The association between exposure to silica (quartz dust), silicosis and lung cancer has been discussed since long in occupational safety and health. However, the interpretation of the results remains still difficult and controversial, because exposure, silicosis status and important confounders and other bias factors like smoking or radon exposure were not systematically taken into account.
The International Agency for Research on Cancer - IARC (1997) classifies crystalline silica inhaled as quartz or cristobalite as a human carcinogen (Group 1), with two restrictions however: this refers to quartz or cristobalite from occupational sources and the association was not detected in all industrial circumstances studied. By contrast, amorphous silica was classified in Group 3, because there are no clear results that allow an evaluation for carcinogenicity, so far.
In 1999, the MAK-Kommission (Maximum-Occupational-Concentration-Commission) of the DFG (Deutsche Forschungsgemeinschaft, German Research Council) classified quartz, cristobalite and tridymite (cristalline silica, alveolar fraction) into category 1 ("chemicals that are carcinogenic to humans and that are expected to contribute to the carcinogenic risk. Epidemiological results give implications enough for an association between human exposure and cancer. Otherwise epidemiological data can be supported by information about the effect mechanism in humans").
In order to support the discussion about consequences on regulation practice, prevention and the adjudication practice in connection with occupational diseases and to formulate open questions, a detailed and actualised review of the results from epidemiology is necessary. The Institute for Occupational Safety - BIA presents the BIA-Report "Quality based critical review (QBCR) of the epidemiological literature on silica, silicosis, tobacco smoking and cancer". In this report the relevant epidemiological studies are analyzed and interpreted.
BIA-Report "Quality based critical review (QBCR) of the epidemiological literature on silica, silicosis, tobacco smoking and cancer"