Introduction Fibreglass reinforcement industry employees are exposed to both fibreglass and the agents used in the reinforcing process. Adverse respiratory outcomes have been associated with fibreglass resins and agents in the reinforced plastic workplace.

Objectives The aim of this study was to determine the exposure-related adverse respiratory outcomes among employees in the reinforced plastic workplace.

Methods A cross-sectional study was conducted in the fibreglass reinforcement industry based in KwaZulu-Natal, South Africa. Personal monitoring of styrene and spirometry were conducted. Total cumulative exposure was calculated for each participant’s lifetime of employment in the company. The 254 employees were interviewed by completing a detailed questionnaire based on respiratory health and occupational exposures. Lung function tests were conducted for all employees according to South African Thoracic Society (SATS) standards.

Results The geometric mean of styrene exposure level for the General Laminating Department was 48.2 mg/m3 (95% CI 36.3–64.1 mg/m3) and the Fitting Department was 20.7 mg/m3 (95% CI: 15.6–27.5 mg/m3. The total styrene cumulative exposure odds ratios for chronic cough, phlegm, wheezing and breathlessness in the high exposure category was 3.1 (95% CI 1.1- 8.6), 5.3 (95% CI 1.7- 16.6), 3.3 (95% CI 1.2- 9.1) and 5.5 (95% CI 1.15–26.4), respectively. The cumulative exposure associated reduction, adjusted for smoking and doctor-diagnosed TB, in FEV1/FVC ratio, percent predicted FEV1 and FVC was 0.01, 0.04% and 0.05%, respectively.

Conclusion Styrene exposure increases the risk of respiratory symptoms and is associated with reduced lung function.