Experts compare erionite to asbestos, warn about health effects
In a NIOSH Science blog posting, two agency officials describe erionite, outline its historical health data, and identify risk-reduction recommendations.
A naturally occurring mineral usually found in volcanic ash that has been altered by weathering and ground water, erionite fibers only pose a hazard if they are disturbed and become airborne, according to Dr. David Weissman, director of the NIOSH Division of Respiratory Disease Studies, and Max Kiefer, director of the NIOSH Western States Office. The National Toxicology Program has designated erionite a known human carcinogen.
Workers most at risk appear to be those involved in road construction and maintenance. Scientists believe erionite is mostly concentrated in the western U.S.
The first North American with erionite-related lung disease was a road construction worker in Utah whose case was reported in 1981. In 2008, a mesothelioma cluster was described in a small village in central Mexico.
"It has long been known that residents of some Turkish villages where erionite-containing rock was used to construct homes have a remarkably high risk for development of malignant mesothelioma," the researchers said. The U.S. Geological Survey has found that erionite fibers from the Cappadocian region of Turkey, North Dakota, and Oregon were chemically and morphologically similar.
So far there are no regulatory or consensus standards or occupational exposure limits for airborne erionite fibers. The researchers say development of a quantitative OEL awaits the development of a standardized, validated exposure assessment method and quantitative evaluation of risks associated with given exposures.
In the meantime, the researchers offer the following recommendations to reduce the risk of erionite exposures to workers who engage in activities that disturb erionite-containing gravel or soil or crush rocks that contain erionite:
- Use wet methods to reduce dust generation for road and other work, such as in quarries where erionite is present; for example, when drilling rock, apply water through the drill stem to reduce airborne dust or use a drill with a dust collection system.
- Prohibit dry sweeping, use of leaf blowers or compressed air for cleaning.
- Prohibit eating, drinking, or smoking in dusty work areas where erionite fibers may be airborne.
- Wet wash equipment and vehicle exteriors.
- Train workers about the potential hazards of erionite and control methods for reducing potential exposure.
- Know where erionite containing material is present and will be encountered.
- Avoid using erionite containing aggregate when possible.
- Limit the number of workers who will be working with erionite.
- Provide personal protective equipment, including respiratory protection. NIOSH notes this should be done in consultation with an occupational safety and health professional.
- Establish decontamination protocols, such as change of clothing, showering before leaving the work site, and using appropriate cleaning and disposing of personal protective equipment.
- Make sure work clothing is not washed at home to prevent erionite fibers from being brought home on work clothes.
- Follow Environmental Protection Agency procedures for proper disposal of waste and debris that contains erionite.
- Limit bystander exposure by preventing visitors and coworkers from standing in work areas where erionite fibers may become airborne.
Read more at the WorkersComp Forum homepage.
December 15, 2011
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