US EPA

3089689 

Journal Article 

Review 

Man‐made vitreous fibres: Evaluation of risks to health from environmental exposure in Canada 

Meek, ME; Long, G 

1994 

Yes 

Journal of Environmental Science and Health, Part C: Environmental Carcinogenesis & Ecotoxicology Reviews
ISSN: 1059-0501
EISSN: 1532-4095 

12 

2 

361-387 

English 

10.1080/10590509409373453 

WOS:A1994PT42700021 

“Mineral fibres” are included on the List of Priority Substances to be assessed under the Canadian Environmental Protection Act. This assessment addresses several categories of man‐made vitreous fibres for which the databases were considered to be sufficient to permit assessment.

On the basis of the excess in respiratory and lung cancer observed among production workers in epidemiological studies conducted to date, rock/slag wool is considered “possibly carcinogenic to humans”. Adverse effects of exposure to rock wool (only) have been observed in toxicological studies in animal species only at concentrations much greater (by more than 350 times) than the highest concentrations measured in the indoor environment in living areas during the installation of blown rock wool insulation.

On the basis of the lack of observed excesses of cancer in glass wool production workers in the most extensive epidemiological studies conducted to date, and the lack of observation of significant increases in tumour incidence in animals exposed by inhalation and inconclusive evidence concerning their potential to induce tumours following intrapleural or intraperitoneal administration, glass wool (excluding glass microfibre) is considered “unlikely to be carcinogenic to humans”. Classification as “possibly carcinogenic to humans” might also be appropriate, since small increases in cancer incidence or mortality would not have been detected in the available epidemiological studies, and because of variations in fibre size distributions to which humans and rats are exposed. Only minimal effects (not adverse) of exposure to glass wool (excluding glass microfibre) have been observed in toxicological studies in animal species at concentrations much greater (by more than 75 times) than the highest concentrations measured in the indoor environment in living areas during the installation of glass wool insulation.

Adverse effects of exposure to glass microfibre have not been observed in limited epidemiological studies of populations in the occupational environment or in animals exposed to considerably higher concentrations than those likely to be present in the generalenvironment. Owing principally to the limitations of these studies and based upon positive results in studies involving intracavitary administration and supporting in vitro results, glass microfibre is considered “possibly carcinogenic to humans”. Since glass microfibre is not known to be produced in Canada and is used principally in specialty applications, concentrations in the general environment are expected to be very low.

Adverse effects of continuous glass filament have not been observed in epidemiological studies of populations exposed occupationally to considerably higher concentrations than those likely to be present in the general environment (though quantitative data on the latter are lacking). Due to the limited power of some of the epidemiological studies to detect increases in cancer mortality in continuous filament production workers, and the lack of adequate data on carcinogenicity in animal species, continuous glass filament is considered “unclassifiable with respect to carcinogenicity in humans”. Few respirable fibres are generated in the production and use of continuous filament and therefore it is likely that concentrations in the general environment would be extremely small.

Upon the basis principally of the increased incidence of pulmonary tumours in rats and increases in mesotheliomas in rats and hamsters observed in inhalation bioassays and those involving intratracheal and intracavitary administration and supporting results in vitro. refractory ceramic fibre has been classified as “probably carcinogenic to humans”. Owing to its use principally in high temperature industrial applications, with the exception possibly of areas in the vicinity of industrial sources for which relevant Canadian data were not identified, priority for consideration of options to reduce exposure of the general population to refractory ceramic fibre compared to that of other substances in the Priority Substances Program is considered to be very low.