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Publication of NIOSH Criteria Documents on Welding, and
Brazing,Thermal Cutting and on Radon Progeny
The National Institute for Occupational Safety and Health (NIOSH)
periodically issues criteria documents that examine health risks
associated with various occupations. Two such documents were
recently
published* and are described below.
Criteria for a Recommended Standard: Welding, Brazing, and Thermal
Cutting. This document examines the occupational health risks
associated with welding, brazing, and thermal cutting and provides
criteria for eliminating or minimizing the risks encountered by
workers
in these occupations. An estimated 700,000 workers in the United
States
are involved in the welding of various materials. The major health
concerns associated with these occupations are increased risks of
lung
cancer and acute or chronic respiratory diseases.
The etiologic basis for this excess risk is difficult to determine
because of uncertainties about smoking habits, possible
interactions
among the various components of welding emissions, and possible
exposures to other occupational carcinogens. For workers who weld
on
stainless steel, the increased risk for lung cancer appears to be
associated with exposure to fumes that contain nickel and chromium.
The prevalence and severity of nonmalignant respiratory conditions
are
not well characterized among welders, but these conditions have
been
observed in both smoking and nonsmoking workers in
welding-associated
occupations. Excess morbidity and mortality exist among welders
even
when reported exposures are below current Occupational Safety and
Health Administration (OSHA) permissible exposure limits (PELs) for
the
many individual components of welding emissions.
An occupational exposure limit for total welding emissions cannot
be
established because the composition of welding fumes and gases
varies
for different welding processes and because the various components
of a
welding emission may interact to produce adverse health effects.
Therefore, exposures to all welding emissions should be reduced to
the
lowest feasible concentrations using state-of-the-art engineering
controls and work practices. Any applicable exposure limits for
individual chemical and physical agents associated with welding
(i.e.,
NIOSH recommended exposure limits (RELs), OSHA PELs, or limits
recommended by consensus groups) should be considered as upper
boundaries of exposure.
The criteria document contains NIOSH recommendations for medical
monitoring of exposed workers and for engineering controls, good
work
practices, and worker education. Guidelines are also provided for
respiratory protection and protective clothing.
A Recommended Standard for Occupational Exposure to Radon Progeny
in
Underground Mines. This document examines the occupational health
risks
associated with exposures to radon progeny (radon and its
short-lived,
alpha-radiation- emitting, radioactive decay products) in
underground
mines, and it establishes criteria for minimizing the risks
encountered
by miners.
Data from studies on both humans and animals demonstrate a direct
link
between exposure to radon progeny and lung cancer. Epidemiologic
studies provide a basis for quantitatively estimating human risk at
various exposure levels. Exposure is quantified using the working
level
month (WLM), which is a standard measure of occupational exposure
to
alpha radiation. Analyses show that an exposure to radon of 4 WLM
per
year over a 30-year working lifetime (the current Mine Safety and
Health Administration standard) poses a substantial risk of lung
cancer. To determine a REL, NIOSH has weighed this evidence along
with
uncertainties in the data and the feasibility of controlling
exposure
to radon progeny in mines. The resulting REL for radon progeny is a
cumulative total of 1 WLM per year and an average workshift
concentration of one twelfth of 1 working level. These limits are
to be
considered the upper boundaries of exposure, and every effort
should be
made to reduce exposures to the lowest concentrations possible. In
addition to the REL, the criteria document contains specific
provisions
for medical monitoring, recordkeeping, respiratory protection,
worker
education, and sampling and analytical methods. Implementation of
all
these recommendations will help minimize risk for exposed workers.
Reported by: Div of Standards Development and Technology Transfer,
National Institute for Occupational Safety and Health, CDC.
*Copies of the documents can be obtained without charge from the
Information Dissemination Section, Division of Standards
Development
and Technology Transfer, National Institute for Occupational Safety
and
Health, 4676 Columbia Parkway, Cincinnati, Ohio 45226; telephone:
(513)
533-8287.
Disclaimer
All MMWR HTML documents published before January 1993 are electronic conversions from ASCII text into HTML. This conversion may have resulted in character translation or format errors in the HTML version. Users should not rely on this HTML document, but are referred to the original MMWR paper copy for the official text, figures, and tables. An original paper copy of this issue can be obtained from the Superintendent of Documents, U.S. Government Printing Office (GPO), Washington, DC 20402-9371; telephone: (202) 512-1800. Contact GPO for current prices. **Questions or messages regarding errors in formatting should be addressed to mmwrq@cdc.gov. Page converted: 08/05/98
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