OSHA revises standards on hexavalent chromium
The Occupational Safety and Health Administration (OSHA) released at the end of October 2006 a revised standard that governs regulation of employee exposure to hexavalent chromium.
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The guidelines, issued at
OSHA's 29 CFR Part 1910,
Occupational Exposure to
Hexavalent Chromium, say that
employers must "use feasible
engineering and work practice
controls to reduce and maintain
employee exposures to Cr(VI) at
or below the permissible exposure
limit (PEL) of 5 micrograms per
cubic meter of air (5 m g/m3), calculated as an 8-hour timeweighted average (TWA)."
The revised standard was written for general industry as part of a settlement agreement between OSHA, the Surface Finishing Industry Council (SFIC), Public Citizen Health Research Group (HRG), and the United Steel, Paper and Forestry, Rubber, Manufacturing, Energy, Allied Industrial and Service Workers International Union (Steelworkers).
The complete version of the regulation includes a detailed report of Cr(VI) health effects under the heading "Carcinogenic Effects, (4)Evidence From Stainless Steel Welders." The section states that "fumes and gases associated with the welding process can cause a wide range of respiratory exposures which may lead to an increased risk of lung cancer…The fumes from stainless steel, unlike fumes from mild steel, contain nickel and Cr(VI). There are several cohort and casecontrol studies as well as two meta analyses of welders potentially exposed to Cr(VI). In general, the studies found an excess number of lung cancer deaths among stainless steel welders."
However, at this point in the standard, OSHA expresses doubt on the severity of Cr(VI) exposure amongst welders. The section states that "…few of studies found clear trends with Cr(VI) exposure duration or cumulative Cr(VI). In most studies, the reported excess lung cancer mortality among stainless steel welders was no greater than mild steel welders, even though Cr(VI) exposure is much greater during stainless steel welding. This weak association between lung cancer and indices of exposure limits the evidence provided by these studies. Another limitation was the coexposures to other potential lung carcinogens, such as nickel, asbestos, and cigarette smoke. Nevertheless, these studies add some further support to the much stronger link between Cr(VI) and lung cancer found in soluble chromate production workers, chromate pigment production workers, and chrome platers."
OSHA also examined the fiscal impact of implementing the revised standard in companies that perform stainless steel welding, and found that changes to meet the new standard "could equal 22.3 percent of profits in this industry, but only 0.92 percent of revenues. The maximum price increases required to fully restore profits (0.92 percent) is unlikely to significantly alter the demand for construction welding services… Prices of steel have changed by more than 10 percent within a single year a number of times in the past ten years without affecting the viability of the use of stainless steel in construction." In general industry welding, identified by OSHA as repair and maintenance (NAICS 811) and personal and laundry services (NAICS 812), the agency found that "…even if costs cannot be passed on, the resulting declines in profits are unlikely to affect the viability of an otherwise viable employer. Further, businesses of this kind are more likely to be able to increase costs because of the absence of foreign competition. While some loss of revenue is possible with a price increase, it is unlikely that the quantity of routine repairs would be significantly affected by price increases of this magnitude." In the long run, then, OSHA feels that any price increase made by businesses to cover equipment needed to meet the revised hexavalent chromium standard will not be so significant as to sharply decrease the amount of business from current levels.
In determining a permissible
exposure level for industry,
OSHA originally targeted a lower
level of one microgram per square
meter (1 m g/m3). However, the
agency found such a level
infeasible for welding operations
because welding cannot be
separated into high and low
exposure operations. In the
standard's summary, OSHA says
"welders may perform different
types of welding in the same day,
making it difficult or impossible
for employers to monitor them on
an operation by operation basis."
In addition, because welders doing
different types of welding often
work alongside one another,
OSHA states that "what is
technologically feasible for a
welding operation considered in
isolation may not be
technologically feasible for that
operation when it is performed
next to SMAW on stainless steel,"
a process found by the agency to
produce higher levels of Cr(VI)
than GMAW.
Ultimately, OSHA recommends
the use of engineered systems,
such as fume extraction devices,
as suitable to meet the 5 m g/m3 standard. Such devices, available
in configurations that range from
portable cabinets to central air
handling systems with fume
evacuation ducts running to each
welding station, will be less costly
to shops than individual
respirators for each welder.
Whatever system is selected will
reduce the potential for workers to
develop cancer far better than
opening exterior doors or adding
3-speed floor fans to the work
areas.
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