Health Hazards in Construction
Why health hazards differ
Health effects accumulate over time, so controls focus on exposure limits and monitoring rather than single events. Major construction exposures: respirable crystalline silica, lead, asbestos, noise, welding fumes, solvent vapors, carbon monoxide, hexavalent chromium, cadmium, and heat.
Silica (1926.1153)
The PEL is 50 µg/m³ as an 8-hour TWA; the action level is 25 µg/m³. Table 1 lists common tasks with specified engineering controls and work practices - following the table exactly satisfies the standard without exposure monitoring. Otherwise the employer must assess exposures and apply controls. A written exposure control plan is required once exposures exceed the action level, along with a designated competent person.
Lead and asbestos
Lead in construction (1926.62) has a PEL of 50 µg/m³ and an action level of 30 µg/m³ over 8 hours, with blood lead monitoring triggered at 30 or more days per year above the action level. Asbestos (1926.1101) sets a PEL of 0.1 fibers per cubic centimeter plus a 1 f/cc 30-minute excursion limit.
Noise
The PEL is 90 dBA TWA with a 5 dB exchange rate, so 95 dBA is permitted for only 4 hours.
Trap and rule of thumb
Questions blur "action level" and "PEL." The action level triggers monitoring, training, and often medical surveillance; the PEL is the enforceable limit. For silica, verify the exact Table 1 entry - water alone may not satisfy a task performed in an enclosed space.