When working in a dangerous area, do you know how many classes of hazardous materials are there? There are different definitions to classify a material as hazardous. This post will explore those definitions and see how we can set an efficient safety strategy to improve the work environment. 

You probably have seen in the industry field signs like this one:

Hazardous Materials how many classes of hazardous materials are there

These signs are for identifying hazardous materials it indicates that the area is dangerous and requires safety measures. However, do you know how these classifications work? The classification is made into nine categories, let’s analyze each of them.

Class 1

Explosives: This category has six sub-categories that classify the level of hazard of the material. 

  • Mass explosive hazard
  • Projection hazard
  • Fire hazard
  • Minor explosion hazard
  • Very Insensitive With Mass Explosion Hazard
  • Extremely Insensitive

Some examples of these materials are fireworks and TNT. Therefore, you will identify this category by those signs below:

Hazardous Materials how many classes of hazardous materials are there

Class 2

Gases: Here we have three sub-categories to classify the level of hazard of the material.

  • Flammable gases
  • Nonflammable gases
  • Toxic gases

So, you can identify each of those by the signs below:

Hazardous Materials how many classes of hazardous materials are there

Class 3

Flammable and combustible liquids: This material presents a hazard when the source of ignition ignites the vapors. Therefore, some examples of this material are:

  • Gasoline 
  • Ethanol
  • Alcohols
  • Ethylene glycol
  • Engine oil

Hazardous Materials how many classes of hazardous materials are there

Class 4

Flammable solids: This category has 3 sub-categories.

  • Flammable Solids
  • Spontaneously Combustible
  • Dangerous When Wet

Some examples of these kinds of materials are oily fabrics, processed metals, and match sticks. Moreover, below are the signs that identify this hazardous material:

Hazardous Materials how many classes of hazardous materials are there

Class 5

Oxidizing Substances, Organic Peroxides: This material is not combustible but it can contribute to increasing combustion in others materials. Meaning that also need to be rated as a hazardous material. In addition, this sign will help you to identify this material presence:

Hazardous Materials how many classes of hazardous materials are there

Class 6

Toxic and Infectious Substances: Here we have different classifications for these similar materials.

  • Toxic substances: more liable to cause lethal harm or serious injury to human health.
  • Infectious substances: more liable to infect by some pathogenic influence.

You will identify this hazardous material by the following sign:

Hazardous Materials how many classes of hazardous materials are there

Class 7

Radioactive: This is a very known material and we all acknowledge its dangerousness. This material requires more measures of safety than any other. But you will see its sign at some medical centers cause some radioactive materials are used in x-ray equipment and even in our daily routine. 

Hazardous Materials how many classes of hazardous materials are there

Class 8

Corrosives: For example of corrosive materials are batteries, sodium hydroxide, and sulfuric acid. Acids can provocate a chemical reaction of melt or damage organic material, also, you will see it in places where is this sign:

Hazardous Materials how many classes of hazardous materials are there

Class 9

Miscellaneous Hazardous Materials: This category embraces all the materials that can’t be rated in the previous eight categories. Mostly is used to list materials that present environmental risks and require care during transportation. For example:

  • Lithium batteries
  • Elevated temperature substances
  • Asbestos

So you will identify this material by the sign below:

Hazardous Materials how many classes of hazardous materials are there

Safety Measures

Now that you how many classes of hazardous materials are there, it’s essential to know how you can control the hazard. At Intrinsically Safe Store, our main goal is to provide intrinsically safe solutions to all the hazardous areas. Indeed, our catalog has a variety of equipment and barriers that will help you to control the hazard and improve intrinsic safety. Finnaly, talk to one of our experts, we are ready to help you!