Potential Health Hazards:
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A wide range of adhesives and coating agents are
used in finishing wood products. Many of these are
hazardous to the employees' health.
Chemicals
can enter the body in three ways: through 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, 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.
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, often is the base for these adhesives. Some of the
components of the epoxy resins also may be cancer-causing.
Epoxy resin adhesives also can cause
dermatitis and a sensitization reaction.
Potential Safety Hazards:
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In addition to the health hazards posed by the
chemicals used in finishing operations, many of the
solvents, lacquers, varnishes, and coatings used in
these operations are extremely flammable. These
materials can pose significant fire and explosion
hazards if used in large quantities, in unventilated
or enclosed areas, or in processes such as spray
finishing operations that can lead to significant
airborne concentrations of the material.
Possible Solutions:
Engineering Controls
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When feasible, use automated systems for
applying coatings and adhesives. Automated
systems should be ventilated.
-
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 solvent-based
coatings.
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Provide adequate local exhaust ventilation for
all coating and gluing processes. This includes
manual spraying, rolling, and brushing operations,
automated coating processes, and dip coating.
Manual spray operations should be performed in
a spray booth or a separate, ventilated spray
area. Dip coating should be ventilated with an
enclosure or capture hood. Consult the OSHA
standard on dip coating (open surface tanks), 1910.122-126, for detailed requirements on
dipping operations.
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The OSHA standard for spray finishing operations,
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. Ensure that filters are cleaned
and replaced 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.
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Employers shall provide employees with effective information
and training on hazardous chemicals. 1910.1200(h)(1)
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Controls designed to prevent fire and explosion
resulting from the use of flammable and combustible
materials in woodworking operations are discussed in the Fire
and Explosion section of this eTool. The controls discussed in this section generally
are
also applicable to finishing operations. |
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www.osha.gov
Finishing operations pose a wide range of health
and safety hazards due to the volume and physical
properties of the chemicals involved. A complete
discussion of this topic is beyond the scope of this eTool; however, a general discussion of common
hazards and related control measures are provided.
