Understanding New Hazard Classifications in WHMIS 2015

In today’s installment of our WHMIS series, we will focus on the new chemical classifications mandated by WHMIS 2015 – specifically focusing on biohazardous infectious materials and combustible dust.


What’s new?

Under WHMIS 1988 legislation, chemicals were broken down into six classifications, identified by letters A-F. Some of these classifications also had divisions and subdivisions.

Under WHMIS 2015, things get a little more complicated. WHMIS now categorizes chemicals into two main hazard groups: Physical and Health.  Within each group, there are several hazard classes, and within the classes, chemicals are placed into categories, or types, based on the level of hazard the chemical poses, with “category 1” being the most serious.

*GHS also identifies a third group: Environmental Hazards. This has not been adopted by WHMIS 2015, but may still appear on SDSs.


Biohazardous Infectious Materials

What are ‘biohazardous infectious materials?’

A biohazardous infectious material, as recognized exclusively under WHMIS legislation in Canada, is any material that causes or is known to potentially contribute to the cause of infection, with or without toxicity, in humans and animals. These materials include microorganisms, nucleic acids, and proteins. Examples include blood contaminated with contagious diseases such as HIV, Hepatitis B, salmonella, etc.

Anything categorized into risk Groups 2, 3, and 4 as determined by the World Health Organization (WHO) or the Medical Research Council of Canada are considered to be biohazardous infectious materials.

Unlike the other pictograms included in WHMIS 2015, which have updated to the red diamond-bordered symbols of GHS, biohazardous infectious materials are still identified by their original black-circle-bordered pictogram. This is because GHS does not recognize biohazardous infectious materials – this is a recognized hazard carried over from WHMIS 1988 legislation.

These materials must only be handled while fully protected by the use of appropriate protective equipment.


Combustible Dust

What is ‘combustible dust?’

WHMIS 2015 defines combustible dust as “a mixture or substance that is in the form of finely divided solid particles that, upon ignition, is liable to catch fire or explode when dispersed in air or is classified in a category of the hazard class “Flammable Solids” and 5.0% or more of its composition by weight is a flammable solid and has a particle size ≤ 500µm.”

The following materials have the potential to create combustible dust:

  • Most solid organic materials (such as sugar, flour, grain, wood, etc.)
  • Many metals
  • Some nonmetallic inorganic materials

Many of these materials are not normally combustible, so a thorough inspection should always be completed to determine if combustion is possible.

There is some variance in the definition of combustible dust across countries and even provinces within Canada.

In the United States, combustible dust is defined as, “a solid material composed of distinct particles or pieces, regardless of size, shape, or chemical composition, which presents a fire or deflagration hazard when suspended in air or some other oxidizing medium over a range of concentrations.”

Classification of Combustible Dust

There are currently no regulations or laws for dealing with combustible dust in the United States, while Canadian laws are broken down by federal, provincial, and territorial. This makes dealing with combustible dust more complicated than most hazardous materials.

However, WHMIS 2015 does recognize combustible dust as its own hazard category within the ‘Physical Hazard’ class.

There are many factors that must be considered when evaluating the level of hazard a combustible dust poses. WHMIS 2015 outlines some of them as:

  • The particle size of the dust,
  • The method of dispersion
  • Ventilation system characteristics
  • Air currents
  • Ignition sources
  • Confinement of the dust cloud
  • Physical barriers

The OHSA in the United States outlines the process for determining the hazard of a combustible dust, and suggests the following must be taken into consideration:

  • Anticipated types of operations
  • Uses or downstream material processing that generate dusts should be considered normal conditions of use of a substance. These include operations and uses such as abrasive blasting, cutting, grinding, polishing or crushing of materials; conveying, mixing, sifting or screening dry materials; and the buildup of dried residue from processing wet materials.

Stay tuned to Hazox for more information about WHMIS 2015 regulations. In the next article, we will provide an in-depth, side-by-side comparison of the newly-adopted GHS pictograms, compared to the pictograms of WHMIS 1988.

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