MRO Magazine

Why it’s important to know your hazardous substances

Hamilton, ON -- A chemical safety program only works if you can identify the chemicals in your workplace, notes the...

Health & Safety

August 1, 2007
By MRO Magazine

Hamilton, ON — A chemical safety program only works if you can identify the chemicals in your workplace, notes the Canadian Centre for Occupational Health and Safety (CCOHS) in Hamilton, Ont.

Consider, for instance, these two recent incidents, CCOHS advises.


It’s not uncommon to find workplaces where a series of pipes, containing propane, bulk oil, compressed air and electrical utilities, are all painted the same colour. Last May, Nova Scotia Environment and Labour issued a hazard alert about this safety hazard, since according to Canada’s Workplace Hazardous Materials Information System (WHMIS), anyone working in the area of a on a pipe needs to know what’s in it, and what safety measures to take if something goes wrong.


When hazardous products are contained or transferred in a pipe, employers must take every reasonable precaution to ensure the safe use, storage and handling of the controlled product. An important part of this is employee education, and the use of colour coding pipes, labels, placards, or any type of identification clearly legible to employees. Nova Scotia provides an example of colour schemes that could be established, and their meaning:

Classification– Colour
Flammable or Explosive– Yellow
Chemically Active or Toxic– Yellow
Extreme Temperatures or Pressures– Yellow
Liquid or Liquid Mixture– Green
Gas or Gaseous Mixture– Blue
Water, Foam, C02, Halon, etc.– Red

Whichever colour scheme is used, employers must post colour code information where everyone can see it and make employees aware of what the colours mean through education and training.


Employees in a plant in Australia were put at risk because no one had identified a contaminant — benzene — would be formed during a chemical process. It happened during a maintenance shutdown. When several sections of the plant were re-opened, a strong odour was detected and it was discovered that there was potential for employees to be exposed to benzene from this byproduct.

Benzene, an extremely flammable chemical that can cause cancer and blood disorders, was one of many chemicals formed as a byproduct of the process. The company had safety procedures in place for such an event, but didn’t implement the procedures because no one had identified the potential for benzene exposure within this area of the process.

Australian occupational health and safety law requires that employers: Ensure that an assessment is made to determine if there is any risk associated with the use of the hazardous substance at the workplace; Ensure that any risk associated with the use of the hazardous substance be eliminated, or reduced as much as possible.

After the incident described above, the company reviewed its chemical processes in all areas of the plant. They identified any other potential intermediates or byproducts that may be harmful to workers, as well as any risks associated with the presence of these substances.

Read the full hazard alerts at the following links:

Labeling of Pipes with Controlled Products – Nova Scotia —

Exposure to Hazardous Substances (by-products) – Victoria, Australia —

Read about the health effects of Benzene from OSH Answers —