What are hazardous materials?
Hazardous materials, hazardous substances and hazardous waste all have different meanings and are often times misused terms. The primary difference between these terms is the intended usage of the material. If the material is intended to be used and is hazardous it is a hazardous material; if it is intended for disposal it is a hazardous waste.
The term, hazardous materials, was first defined by USDOT in 1975 as a substance or material which has been determined by the Secretary of Transportation to be capable of posing an unreasonable risk to health, safety and property when transported. This definition is transportation related. Therefore, you will always see a placard or sign placed on vehicles carrying these materials.
Hazardous substances are defined by EPA, DOT and OSHA and is any material that can produce an adverse effect on the health of safety of the person exposed. These substances are listed in section 101(14) and 101(33) of CERCLA and 49 CRF 172.101.
Hazardous waste is any waste material which is ignitable, corrosive, reactive or toxic and which may pose a substantial or potential hazard to human health and safety and to the environment when improperly managed.
The abbreviation, hazmat, is short is used for any hazardous material or materials that may pose unreasonable risks to health, safety, property or the environment when used, transported, stored or disposed of.
The DOT uses a classification and marking system to help identify hazardous materials being transported to assist officials with managing accidents and spills.
Hazard classes and UN markings
A. Packages containing dangerous goods must be durably marked with the correct technical name and with distinctive labels or stencils of the labels.
B. The International Maritime Organization (IMO), which is a branch of the United Nations (UN), classifies dangerous goods into nine hazard classes. Diamond labels denote the hazards involved by means of colors and symbols.
C. Some hazard classes are further subdivided into hazard divisions due to their wide scopes.
There are nine (9) hazard classes: Their order does not indicate degree of danger.
- Explosives - This class has six divisions; in addition, this class has 13 compatibility groups that identify the kind of explosive articles and substances that are deemed to be compatible, which is very important when handling this type of cargo.
- Gases - This class comprises compressed gases, liquefied gases, gases in solution, and mixtures of one or more gases with one or more vapors of substances of other classes. This class is organized into three subdivisions based on the primary hazards of gases during transport.
- Flammable liquids
- Flammable solids
- Oxidizers and organic peroxides
- Toxic materials and infectious substances
- Radioactive materials
- Miscellaneous dangerous goods