Respirator Reliance at a Lead-Acid Battery Plant
At a lead-acid battery plant, 30 workers are exposed to lead dust and fume. Personal 8-hour sampling shows 60 µg/m³ at the pasting area, above the 50 µg/m³ permissible exposure limit. The company has issued half-facepiece air-purifying respirators with P100 filters and wants to rely on them while deferring engineering changes. The program has no fit testing, no medical evaluation, no written cartridge change schedule, and one worker with a full beard wears a tight-fitting respirator. Filters are changed only when breathing becomes hard. Training is a 10-minute video at hire. Two workers have blood lead levels of 25 µg/dL, and one reports abdominal cramps. The safety officer must decide whether the respirator program can be approved as proposed.
1. Identify the respirator-program deficiencies and explain why each matters for lead exposure.
Read the worked answer
The program is missing the elements that make a respirator's assigned protection factor credible. Without fit testing, there is no evidence that the half-facepiece seals on each worker; with a full beard, the seal is compromised because facial hair prevents contact with the skin. Without medical evaluation, workers with conditions that make respirator use unsafe are not identified. Without a written cartridge change schedule, P100 filters may load or breakthrough before the worker notices difficulty breathing; lead exposure may continue at low levels without obvious resistance. The 10-minute video is not adequate training for donning, doffing, seal checks, storage, or limitations. There is also no written respiratory-protection program, no supervisor accountability, and no routine inspection. These gaps matter because the respirator is being used as a primary control at 60 µg/m³, above the PEL. A half-face respirator has an assigned protection factor of 10 only when the program is complete; the program as described does not support that assumption, so the expected protection cannot be approved.
2. Assuming a properly fitted half-face respirator, is the expected protection adequate at 60 µg/m³? What hierarchy-of-controls actions must accompany the respirator use?
Read the worked answer
With an assigned protection factor of 10 and a properly functioning program, the expected workplace exposure would be 60/10 = 6 µg/m³, which is below the 50 µg/m³ PEL. That arithmetic is not a stand-alone approval. The protection factor applies only if fit testing, medical clearance, training, cartridge scheduling, and seal checks are in place; the current program does not meet that condition. More importantly, a respirator is the last line of defense, not a substitute for feasible engineering controls. Lead is a cumulative toxicant, and the blood lead results and abdominal cramps suggest the current exposure is already causing health effects. The plant should implement source controls such as local exhaust at pasting and grid-casting, enclosure of dusty operations, wet methods, HEPA vacuuming, and separation of clean and contaminated areas; administrative controls such as hygiene facilities, change rooms, and no eating in the work area; and medical surveillance with removal criteria. Respirators should continue only as an interim measure while engineering controls are installed and verified.