[Dueller]

What does the research show about the health and safety of rock and slag wool?
The health aspects and safe use of mineral wools have been examined for nearly 70 years. NAIMA and its member companies have invested tens of millions of dollars in research projects - with leading independent laboratories and universities in the United States and abroad - to investigate the possible human health effects of rock and slag wool as well as other synthetic vitreous fibers (SVFs), such as fiber glass.

Industry studies, as well as studies by governments and others, have examined the following:


Airborne levels of rock and slag wool fibers during their manufacture, installation and use;


The health of more than 13,000 current and former workers engaged in the manufacture of rock and slag wool in the United States and Europe; and


The effects of rock and slag wool on laboratory animals.


Findings from all types of studies have been consistent. Airborne levels of respirable rock and slag wool fibers have been demonstrated to be very low, less than one fiber per cubic centimeter of air (1 f/cc) in most instances. Studies among workers have demonstrated no consistent association between lung cancer or non-malignant respiratory disease and occupational exposure to rock and slag wool.

For more details on recent scientific studies on the health aspects of rock and slag wool insulation, visit the Research section of this site or visit the NAIMA Literature Library for a complete listing of health and safety literature.

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Do rock or slag wools cause cancer in people?
Studies examining possible health effects and safe use of mineral wools have found no consistent association between exposure to rock and slag wool and respiratory disease or cancer in humans. The weight of the scientific evidence confirms that rock and slag wool are safe to manufacture, install and use when manufacturers' recommended work practices are followed.

In October 2001, an international expert review by the International Agency for Research on Cancer (IARC) re-evaluated the 1988 IARC assessment of glass fibers and removed glass, rock and slag wool fibers from its list of substances "possibly carcinogenic to humans." All fiber glass and rock and slag wools that are commonly used for thermal and acoustical insulation are now considered not classifiable as to carcinogenicity to humans (Group 3). IARC noted specifically: "Epidemilogic studies published during the 15 years since the previous IARC Monographs review of these fibers in 1988 provide no evidence of increased risks of lung cancer or mesothelioma (cancer of the lining of the body cavities) from occupational exposures during manufacture of these materials, and inadequate evidence overall of any cancer risk." The IARC downgrade is consistent with the conclusion reached by the U.S. National Academy of Sciences, which in 2000 found “no significant association between fiber exposure and lung cancer or nonmalignant respiratory disease in the MVF [man-made vitreous fiber] manufacturing environment.”


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Do rock and slag wool fibers contribute to problems with indoor air quality?
Rock and Slag wool fibers actually improve the indoor environment by controlling heat loss or gain while reducing condensation and also providing acoustical insulation. Once rock or slag wool products are installed, no significant fiber release occurs.

The majority of airborne fiber levels in buildings containing one or more rock and/or slag wool products are very low, generally less than 0.001 f/cc. In fact, in 1990 the World Health Organization's Working Group on Indoor Air Quality reviewed all scientific studies and concluded: "Current airborne man-made mineral fiber concentrations in indoor environments are considered to represent an insignificant risk."