Personal Protective Equipment and Decontamination
Technicians must select, inspect, don, and work in chemical protective clothing correctly. Know the four EPA levels: Level A (fully encapsulating suit with SCBA, highest vapor protection), Level B (SCBA with chemical-resistant clothing, highest respiratory protection but less vapor protection), Level C (air-purifying respirator with appropriate clothing), and Level D (work uniform, no respiratory protection). Understand permeation, penetration, and degradation as distinct failure modes, and that selection depends on the chemical's specific data, not the suit's color or generic claims. Respiratory protection requires fit testing, medical clearance, and awareness of IDLH and oxygen-deficient atmospheres where only positive-pressure SCBA or supplied air is acceptable.
Decontamination concepts: establish a contamination reduction corridor with hot, warm, and cold zones; perform gross, secondary, and technical decon; contain runoff; protect the decon team; and treat all entry team members and equipment as contaminated until decon is complete. Questions often test the difference between emergency decon (immediate, life-safety driven) and technical decon, and the need to avoid cross-contamination in the cold zone.
Traps: assuming Level B is safe for all vapors; using air-purifying respirators in unknown or IDLH atmospheres; forgetting that permeation may not be visible; and skipping decon for equipment.
Rule of thumb: unknown chemical or IDLH condition means Level A or B with positive-pressure SCBA - never an air-purifying respirator.
Worked example: An unknown liquid with visible off-gassing and no monitoring data requires Level A entry, a decon corridor, and runoff containment before anyone crosses the hot line.