Chinese drywall may be getting all the press coverage of late, but an older and more familiar foe continues to plague America's buildings. A January report from the Department of Health and Human Services Centers for Disease Control and Prevention National Institute for Occupational Safety and Health (NIOSH) predicts that health damage from asbestos will continue for decades, some 30 years after warnings were first issued.
Recognizing the health dangers of the substance, in the 1970s federal enforcement agencies developed regulatory definitions and standards for exposure to airborne asbestos fibers. These actions resulted in a significant reduction in the use of asbestos, and a total end to asbestos mining in 2002. However, many asbestos products remain in use and new asbestos-containing products continue to be manufactured in or imported into the U.S.
According to OSHA estimates, some 1.3 million workers in general industry continue to be exposed to asbestos; NIOSH estimates that nearly 45,000 mine workers may be exposed.
Deaths Increase
NIOSH has annually tracked U.S. asbestosis deaths since 1968 and malignant mesothelioma deaths (shown to have a significant link to asbestos) since 1999. The agency has used death certificate data in the National Occupational Respiratory Mortality System (NORMS) for this portion of its research. The NORMS data, representing all deaths among U.S. residents, show that asbestosis deaths increased almost 20-fold from the late 1960s to the late 1990s.
The seeming discrepancy between lower asbestos mining and higher death rates was addressed in the NIOSH report: "Mortality trends are expected to substantially trail trends in asbestos exposures for two primary reasons: 1) the latency period between asbestos exposure and asbestosis onset is typically long, commonly one or two decades or more; and 2) asbestosis is a chronic disease, so affected individuals can live for many years with the disease before succumbing. Ultimately, it is anticipated that the annual number of asbestosis deaths in the U.S. will decrease substantially as a result of documented reductions in exposure. However, asbestos usage has not been completely eliminated, and asbestos-containing materials remain in place in structural materials and machinery, so the potential for exposure remains. Thus, asbestosis deaths in the United States are anticipated to continue to occur for several decades."
Short-Term Exposure
The NIOSH study made note of how the nature of occupational exposures to asbestos has changed over the last several decades. According to the report: "Once dominated by chronic exposures in asbestos textile mills, friction product manufacturing, cement pipe fabrication, and insulation manufacture and installation, current occupational exposures to asbestos in the U.S. primarily occur during maintenance activities or remediation of buildings containing asbestos. These current occupational exposure scenarios frequently involve short-term, intermittent exposures, and proportionately fewer long fibers than workers were exposed to in the past."
To date, studies on how dangerous these short-term exposures are have been limited; researchers are still determining whether or not there is an asbestos exposure threshold below which workers would incur no risk of adverse health outcomes.
To broaden its research capability on asbestos, NIOSH has announced plans to partner with a myriad of other federal agencies, along with labor, industry, academia, practitioners, and others, including international groups.
The extensively researched and heavily annotated study is available online at www.cdc.gov/niosh.
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