Carbon Nanotubes: Probabilistic Approach for Occupational Risk Assessment

Area of Science:

• Occupational health and safety
• Nanomaterial risk assessment
• Environmental science

Background:

• Carbon nanotubes (CNTs) are increasingly used in various industries.
• Assessing occupational exposure risks is crucial for worker safety.
• Previous studies provide data on chronic and subchronic inhalation of CNTs.

Purpose of the Study:

• To conduct an occupational risk assessment for carbon nanotubes (CNTs) via a probabilistic approach.
• To evaluate risks associated with different work events in CNT production.
• To determine the probability of relevant occupational risk occurrence.

Main Methods:

• Hazard identification using chronic and subchronic inhalation exposure studies.
• Derivation of a guidance value (BMC h) for occupational inhalation exposure to CNTs.
• Probabilistic risk assessment using exposure scenarios and risk characterization ratios (RCRs).

Main Results:

• A guidance value (BMC h) was established as a lognormal distribution (10.0 ± 4.2 µg/m³).
• Three work events (WEs) related to conductive film production were analyzed.
• All WEs showed RCR distributions ≥ 1, indicating risk; WE2 (no LEV) was statistically significant.

Conclusions:

• The probabilistic approach effectively characterizes occupational risks associated with CNTs.
• Manufacturing CNT films without local exhaust ventilation poses a significant occupational risk.
• Risk management strategies, such as implementing LEV, are essential in CNT handling environments.