Occupational exposure to alkoxysilanes in a fibreglass manufacturing plant.

Objective: To assess the exposure of workers to alkoxysilanes and to determine the main route of exposure during the manufacture of fibreglass.

Methods: Occupational hygiene samples were taken from workers and their environment in a fibreglass factory during filament forming and the handling of coated fibres. The total exposure of workers to silanes was assessed by the collection of air samples into impinger flasks at stationary sampling sites, by the use of absorbent patch samples on workers' clothes or skin and from handwash samples. During the time of our field survey, 3-aminopropyltriethoxysilane, 3-glycidoxypropyltrimethoxysilane and 3-methacryloxypropyltrimethoxysilane were being used in different sizing mixtures. The samples were analysed by gas and liquid chromatography.

Results: The silane concentrations in the air samples were below the detection limits of the analytical methods. The mean dermal exposure to 3-glycidoxypropyltrimethoxysilane, analysed from the patch samples, was 2,800 mg h(-1) in the forming room and 800 mg h(-1) in the winder room. The corresponding figures for 3-methacryloxypropyl-trimethoxysilane were 3 and 9 mg h(-1). As determined in the handwash samples, the mean exposure to 3-glycidoxypropyltrimethoxysilane through the hands was 1,500 mg h(-1) in the forming room and 1,800 mg h(-1) in the winder room, the respective values for 3-methacryloxypropyltrimethoxysilane being 110 mg h(-1) and 90 mg h(-1). Only small quantities of 3-aminopropyltriethoxysilane were found in a few handwash samples.

Conclusions: Our results showed that the workers in the fibreglass factory were clearly exposed to silanes. The main route of potential exposure was through the skin, especially the hands, which emphasised the importance of wearing appropriate protective gloves. According to the patch sampling, on average two thirds of the total dermal exposure was caused by exposure of the forearm, as indicated by the amounts of silanes analysed in the forearm patches. Since almost every worker was wearing protective gloves, the main occupational health finding concerning exposure to silanes was that short-sleeved T-shirts did not provide any protection to the arms.