5.1 EPA/OSHA PPE Ensembles: Levels A, B, C, and D

5.1 EPA/OSHA PPE Ensembles: Levels A, B, C, and D

When conducting hazardous waste operations or emergency response, the selection of Personal Protective Equipment (PPE) is arguably one of the most critical safety decisions. The EPA and OSHA have standardized PPE ensembles into four distinct categories: Levels A, B, C, and D. These levels provide a structured framework for matching the degree of protection to the specific hazards present at a site, taking into account respiratory, skin, and eye protection needs. Understanding the nuances of each level, as well as the criteria for upgrading or downgrading, is essential for maintaining worker safety.

Level A Protection

Level A protection is required when the highest level of respiratory, skin, and eye protection is necessary. This is the maximum protection available and is typically deployed when the chemical hazards are unknown, the atmosphere is Immediately Dangerous to Life or Health (IDLH), or there is a high potential for splash, immersion, or exposure to unexpected vapors, gases, or particulates that can rapidly permeate the skin.

The core of the Level A ensemble is the Totally Encapsulating Chemical Protective (TECP) suit. OSHA does not require third-party certification of the suit itself — Appendix B to 1910.120 simply describes the ensemble, and 1910.120(g)(4) sets performance and inspection duties — but the vapor-protective suits sold for Level A work are normally certified to the NFPA vapor-protective ensemble requirements historically published as NFPA 1991 and, since the 2022 edition, consolidated into NFPA 1990, Standard for Protective Ensembles for Hazardous Materials and CBRN Operations. This suit encapsulates the worker completely, including their breathing apparatus. The respiratory protection must consist of a positive-pressure, full-facepiece Self-Contained Breathing Apparatus (SCBA) or a positive-pressure Supplied-Air Respirator (SAR) equipped with an escape bottle. In addition to the suit and SCBA, workers must wear inner chemical-resistant gloves, outer chemical-resistant gloves, and chemical-resistant boots with a steel toe and shank. Hard hats are often worn inside the suit for impact protection. Level A is mandatory when dealing with unknown substances in a confined space or when skin-absorbable hazardous vapors are present in high concentrations.

Level B Protection

Level B protection provides the highest level of respiratory protection but a lesser degree of skin protection compared to Level A. It is the minimum level of protection recommended for initial site entries where the hazards have not yet been fully identified.

Like Level A, Level B requires maximum respiratory protection: a positive-pressure, full-facepiece SCBA or a positive-pressure SAR with an emergency escape cylinder. However, the skin protection differs. Instead of a totally encapsulating suit, workers wear a liquid-splash protective suit — the class of garment historically covered by NFPA 1992 and now consolidated, along with NFPA 1991 and NFPA 1994, into NFPA 1990 (2022). This could be a multi-piece chemical suit, coveralls, or a hooded chemical-resistant suit. Chemical-resistant inner and outer gloves, as well as steel-toe chemical-resistant boots, are also required. Level B is utilized when the atmospheric concentration of a contaminant is IDLH, or the oxygen level is below 19.5%, but the chemicals present do not pose a severe skin vapor absorption hazard. The primary difference between Level A and Level B is the threat to the skin from vapors.

Level C Protection

Level C protection is utilized when the airborne contaminants are known, their concentrations have been measured, and the criteria for using an Air-Purifying Respirator (APR) or Powered Air-Purifying Respirator (PAPR) are met. Importantly, Level C cannot be used in IDLH atmospheres or when the ambient oxygen concentration falls below 19.5%.

The respiratory protection in Level C consists of a full-facepiece or half-mask APR or PAPR equipped with appropriate NIOSH-approved filters or cartridges specific to the known contaminant. The skin protection is similar to Level B, involving chemical splash suits, chemical-resistant inner and outer gloves, and chemical-resistant steel-toe boots. Level C is common during the remediation phase of a project after the site has been thoroughly characterized and continuous air monitoring confirms that exposure levels remain well within the operational limits of the respirators being used. The use of Level C requires strict adherence to respirator cartridge change-out schedules.

Level D Protection

Level D is essentially a standard work uniform and provides absolutely no respiratory protection and minimal skin protection. It is used only when the atmosphere contains no known hazards and work functions preclude splashes, immersion, or the potential for unexpected inhalation of or contact with hazardous levels of any chemicals.

A typical Level D ensemble consists of standard coveralls or a work uniform, safety glasses or chemical splash goggles, a hard hat, and safety boots or shoes with a steel toe and shank. Optional equipment might include standard work gloves or hearing protection depending on the physical hazards of the site (e.g., heavy machinery operation). Level D cannot be worn on any site where chemical exposure above permissible limits is a possibility.

Criteria for Upgrading and Downgrading PPE

The selection of a PPE level is not static; it must be continuously evaluated against real-time site conditions. An upgrade in PPE (e.g., moving from Level C to Level B) is required when:

• Known or suspected hazard concentrations increase.
• The oxygen concentration falls below 19.5%.
• Unidentified contaminants are detected during air monitoring.
• Work tasks change, increasing the risk of splash or direct contact.
• Temperature or weather conditions alter the volatility of site chemicals.

Conversely, downgrading PPE (e.g., moving from Level B to Level C) may be authorized by the Site Safety and Health Officer (SSHO) only when:

• Comprehensive air monitoring confirms that contaminant concentrations have decreased and stabilized below limits requiring higher protection.
• The oxygen level is verified to be at or above 19.5%.
• The risk of skin contact or liquid splash has been significantly minimized.
• The specific chemicals and their exact concentrations are definitively known.

Summary Decision Matrix