Glass fibres: absence of pulmonary hazard in production workers.

Glass fibres: absence of pulmonary hazard in production workers. Seventy fibreglass workers with a mean of 19-85 years in the industry are compared with a control group having no exposure to glass fibre but otherwise matched for age, sex, height, and weight, and residing in the same geographical area. Comparison was made by radiography, the administration of the modified Medical Research Council Short Questionnaire on Respiratory Symptoms (1960), amplified to include a detailed occupational history, and measurement of peak expiratory flow, FEV1, and FVC. Statistical analysis showed the control group to be at a slight disadvantage compared to the subject group in respect of complaints of phlegm and FVC. No evidence of any respiratory hazard due to glass fibre is shown. Since their early manufacture in the 1930s, the diameter of glass fibres has reduced from a manufacturing specification of 15 microns (range 6-20) to 7 microns (range 0-5-25), and the method of bonding has changed from oils to bitumen to phenol-formaldehyde resins, both changes making it possible that a larger amount of respirable dust is evolved during manufacture and processing of the material, and introducing an additional possible hazard of resin sensitization while the uncured material is handled. The material's siliceous nature and morphological similarity to asbestos fibres, and the resinous nature of the bonding size have all given rise to speculation as to a possible pulmonary hazard, in spite of the fact that glass contains no free silica and is totally different from asbestos in its chemical composition. Methods The present study was designed to allow comparisons to be made between a group of 70 workers with a lengthy exposure to glass fibre and a control group matched for age, sex, height, and weight. The two groups worked in the same town, the controls being drawn from the same geographical area to minimize independent environmental factors. The control group was employed in glass warehouses where there is no significant exposure to dust and where fibreglass was not used. The subject group had periods of 12 to 24 years' exposure to glass fibre dust in the manufacturing industry with a mean exposure of 19-85 years. Workers who had been exposed to dust or fumes in previous occupations were excluded from the survey and matching was achieved to 5 or less years of age, 1 inch (25-4 mm) of height, and 7 lb. (3-2 kg) of weight. Chest radiographs were …