Dr. David Weissman, Director of the Respiratory Disease Studies Division for the
National Institute for Occupational Safety and Health (NIOSH), and Max Kiefer, Director
of the NIOSH Western States Office, have recommended protection for workers who
may be exposed to erionite, a naturally occurring mineral found in volcanic ash altered by
weathering and ground water.
In its fibrous form, erionite can be problematic when it is disturbed and becomes
airborne. Erionite fibers pose an inhalation hazard, which research has shown to be 100
to 800 times more lethal than asbestos.
Residents of Cappadocian villages in Turkey use erionite-containing rock to construct
homes. The inhabitants have been found to have a very high risk of developing
malignant mesothelioma. Erionite is also quite prevalent in the sedimentary rocks of the
Western United States.
Until recently, erionite was not considered a hazard in North America, because little
risk for exposure was foreseen; however, evidence linking exposure to erionite with
serious adverse health effects suggests that some workers have a greater potential for
exposure than previously recognized.
The first North American case of erionite-related lung disease was observed in 1981.
The victim was a Utah construction worker who lived in an area rich in zeolite deposits.
He had extensive parenchymal and pleural fibrosis, and a lung biopsy revealed the
presence of fibrous and nonfibrous particles that had compositions consistent with
erionite.
Erionite-related disease has most often been reported in road construction and
maintenance workers who have occupational exposures to erionite-containing gravel
used in road surfacing.
Erionite has been designated a known human carcinogen and the US Geological
Survey found that erionite fibers from Turkey, North Dakota, and Oregon were
chemically and morphologically similar.
Precautions to protect workers by limiting the generation and inhalation of
erionite-contaminated dust should be in place, yet there are neither regulatory or
consensus standards, nor occupational exposure limits for airborne erionite fibers. The 14
steps recommended by NIOSH below are nonobligatory, but represent a sensible
preliminary step in addressing the hazards of erionite exposure.
A good approach to protecting workers would be to utilize the precautions
described in OSHA's guidance for working with asbestos (29 CFR 1910.1001). Weissman
and Kiefer have also made the following risk-reduction recommendations in an attempt
to limit exposure to gravel or soil that may contain erionite:
- Train workers about the hazards of erionite and control methods for reducing
exposure.
- Know where erionite containing material may be encountered prior to beginning
work.
- Avoid the use of erionite containing aggregate whenever possible.
- Use wet methods to reduce dust generation for road and other work where
erionite is present; use machinery with dust collection systems.
- Limit the number of workers who will be engaged in work with erionite.
- Establish decontamination protocols including changes of clothing, showering before
leaving the worksite, and appropriate cleaning and disposal of personal protective
equipment.
- Ensure that work clothing is not washed at home to prevent erionite fibers from
being brought home on clothes and footwear.
- Prohibit dry sweeping, the use of leaf blowers or compressed air for cleaning.
- Protect employees with personal protective equipment, including respiratory
protection.
- Prohibit eating, drinking, or smoking in dusty work areas where erionite fibers may
be airborne. Workers should move away from the work area for breaks and wash their
hands and face before eating, drinking, or smoking.
- Establish protocols for vehicle use on erionite-containing roads (drive slowly, vents
closed, windows up).
- Wet-wash equipment and vehicle exteriors, and wet-clean using High Efficiency
Particulate Air (HEPA) filter vacuuming of vehicle interiors.
- Follow the EPA procedures for proper disposal of waste and debris containing
erionite.
- Prevent visitors and workers from standing in work areas where erionite fibers may
become airborne.
