HAZMAT Suits - OSHA Protection Levels

HAZMAT Suits - OSHA Protection LevelsHAZMAT Suit Levels - OSHA Required

How Does a HAZMAT Suit Work?

A HAZMAT (Hazardous Materials) suit is a body garment designed to protect a person against dangerous environments and hazardous substances. These differ in fabric type based on the level of protection from a particular hazardous substance(s) or group of hazardous substances. These suits are often used by first responders or authorized personnel cleaning up contaminated facilities and performing work in hazardous environments. The suits are expensive, well constructed and serve their intended purpose of keeping an individual safe from hazardous environments and toxic atmospheres.

Depending on the level (see below), HAZMAT suits can provide protection from Chemical, Biological, Radiological and Nuclear (CBRN) agents. Level A suits are fully encapsulating to ensure the user will not come into direct contact with or inhale hazardous substances. They can offer different ways of supplying air to the wearer to ensure they are breathing fresh, uncontaminated air. Usually, a self-contained breathing apparatus (SCBA) can be enclosed within the suit or attached to the suit.

As listed in the Occupational Safety and Health Administration (OSHA) Title 29 Code of Federal Regulations (CFR) 1910.120 Appendix B, HAZMAT suits are rated by different levels based on the protection they afford a wearer. The levels range from A-D with A being the most complex ensemble of the levels. It is also provides the most protection.


The Level A ensemble is needed when the highest level of protection of exposure to chemicals and hazardous substances is present. Commonly referred to as the "moon suit". A fully encapsulating garment that completely envelops a person. This level affords protection against solids, liquids, mists, vapors and gases. A person would typically don this equipment when hazards have been identified and there is a substantial risk of exposure to hazardous substances. However, this level of protection is also required for work areas where hazards have not been fully identified. A Self Contained Breathing Apparatus (SCBA) is typically worn with this ensemble. But a positive pressure supplied air respirator with an escape SCBA can be utilized as well. This level can be used in oxygen deficient atmospheres of less than 19.5 percent oxygen. The required equipment for Level A protection consists of a fully encapsulating suit, SCBA or other similar respirator, inner and outer chemical resistant gloves, two way radio, and chemical resistant boots. Other equipment such as cooling vests can be included based upon the work location and the conditions.


When a high level of respiratory protection is needed, but skin protection can be lower, Level B suits are required. These suits are worn with an SCBA, either inside or outside depending on whether the suit is encapsulating or not. They safeguard against splashes of hazardous materials but not against vapors or gases. To use Level B respiratory protection, an SCBA or positive-pressure supplied air respirator with an escape SCBA is necessary. The attire should also include chemical-resistant clothing, gloves, and steel-toe and midsole boots. The difference between Level A and Level B is primarily the degree of skin protection. This level can be used in environments with less than 19.5 percent oxygen.


Level C protection can be used when the oxygen content is at least 19.5 percent and when the airborne contaminants (concentration and type) have been identified. Level C is for protection against known hazardous substances, but not chemical emergency situations or potentially oxygen-deficient environments. It is the most used level of protection as remediation of most contaminated sites require at least this type of equipment. The equipment for this level of protection consists of an outer protective garment (splash suit - Tyvek®), air purifying respirator, chemical resistant gloves and boots, two way radio and hard hat.


The Level D protective gear is a basic work uniform designed to provide limited protection. We did not include a photo of the ensemble as it really is not a HAZMAT suit. It is utilized in work environments where there are no known hazards, and the work process does not involve exposure to splashes, immersion, inhalation, or direct contact with dangerous chemicals. The Level D ensemble does not require any respiratory protection, and only minimal skin protection is necessary. The gear includes coveralls, safety boots or shoes, and safety glasses or chemical splash goggles. 

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U.S. Occupational Safety and Health Administration