Hazard Materials represent substances — which may be natural or man-made — that are inherently dangerous or pose a safety hazard. Examples include materials which are explosive, poisonous, chemically active (including acids and other corrosives), radioactive, or biologically active (including human blood and other medical waste).

Hazmat teams are specially trained to handle such dangerous materials.

In the United States, dangerous goods are often indicated by diamond-shaped signage on the item (see NFPA 704), its container, or the building where it is stored.


The United States Department of Homeland Security defines a hazmat suit (hazardous materials suit) as “an overall garment worn to protect people from hazardous materials or substances, including chemicals, biological agents, or radioactive materials.”

More specifically, hazmat suits are used by the following:

  • Firefighters
  • Emergency medical technicians
  • Paramedics
  • Researchers
  • Toxic spill workers
  • Contamination clean-up specialists

These suits are worn as personal protective equipment (PPE) that consist of an impermeable whole-body garment to provide security against hazardous materials and are often combined with self-contained breathing apparatus (SCBA) to ensure a supply of breathable air.

More generally, hazmat suits may provide protection from:

  • Chemical agents
  • Nuclear agents
  • Biological agents
  • Fire/high temperatures

Working in a hazmat suit can be strenuous, as the suits tend to be less flexible than conventional work garments. With the exception of laboratory versions, hazmat suits can be hot and poorly ventilated (if at all). Therefore, use is usually limited to short durations of up to 2 hours, depending on the difficulty of the work.

Hazmat protective clothing is classified as any of Level A, B, C, or D, based upon the degree of protection they provide.

The highest level of protection against vapors, gases, mists, and particles is Level A, which consists of a fully encapsulating chemical entry suit with a full-facepiece self-contained breathing apparatus (SCBA). A person must also wear boots with steel toes and shanks on the outside of the suit and specially selected chemical-resistant gloves for this level of protection. The breathing apparatus is worn inside (encapsulated within) the suit. To qualify as Level A protection, an intrinsically safe two-way radio is also worn inside the suit, often incorporating voice-operated microphones and an earpiece speaker for monitoring the operations channel.

Level B protection requires a garment (including SCBA) that provides protection against splashes from a hazardous chemical. Since the breathing apparatus is sometimes worn on the outside of the garment, Level B protection is not vapor-protective. Level B suits can also be fully encapsulating, which helps prevent the SCBA from becoming contaminated. It is worn when vapor-protective clothing (Level A) is not required. Wrists, ankles, facepiece and hood, and waist are secured to prevent any entry of splashed liquid. Depending on the chemical being handled, specific types of gloves and boots are donned. These may or may not be attached to the garment. The garment itself may be one piece or a two-piece hooded suit. Level B protection also requires the wearing of chemical-resistant boots with steel toes and shanks on the outside of the garment. As with Level A, chemical-resistant gloves and two-way radio communications are also required.

Level C protection differs from Level B in the area of equipment needed for respiratory protection. The same type of garment used for Level B protection is worn for Level C. Level C protection allows for the use of respiratory protection equipment other than SCBA. This protection includes any of the various types of air-purifying respirators. People should not use this level of protection unless the specific hazardous material is known and its concentration can be measured. Level C equipment does not offer the protection needed in an oxygen deficient atmosphere.

Level D protection does not protect the person from chemical exposure. Therefore, this level of protection can only be used in situations where a person has no possibility of contact with chemicals. A pair of coveralls or other work-type garment along with chemical-resistant footwear with steel toes and shanks are all that is required to qualify as Level D protection. Most firefighter turnout gear is considered to be Level D.


As defined by the United Nations, there are nine separate classes of hazardous materials, which include:

Class 1 – Explosives

Class 2 – Gases

Class 3 – Flammable Liquids

Class 4 – Flammable Solids

Class 5 – Oxidizing Substances and Organic Peroxides

Class 6 – Toxic Substances and Infectious Substances

Class 7 – Radioactive Materials

Class 8 – Corrosive Substances

Class 9 – Miscellaneous Hazardous Materials


The first level of response for firefighters is education to increase awareness. Classes and certifications at the awareness and operations levels allow firefighters to anticipate potential chemical threats and initiate a safe reaction for civilians and first responders.

While the first education level provides firefighters enough information to recognize a hazmat situation and not become part of the problem, the next level, operations, extends their knowledge to initiate a more aggressive response requiring basic protection and identification equipment designed for an indirect and non-contact mitigation. Observation, evaluation and supply management become the initial focus of an operations command.

The third tier of hazmat education for firefighters is the technician level. Requiring more hands-on training and the use of increased protection and identification equipment; a hazmat technician is capable of safely and appropriately interacting with a chemical breach. They initiate positive identification, risk/benefit analysis, mitigation and containment tactics, as well as present recommendations for a final strategic resolution.

Hazmat technician level firefighters have saved lives, stabilized environmental locations and eliminated numerous potential hazmat threats before they began.

Every time a first responder enters a burning building, approaches a vehicle accident, or answers a medical emergency call, they could encounter hazardous materials.

As a result, hazmat response has become another critical incident category for the fire service, which requires its own measured, deliberate and intensive approach.

Hazardous Materials and Hazmat Suits
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