The occupational scene of styrene

Area of Science:

• Industrial Hygiene
• Polymer Chemistry
• Occupational Health

Background:

• Styrene is a key monomer in polymer production and a reactive solvent in unsaturated polyester resins.
• While closed polymerization processes often maintain low styrene exposure, peaks can occur during maintenance and transport.
• Open mould processes, like manual lamination, present significantly higher and more variable styrene exposure risks.

Purpose of the Study:

• To evaluate worker exposure levels to styrene in various industrial processes.
• To identify specific tasks and scenarios associated with high styrene exposure.
• To assess the effectiveness of current control measures and propose improved strategies.

Main Methods:

• Monitoring of airborne styrene concentrations during different industrial operations.
• Comparison of measured exposure levels against established hygienic standards (8-h TWA and short-term reference values).
• Evaluation of exposure risks related to styrene oxide, a suspected carcinogen.

Main Results:

• Open mould lamination processes result in average styrene exposures 2-3 times the 8-h TWA standard (20 ppm).
• Short-term exposures during open mould processes frequently exceed twice the short-term reference value (100 ppm).
• Exposure to styrene oxide is an additional risk in these processes.

Conclusions:

• Current practices in open mould lamination lead to unacceptable styrene exposure levels for workers.
• Improved ventilation, workplace design, and safe work habits can reduce exposure.
• Automation and the adoption of closed moulds are the most effective long-term solutions for minimizing styrene exposure in the reinforced plastic industry.