Editor’s note: For more information on this topic, refer to the AIHA publication Chemical Protective Clothing, from which some of this article is derived.

Personal protective equipment is generally considered a last resort in the hierarchy of controls. By its very nature, PPE implies that the wearer is in proximity to an exposure source, which places him or her at a higher risk for injury in the event of a failure. Still, PPE is an important tool for worker protection and a critical defense-in-depth element. However, when possible, we should use multiple controls to protect workers. This article focuses on work environments that can contaminate PPE surfaces with highly toxic or infectious materials. It also addresses considerations that can help prevent secondary or tertiary exposures, along with ways to mitigate these risks.  The OSHA publication “Personal Protective Equipment” describes PPE as “equipment worn to minimize exposure to a variety of hazards”; examples include “gloves, foot and eye protection, protective hearing devices (earplugs, muffs), hard hats, respirators, and full body suits.” The document provides a general overview of PPE types and describes OSHA’s expectations for employers regarding exposure assessment and the care, donning, and doffing of PPE.  Procedures for decontaminating PPE are discussed in “Occupational Safety and Health Guidance Manual for Hazardous Waste Site Activities,” a 1985 publication of the Department of Health and Human Services. This manual provides the following statement: 
Decontamination methods vary in their effectiveness for removing different substances. The effectiveness of any decontamination method should be assessed at the beginning of a program and periodically throughout the lifetime of the program. If contaminated materials are not being removed or are penetrating protective clothing, the decontamination program must be revised.
That said, simply removing a contaminated component of PPE (without causing secondary exposure) can be just as effective as removing the contaminant from the PPE. THE KEY ELEMENTS OF DECONTAMINATION The decontamination and doffing processes consist of three elements: individuals who wear the ensemble or who assist someone in removing it; procedures or practices; and equipment. A failure in any element can cause unintentional exposures to workers, contractors (for example, through waste or laundry streams), or family members (for example, through infectious diseases).  In terms of the classic industrial hygiene source, pathway, and receiver approach, surface contaminants on PPE ensembles can be killed or neutralized, cleaned or flushed away, or “fixed” to the PPE (for example, by applying water mist) and discarded. Fixing contaminants and discarding the contaminated PPE is also an effective tactic in maintaining continuity of worker protection.
 Considerations for Decontaminating Personal Protective Equipment
CONTINUITY of Protection
Disadvantages of being unacclimatized:
  • Readily show signs of heat stress when exposed to hot environments.
  • Difficulty replacing all of the water lost in sweat.
  • Failure to replace the water lost will slow or prevent acclimatization.
Benefits of acclimatization:
  • Increased sweating efficiency (earlier onset of sweating, greater sweat production, and reduced electrolyte loss in sweat).
  • Stabilization of the circulation.
  • Work is performed with lower core temperature and heart rate.
  • Increased skin blood flow at a given core temperature.
Acclimatization plan:
  • Gradually increase exposure time in hot environmental conditions over a period of 7 to 14 days.
  • For new workers, the schedule should be no more than 20% of the usual duration of work in the hot environment on day 1 and a no more than 20% increase on each additional day.
  • For workers who have had previous experience with the job, the acclimatization regimen should be no more than 50% of the usual duration of work in the hot environment on day 1, 60% on day 2, 80% on day 3, and 100% on day 4.
  • The time required for non–physically fit individuals to develop acclimatization is about 50% greater than for the physically fit.
Level of acclimatization:
  • Relative to the initial level of physical fitness and the total heat stress experienced by the individual.
Maintaining acclimatization:
  • Can be maintained for a few days of non-heat exposure.
  • Absence from work in the heat for a week or more results in a significant loss in the beneficial adaptations leading to an increase likelihood of acute dehydration, illness, or fatigue.
  • Can be regained in 2 to 3 days upon return to a hot job.
  • Appears to be better maintained by those who are physically fit.
  • Seasonal shifts in temperatures may result in difficulties.
  • Working in hot, humid environments provides adaptive benefits that also apply in hot, desert environments, and vice versa.
  • Air conditioning will not affect acclimatization.
Acclimatization in Workers