Occupational exposure to alkoxysilanes in a fibreglass manufacturing plant

Objective: To assess the exposure of workers to alkoxysilanes and to determ ine the main route of exposure during the manufacture of fibreglass. Method s: Occupational hygiene samples were taken from workers and their environme nt in a fibreglass factory during filament forming and the handling of coat ed fibres. The total exposure of workers to silanes was assessed by the col lection of air samples into impinger flasks at stationary sampling sites, b y the use of absorbent patch samples on workers' clothes or skin and from h andwash samples. During the time of our field survey, 3-aminopropyltriethox ysilane, 3-glycidoxypropyltrimethoxysilane and 3-methacryloxypropyltrimetho xysilane were being used in different sizing mixtures. The samples were ana lysed by gas and liquid chromatography. Results: The silane concentrations in the air samples were below the detection limits of the analytical method s. 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 sampl es, the mean exposure to 3-glycidoxypropyltrimethoxysilane through the hand s was 1,500 mg h(-1) in the forming room and 1,800 mg h(-1) in the winder r oom, the respective values for 3-methacryloxypropyltrimethoxysilane being 1 10 mg h(-1) and 90 mg h(-1). Only small quantities of 3-aminopropyltriethox ysilane were found in a few handwash samples. Conclusions: Our results show ed that the workers in the fibreglass factory were clearly exposed to silan es. The main route of potential exposure was through the skin, especially t he hands, which emphasised the importance of wearing appropriate protective gloves. According to the patch sampling, on average two thirds of the tota l dermal exposure was caused by exposure of the forearm, as indicated by th e amounts of silanes analysed in the forearm patches. Since almost every wo rker was wearing protective gloves, the main occupational health finding co ncerning exposure to silanes was that short-sleeved T-shirts did not provid e any protection to the arms.