WHMIS Classification: State Matters

When classifying a mixture, several criteria must be considered. Adding up the hazards of each ingredient is not enough. The classification of a mix is much more complex than the simple addition of its constituent parts. We need to go beyond simply enforcing regulations. We should perform physical tests to support our decisions. Ask yourself: Did my ingredients react? Has neutralization occurred? Is substance X still bioaccessible?

What exactly is the concept of bioaccessibility?

Consider titanium dioxide (TiO2) as an example. This substance is widely used as a white pigment in various industries. This substance is classified as a suspected carcinogen (Category 2) when in powder form, only if inhalation is a potential risk. In this case, the classification of the substance is contingent on the possibility of inhalation.

Let’s mix our pigments with liquids or resins to make a paste, paint or even toothpaste. During this process, the pigment was completely incorporated, and the powder was well coated.

As per the regulations, if the substance’s concentration exceeds the threshold limit for a particular category, the mixture will be categorized. However, our paint does not meet the conditions required for classifying titanium dioxide, because no particles of this substance will remain in the air, and therefore the risk of inhaling them has disappeared. In this situation, our paint or toothpaste will not be considered carcinogenic, as titanium dioxide is no longer bioaccessible. However, if you prepare an SDS (Safety Data Sheet), you will have to list the ingredient without classifying it.

Why maintain this categorization if the advertised goods are non-carcinogenic?

The answer is to protect the health of workers who handle the raw material in powder form during the manufacturing of your finished products. In fact, if I only have titanium dioxide in powder form, it is possible for the dust particles to be inhaled, meeting the necessary criteria. Therefore, it is crucial for employees to be aware of the dangers associated with working with chemicals. This knowledge will enable them to use appropriate personal protective equipment, protecting their health both in the short and long term.

For more information or help with your classification, do not hesitate to contact us at 450 906-6999.