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Potential Health Hazards:
- A wide range of adhesives and coating agents are
used in finishing wood products. Many of these are
hazardous to the health of employees. Chemicals
can enter the body in three ways: inhalation
(breathing), ingestion (eating), or contact with the
skin. The skin readily absorbs many chemicals,
such as solvents, allowing them to enter the bloodstream.
Woodworkers generally are exposed to
chemicals through inhalation and contact with the
skin.
Both nitrocellulose topcoats (lacquers) and acid-catalyzed
coatings (conversion varnishes) contain
solvents that are toxic to humans. The solvents
most commonly used in these coatings include
toluene, xylenes, methyl ethyl ketone (MEK),
methyl isobutyl ketone (MIBK), and methanol. The
acid-catalyzed coatings contain formaldehyde. All
of these solvents have short-term effects such as
irritation of the eyes, nose, and throat, and headaches,
dizziness, confusion, fatigue, and nausea.
The longer-term effects include reproductive
problems, central nervous system disorders, and
damage to the lungs, liver, and kidneys. Toluene
exposure increases the risk of miscarriage. Developmental
effects have been noted in children born
to mothers who were exposed to toluene and xylenes. Studies have shown that formaldehyde can
cause lung and nasal cancer.
Many of the adhesives used in finishing wood
products also contain toxic chemicals. The most
hazardous are the solvent-based, epoxy resin, and urea-formaldehyde resin adhesives. Many of the
solvents used in the coating agents are used in the
adhesives. The epoxy resin adhesives are particularly
toxic. Methylene chloride, which has been
shown to cause cancer in laboratory animals, is
often the base for these adhesives. Some of the
components of the epoxy resins may also be cancer-causing.
Epoxy resin adhesives can also cause
dermatitis and a sensitization reaction.
Possible Solutions:
Engineering Controls
- Use automated systems for
applying coatings and adhesives when feasible. Ventilate automated
systems.
- Substitute the traditional solvent-based coatings
and adhesives with coatings and adhesives that
are less toxic. Hot melt, heat seal, aqueous-based,
and polyvinyl acetate adhesives are good,
less-toxic alternatives to solvent-based adhesives.
Higher-solids nitrocellulose, aqueous-based, ultraviolet-cured, and polyester/polyurethane
coatings also are less toxic than are solvent-based
coatings.
- Provide adequate local exhaust ventilation for
all coating and gluing processes. This includes
manual spray, rolling, and brushing operations,
automated coating processes, and dip coating. Perform manual spray operations in
a spray booth or a separate, ventilated spray
area. Ventilate dip coating should be ventilated with an
enclosure or capture hood. Consult the OSHA
standard on dip coating (open surface tanks), 1910.108, for detailed requirements on
dipping operations.
- The OSHA standard for spray finishing operations,
29 CFR 1910.107, provides detailed
requirements for the design and construction of
spray booths and rooms, air filters, velocity and
air flow requirements, and the (make-up) air
supplied to the booth. It is important to maintain
the proper air flow in a spray booth. Excessive
air pressure decreases the efficiency of the
operation, wastes material, and may cause a
backlash of vapors and overspray into adjacent
work areas. Dirty air filters can decrease the air
flow in the booth. Clean and replace filters as needed. Although these provisions
are designed to prevent the occurrence of a
fire or explosion in spray finishing operations,
they also assist in protecting workers from the
health hazards of the chemicals used in the
operation by removing the chemicals from the
atmosphere.
- Employers shall provide employees with effective information
and training on hazardous chemicals. 1910.1200(h)(1)
- Chemical
related images.
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Employees must not be exposed to airborne
concentration of toxic dusts, fumes, vapors, mists or gases that exceed
the threshold limit values set forth by 1910.1000.
1910.265(c)(17)(i)
Employees must be protected from harmful exposure to toxic materials. Where
necessary, employees are required to wear protective equipment that will
provide adequate protection against harmful
exposure. 1910.265(c)(17)(ii)
Open surface tank operations need to conform to the requirements of 1910.94(d).
1910.265(c)(17)(iii)
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