and education can
minimize these problems.

8.9.1 BIOAEROSOLS
A variety of biological aerosols (bioaerosols) can be generated during composting. Bioaerosols are
suspensions of particles in the air consisting partially or wholly of microorganisms. These aggre-
gates can remain suspended in the air for long periods, retaining their viability (infectious nature).
The bioaerosols of concern during composting include actinomycetes, bacteria, viruses, molds, and
fungi. Aspergillus fumigatus is a common fungus that is naturally present in decaying organic mat-
ter. The fungal spores can be inhaled or enter the body through cuts and abrasions in the skin. The
fungus is not considered a hazard to healthy individuals (U.S. EPA, 1994). A. fumigatus is readily
dispersed from dry compost piles during and after mechanical turning. The levels of A. fumigatus
decrease rapidly a short distance from the pile or a short time after composting activity ceases
(Epstein and Epstein, 1989).
Endotoxins are another concern at composting facilities. Endotoxins are toxins produced within
a microbial cell and released upon cell destruction. These compounds are carried by airborne dust
particles. The level of endotoxins in the air at one yard waste composting facility ranged from 0.001
3
to 0.014 mg/m (Roderique and Roderique, 1990).
Because bioaerosols and endotoxins are both carried as dust, dust should be controlled at all
times at the facility. Steps to minimize dust generation may include (U.S. EPA, 1994):

● Keeping compost piles and feedstock moist.
● Moistening compost during the final pile teardown and before being loaded onto vehi-
cles, taking care not to over-wet the material (which can produce leachate or runoff).
● If the facility is enclosed, proper ventilation is required via engineering controls such as
collection hoods, negative air pressure at dust generation points, and the use of baghouse
filtration.