Asbestos is a fibrous mineral mined and used for decades in products ranging from insulation to cement, floor and ceiling tiles, adhesives, and friction products. It has been more than forty years since scientists confirmed the link between asbestos and malignant pleural mesothelioma, an aggressive cancer of the lining around the lungs and its use is now heavily regulated in the U.S. In recent years, another mineral called erionite, has also been implicated in mesothelioma cases.
Now, a study conducted in France suggests that two other types of mineral particles used in industry may increase the risk of mesothelioma, particularly in people who are also exposed to asbestos. Researchers in Bordeaux, France compared the cases of 1,199 male industrial workers with mesothelioma with 2,370 healthy industrial workers, paying close attention to each worker’s level of exposure to asbestos, mineral wool and silica.
Mineral wool is a fibrous material made by combining slag, granite and other materials at high temperature. Like asbestos, mineral wool has high tensile strength and is resistant to fire, rot and moisture. It is used in many of the same industrial applications as asbestos. Silica is a crystalline compound abundant in the earth’s crust and used in the manufacture of glass and ceramics and as an additive to abrasives. It occurs in several forms, the most common of which is quartz.
According to the French study published in the American Journal of Respiratory and Critical Care Medicine, complete job histories were collected for each study subject and their exposure to asbestos, mineral wool, and silica were assessed using three different French job exposure matrices. Adjustments were made for each person’s age, birth date and occupational asbestos exposure.
The news was not good for industrial workers. Researchers found “a significant association between mesothelioma and mineral wool exposure”, even after adjusting for occupational asbestos exposure. As with asbestos, the greater the exposure to mineral wool, the higher the risk for mesothelioma. Just as disturbing, for study subjects exposed to both asbestos and mineral wool and, to a lesser degree, for study subjects exposed to both asbestos and silica, the risk of mesothelioma was higher than for those exposed to asbestos alone.
“Our results are in favor of an increased risk of pleural mesothelioma for subjects exposed to both asbestos and mineral wool or asbestos and silica,” concludes the report. Asbestos is believed to trigger mesothelioma by causing chronic irritation and inflammation. Inhalation of other irritating particles may compound the effect.