Worker Protection and Decontamination
Questions here focus on the decontamination sequence, PPE doffing order, and the exposure monitoring logic behind respirator selection.
Decontamination flow
Movement is one-way from dirty to clean: work area, then equipment room where the suit is removed and the respirator is HEPA-vacuumed, then shower, then clean room and street clothes. Workers remove disposable coveralls inside out, bag them as waste, vacuum their boots and respirator, and only then doff the respirator, after leaving the work area. A shower is required for Class I work in a negative pressure enclosure involving 25 linear feet or 10 square feet or more of ACM; where a shower is genuinely infeasible, the employer must document that and provide an equivalent HEPA vacuum and wet wipe decontamination.
PPE and program elements
Disposable coveralls with hood and booties, gloves, eye protection, and a HEPA-filtered respirator fit-tested under a written program. Facial hair at the sealing surface disqualifies a tight-fitting respirator. No eating, drinking, or smoking in the work area; handwashing facilities and clean change areas provided.
Exposure monitoring
Initial representative personal samples for each job classification, then periodic monitoring. A negative exposure assessment can come from objective data, prior monitoring of similar jobs, or documented results showing the PEL was not exceeded, but it must match the actual work conditions and is not permanent.
Worked example
A worker has a 6-hour sample at 0.12 f/cc and a 2-hour sample at 0.03 f/cc. TWA equals (6 x 0.12 + 2 x 0.03) / 8 = (0.72 + 0.06) / 8 = 0.0975 f/cc, just under the 0.1 PEL, so exposure stays within the limit but the margin is thin enough that respirator selection and monitoring frequency deserve a second look.
Traps
Doffing the respirator before the coveralls. Using the clean room as a break room. Monitoring only the least-exposed worker. Treating a negative exposure assessment as valid for every future job.