Health Effects and Medical Surveillance
This domain tests dose, latency, fiber type, and the exact triggers for a medical surveillance program, not general awareness that asbestos is harmful.
The disease set
Asbestosis is dose-related fibrosis with roughly 10 to 20 years latency. Lung cancer risk multiplies with cigarette smoking rather than simply adding. Mesothelioma, pleural or peritoneal, appears after 20 to 50 years and at comparatively low doses, with amphiboles such as amosite and crocidolite carrying the strongest association. Laryngeal and ovarian cancer are also recognized. Pleural plaques and diffuse thickening mark exposure but are not the compensable diseases themselves.
Limits and counting
OSHA sets a PEL of 0.1 f/cc as an 8-hour TWA and a 30-minute STEL of 1.0 f/cc. Phase contrast microscopy counts only fibers longer than 5 micrometers with a length-to-width ratio of at least 3:1, which is why the fiber type on the bulk report matters: chrysotile clears from the lung faster than amphibole.
Surveillance triggers, 1926.1101(m)
Required when an employee is exposed at or above the PEL for 30 or more days per year, or performs Class I, II, or III work for 30 or more days per year. Exam within 30 days of assignment, then annually: work and medical history, chest X-ray read by a B-reader, spirometry, and any additional test the physician orders. The physician sends a written opinion to the employer; the employee receives a copy and, on request, the underlying results. Keep records 30 years. Respirator use separately triggers a 1910.134 medical evaluation.
Worked example
A worker pulls vinyl tile, Class II work, 60 days a year. Sixty is at or above 30, so annual surveillance applies. A second worker does Class III glove bag repairs five days a year, which does not itself trigger surveillance unless monitoring shows PEL-level exposure on 30 or more days.
Traps
Confusing exposure monitoring with medical surveillance; assuming a clean X-ray ends the program; treating smoking as a substitute explanation rather than a multiplicative co-factor.