PPE Use & Selection
Personal protective equipment is the last line of defense when hazards cannot be fully removed by engineering or work-practice controls. This chapter explains the EPA levels of protection, the main types of respirators, and why every piece of PPE has limits that must be respected.
EPA Levels A Through D
The EPA describes four levels of protection that combine respiratory and skin protection. Level A gives the highest protection for both, using a fully encapsulating vapor-tight suit with SCBA, and is chosen when high or unknown skin-hazardous vapors may be present. Level B keeps the highest respiratory protection but less skin protection, Level C uses an air-purifying respirator when the contaminant and concentration are known, and Level D is basic work clothing for sites with no expected inhalation or skin hazard. Selecting the right level means matching protection to the characterized hazard.
Respiratory Protection Types
Respirators fall into two broad families. Air-purifying respirators (APRs) filter the surrounding air through cartridges or filters and are limited to atmospheres with enough oxygen, a known contaminant, and a matching cartridge. Supplied-air respirators (SARs) deliver clean air through a hose from a remote source, while self-contained breathing apparatus (SCBA) carries its own air supply on the worker. SARs and SCBA are required for oxygen-deficient, IDLH, or unknown atmospheres where an APR would be unsafe.
Chemical-Protective Clothing and Its Limits
No single suit or glove resists every chemical. Materials differ in how they stand up to permeation (chemical passing through at the molecular level), degradation (material breaking down), and penetration (leakage through seams or zippers). Selection uses compatibility charts and breakthrough-time data matched to the specific chemicals expected on site. Recognizing that PPE can fail keeps a worker from over-trusting a suit and reminds the team to inspect equipment before every use.
Donning, Doffing, and Heat Stress
Putting on (donning) and removing (doffing) PPE follow deliberate procedures, because the highest risk of self-contamination often comes during removal when a worker can touch the dirty outer surface. Doffing is usually done within a decontamination line so contamination stays away from skin and clean clothing. Impermeable suits also trap body heat, so heat stress is a real hazard that calls for work-rest cycles, hydration, and monitoring. Practicing donning and doffing during training builds the muscle memory that protects workers in the field.