Dust and gas exposure in tunnel construction work

Area of Science:

• Occupational Health and Safety
• Environmental Science
• Industrial Hygiene

Background:

• Underground construction involves diverse tasks with varying potential exposures to dust and gases.
• Assessing these exposures is crucial for protecting worker health and ensuring compliance with occupational exposure limits (OELs).

Purpose of the Study:

• To quantify personal exposures to dust and gases among different occupational groups in underground construction.
• To compare these exposures against established Norwegian occupational exposure limits (OELs).

Main Methods:

• Personal air sampling for total dust, respirable dust, respirable alpha-quartz, oil mists, and nitrogen dioxide.
• Inclusion of 189 workers across seven occupational groups and an outdoor reference group.
• Geometric mean (GM) calculations to represent central exposure tendencies.

Main Results:

• Shotcreters, shaft drillers, and tunnel-boring machine workers exhibited the highest geometric mean (GM) exposures to total dust (6-7 mg/m3) and respirable dust (2-3 mg/m3).
• Shaft drillers and tunnel-boring machine workers exceeded the Norwegian OEL for respirable alpha-quartz (0.1 mg/m3) with GM exposures of 0.3-0.4 mg/m3.
• Shaft drillers had the highest GM exposure to oil mists (1.4 mg/m3), primarily from pneumatic drilling.

Conclusions:

• Specific underground construction roles, such as shotcreting and drilling, are associated with significantly elevated dust and crystalline silica exposures.
• Exceedances of the OEL for respirable alpha-quartz highlight a critical risk for shaft drillers and tunnel-boring machine operators.
• Further controls are necessary to mitigate exposures to dust, crystalline silica, and oil mists in these high-risk occupations.