The National Institute for Occupational Safety and Health
(NIOSH)
periodically issues documents to transmit new information or to
update
existing information on specific chemical substances, physical
agents,
or safety hazards found in the workplace. One such recently issued
document is summarized below. It is available for distribution as
indicated.
On July 5, 1985, NIOSH released Current Intelligence Bulletin
#44*: Dinitrotoluenes. Dinitrotoluene (DNT) is used in the
manufacture of dyes, munitions, and explosives, but its major use
today (99%) is in the synthesis of toluenediamine (TDA), an organic
intermediate in the production of polyurethane. In 1982,
approximately 720 million pounds of technical grade DNT (TDNT) were
produced in the United States. NIOSH estimates that as many as
1,300
workers are exposed to various forms of DNT.
NIOSH recommends that TDNT and the 2,6 isomer of DNT (2,6-DNT)
be
considered potential human carcinogens in the workplace. Exposure
to
TDNT or 2,6-DNT has been shown to produce malignant tumors in rats
and
mice. In addition, a reproductive hazard may exist for workers
exposed to TDNT or 2,6-DNT. This concern is based on testicular
atrophy, decreased spermatogenesis, or aspermatogenesis seen in
three
species of experimental animals exposed to TDNT or 2,6-DNT and on
nonfunctioning ovaries in mice exposed to TDNT. Although evidence
is
limited indicating that 2,4-dinitrotoluene (2,4-DNT) poses a risk
to
human health, the existing animal and in vitro data are suggestive
of
such a potential. As prudent public health policy, NIOSH
recommends
that employers assess the conditions under which workers may be
exposed to TDNT or the isomers of DNT and take all reasonable
precautions to reduce exposure to the fullest feasible extent.
The strains of animals used, the doses and routes selected for
administration of the test compounds, and the short duration of
several studies impose limitations on the interpretation of these
studies. However, NIOSH has determined that the collective
toxicologic data on metabolism, mutagenicity, carcinogenicity, and
reproductive effects provide sufficient evidence to warrant concern
for adverse health effects from occupational exposure to TDNT or
2,6-DNT.
Workers may be exposed to DNT by the dermal and inhalation
routes;
concentrations have ranged from not detectable to 0.89 mg/m((3)).
Guidelines for minimizing worker exposure to DNT include
recommended
procedures and equipment for controlling worker exposure (e.g.,
contamination control, worker isolation, or personal protective
equipment) and recommendations for exposure monitoring and medical
surveillance.
Copies are available without charge from Publications
Dissemination Section, Division of Standards Development and
Technology Transfer, National Institute for Occupational Safety and
Health, 4676 Columbia Parkway, Cincinnati, Ohio 45226; (513)
841-4287.
Reported by Div of Standards Development and Technology Transfer,
National Institute for Occupational Safety and Health, CDC.
*NIOSH issues current intelligence bulletins (CIBs) to disseminate
new
scientific information about occupational hazards. A CIB may draw
attention to a hazard previously unrecognized or may report new
data
suggesting that a known hazard is either more or less dangerous
than
was previously thought.
Disclaimer
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