We analyzed results from the medical examinations of 340 hazardous materials firefighters and applied various objective standards in simulated fitness for duty determinations. Ten percent had elevated blood pressures, 13% had far visual acuity worse than 20/30 in one or both eyes, and 38% had abnormal audiometry. The strictest standards for resting blood pressure and corrected visual acuity would have failed 2% and 1% of the cohort, respectively. For audiometry, 0%-5% of the cohort would have failed, depending on the hearing requirements set. The strictest hearing standard did not allow for corrective devices so that few failures would be reversible. Visual and audiometric testing and measurement of resting blood pressure all have significant clinical yields. Studies of simulated firefighting are needed to establish minimum hearing requirements and determine whether corrective devices can be worn safely during duty.