Man-made vitreous (silicate) fibres with random orientation with alkaline oxide and alkali earth oxide (Na2O+K2O+CaO+MgO+BaO) content greater than 18 % by weight

Endpoint summary

Description of key information

FMMVF fibres are assessed to have no acute toxicity by ingestion, by skin contact or by inhalation. FMMVF shall not be classified as an acute toxicant according to the criteria in Council Directive 67/548/EEC and Regulation (EC) 1272/2008. 

Additional information

Testing of acute oral and dermal toxicities is waived based on the fact that FMMVF fibres are inorganic fibres, whose physicochemical properties suggest a low potential for crossing biological membranes and consequently a low potential for absorption through the gastrointestinal tract and through the skin.Study of acute inhalation toxicity is waived because results from long-term inhalation toxicity studies are available. No man-made mineral fibre in general has shown an acute toxic effects even after very large inhalation and instillation studies where physical damage was avoided.

No treatment related lethality or acute effects are seen even after instillation or inhalation studies using very large doses, where physical damage due to the morphology of the fibres is avoided. As part of reproductive toxicity testing in a number of other MMVF of similar composition and morphology, male and female rats were treated with these substances under consideration by gavage at 250mg/kg/day and elicited no signs of toxicity. Although this is not strictly an acute toxicity test this supports our waiving argument.

Testing the acute toxicity of a material such as this is extremely difficult. In accordance with annex xi section 1 acute oral toxicity testing is not scientifically necessary. Administering sufficiently large doses to produce an acute effect would physically damage the nose, throat and mouth of any animal.

Other studies of similar MMVF have been consulted ; one study where rats were fed up to 2.5% of the MMVF in diet over two years without evident toxicity. A chronic inhalation study used a fibre test atmosphere of 28 mg/m3 without evident toxicity. Taken together with the chemically inert nature of the substance and the absence of absorption/ systemic distribution this information makes low acute inhalation toxicity of the fibres predictable and new animal testing unjustifiable. A lack of absorption and systemic distribution following repeated oral intake. Taken together with the chemically inert nature of the substance makes acute dermal toxicity predictably insignificant and new animal testing unjustifiable.

Justification for classification or non-classification

FMMVF fibres are inorganic fibres, whose physicochemical properties suggest a low potential to cross biological membranes. Thus FMMVF fibres have a low potential for absorption into the body through the skin, the airways and the gastrointestinal tract. FMMVF fibres are assessed to have no acute toxicity by skin contact or if ingested. Long-term inhalation studies showed that FMMVF fibres caused minimal collagen deposition in the lungs and induced fibrosis, but no significant neoplastic changes in the lungs or in pleura. Furthermore, the mortality rate in the exposed animals was the same as for the control animals. Based on these studies FMMVF fibres are assessed to have no acute toxicity by inhalation. FMMVF fibres shall not be classified as an acute toxicant according to the criteria in Regulation (EC) 1272/2008.