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What Are the Levels of HAZMAT and What Are They Used For?

By Steve Prentice
Published: September 20, 2019
Key Takeaways

Knowing HAZMAT levels allows you to classify hazardous materials according to their risks, emergency incidents according to their severity, and protective clothing according to the degree of protection they offer.

There is sometimes a bit of confusion about the term HAZMAT. In no small part, that's because it has three different standard applications.

First and foremost, HAZMAT stands for "hazardous materials" and refers to items in any state (solid, liquid, or gas) that have the potential to cause harm to people or the environment.

The term HAZMAT is also commonly used to refer to the protective suits worn by people whose work places them in contact with hazardous materials. HAZMAT suits can be worn by people in fire services, emergency services, environmental services, or national security departments.


Finally, HAZMAT can be used to describe the severity of an incident.

Various classifications and groupings are applied for all these different uses of the term and are shared with all people and organizations who might come into contact with hazardous materials.

(See 7 Things to Know About Storing Hazardous Materials for related reading.)

In this article, we'll take a look at each use of the term HAZMAT and go over the different levels that apply to each.

HAZMAT Materials Levels

In many countries (including the United States, Canada, and within Europe), hazardous materials are identified by color-coded and numeric diamond-shaped placards or stickers affixed to their containers, transporters, and storage equipment.

The levels are divided into nine classes, each with subcategories that further define the risk. Specific instruction regarding handling and emergency response are to be clearly identified and readily available wherever these products are located.

(Learn more in Tips for Handling and Storing Chemical Drums.)

Please note that not all countries subscribe to this specific categorization system, so it is vital to review HAZMAT labeling conventions in any country that you are visiting or doing business with.

The materials are categorized as follows:

  • Class 1: Explosives
  • Class 2: Flammable Gas
  • Class 3: Flammable Liquids
  • Class 4: Flammable Solids
  • Class 5: Oxidizing Agents and Organic Peroxides (these create oxygen during reaction, making them a combustion threat)
  • Class 6: Toxic and Infectious Substances
  • Class 7: Radioactive Substances
  • Class 8: Corrosive Substances
  • Class 9: Miscellaneous (ranging from asbestos to self-inflating life rafts)

Each of these classes is further broken down into subcategories, numerically identified as a decimal place of its class. For example, the subcategories for Class 1 (Explosives) are as follows:

  • 1.1: Explosives with a mass explosion hazard (nitroglycerin/dynamite)
  • 1.2: Explosives with a blast/projection hazard
  • 1.3: Explosives with a minor blast hazard (rocket propellant, display fireworks)
  • 1.4: Explosives with a major fire hazard (consumer fireworks, ammunition)
  • 1.5: Blasting agents
  • 1.6: Extremely insensitive explosives

The numerical system of HAZMAT levels is used at all points related to the handling of the product or substance, from manufacture to sale, transport, safe usage, and emergency management.

Protection Levels for HAZMAT Workers

Another vital demarcation for hazardous materials relates to the protection needed for the people who work with them. OSHA defines four HAZMAT worker protection levels, identified by the letters A, B, C, and D.

Level A offers the most protection against hazardous materials, while Level D offers the least. The materials being used, and the status of any working situation (level of emergency or risk, for example), must be registered in a site-specific Health And Safety Plan (HASP). Workers will then be assigned the appropriate level of protection.

Level A

Level A uses full physical isolation combined with full body and respiratory protection. This involves a vapor protection suit with positive pressure, meaning that air is pumped into the suit so that air will expel outward in case of a puncture, preventing infectious substances from entering the suit.

Level A protection also includes a full-face Self-Contained Breathing Apparatus (SCBA), chemical resistant gloves, chemical resistant safety boots, and two-way radio communication.

(Learn more in SCBA 101 - Meet the Respirator that Will Save Your Life.)

Level B

Level B protection is similar to Level A, except that the full body suit provides liquid splash protection but no protection against vapors.

Level C

Level C protection is the norm for most workers who work with hazardous materials in non-emergency situations. During normal operations, hazardous materials levels are kept within the Permissible Exposure Limits (PELs) established by OSHA and Level C protection is sufficient for concentrations within these limits.

Level C requirements include full facepiece including an air-purifying, canister-equipped respirator, as well as safety boots, chemical-resistant gloves, two-way communications system, and hard hat.

(Learn more about Chemical-Resistant Glove Materials.)

Level D

Level D protection is typical construction site gear. It includes coveralls, safety boots, glasses, and hard hat.

Emergency Response Levels

Classifications of HAZMAT-related situations are required by law in most countries and they assist in safe and efficient manufacture, usage, transportation, and disposal of hazardous materials.

The classification system is also extremely useful in situations where multiple materials are involved, for example, numerous chemicals being used in a manufacturing process, or even being stored or transported in close proximity.

As recorded by the National Fire Protection Association:

  • A Level 1 incident “involves hazardous materials that can be contained, extinguished, and/or abated using immediately available public sector responders having jurisdiction.”
    • Level 1 incidents present little risk to the environment and to public health with containment and cleanup.
  • A Level 2 incident involves “hazardous materials beyond the capabilities of the first responders on the scene and could be beyond the capabilities of the public sector responders having jurisdiction.”
    • These incidents can pose immediate and long-term risk to the environment and public health and may need state- or federal-level level emergency assistance.
  • A Level 3 incident involves hazardous materials “beyond the capabilities of a single state or regional response team and requires additional assistance."
    • These incidents generally pose extreme, immediate, or long-term risk to the environment and public health.


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Written by Steve Prentice

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Steve Prentice is a project manager and a specialist in productivity and technology in the workplace. Much of his work focuses on techniques for creating and maintaining safe and healthy working environments. He believes new educational technologies will go a long way in establishing policies and practice that support safe and balanced work, while blockchain tech will assist greatly in the process, and he assists companies in adopting these as new best practices. He is a published author of three self-help books, and is in high demand as a guest speaker and media commentator. His academic background is in organizational psychology and project management.

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