Reference Manual for the WHMIS Requirements of the Hazardous Products Act and Controlled Products Regulations

CPR Section 5 - Complex Mixtures

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Complex Mixtures

Interpretation / Discussion of Section 5

In this section, cut-off concentrations are established for ingredients that are complex mixtures. The term "complex mixture" is defined in section 2 of the CPR. Turpentine, petroleum distillates and atmospheric air are examples of complex mixtures. A complex mixture can be comprised of a multitude of ingredients whose concentrations may vary from batch to batch. A synthetic mixture of gases which approximates the composition of atmospheric air does not fit the definition of a complex mixture because it is not naturally occurring. Therefore, for such a mixture, the MSDS must disclose the ingredients in accordance with Section 13(a) of the HPA.

Requirement to Disclose the Identity of a Complex Mixture: The intent of the CPR is that, subject to cut-offs, etc., the MSDS discloses the identity of all complex mixtures contained in the controlled product.

When WHMIS was being developed, WHMIS participants raised the issue of the common use of complex mixtures in "pure" form and as components of various products. Although these complex mixtures made up a significant portion (if not all) of a product, often many ingredients of the complex mixture would be present below cut-off concentrations in the final product.

As the composition of complex mixtures often varies, if normal ingredient disclosure requirements applied, extensive testing would have to be undertaken on the part of the supplier. Also, if normal ingredient disclosure requirements applied to complex mixtures, in many cases only a minor portion of the overall complex mixture would have to be disclosed. Had the cut-offs established in section 4 of the CPR applied to a product which contained, for example, 30% turpentine and the most abundant single ingredient in the turpentine was n-heptane at 3% (i.e., 0.9% of the total product consisted of n-heptane), a supplier would not be required to disclose any ingredient information in respect of a substance which constitutes 30% of the product. Furthermore, it was recognized that in a significant number of cases, toxicological studies as well as physical tests were conducted and results were only available for the complex mixture--not its individual ingredients.

As a compromise, it was agreed that the generic name of a complex mixture could be disclosed in place of the ingredients of the complex mixture but that the concentration cut-offs established in section 4 would not apply to complex mixtures or a component that was a complex mixture.

A complex mixture will likely contain numerous ingredients. The supplier has the option of:

• disclosing the name and concentration of the complex mixture; or
  
• disclosing the names and concentrations of all the ingredients of the complex mixture, even if the concentrations of each ingredient is below the applicable cut-off for single ingredients specified in section 4, i.e. below 0.1% or 1%, whichever is applicable.

Since the concentration cut-offs established in section 4 do not apply to "a complex mixture or a component of a controlled product that is a complex mixture", if the supplier does not take advantage of the exemption in subsection 5(2), the supplier cannot apply the cut-off established in section 4 in relation to the ingredients of the complex mixture. Although hypothetically possible, in practical terms, it is impossible to disclose all ingredients if there is no cut-off limit. Therefore, as the second choice is neither a pragmatic nor a realistic "option", the MSDS must disclose the identity of all complex mixtures in the controlled product.

Requirement to Associate Individual Ingredients with a Complex Mixture: Suppliers wishing to use a single MSDS in the marketing of their products in Canada and the United States (U.S.) may have to disclose certain chemicals comprising a complex mixture in order to respect individual U.S. state laws. If individual ingredients of a complex mixture are disclosed, the MSDS should clearly identify which of the disclosed ingredients are components of the complex mixture (or specify which ingredients are components of which complex mixture if there is more than one complex mixture in the controlled product). As stated above, the MSDS must still disclose the identity of all complex mixtures contained in the controlled product.

Subsection 5(1) and Paragraph 5(2)(c):

In the case of a controlled product comprised of 100% of a complex mixture (e.g. pure turpentine), the commonly known generic name for the complex mixture may be disclosed on the MSDS in lieu of the names of the individual ingredients of the complex mixture. When a complex mixture is a component of a controlled product (e.g. a controlled product that is a solution containing 5% turpentine), the generic name of the complex mixture and its concentration can also be disclosed in lieu of the chemical identity and concentration of the ingredients of the complex mixture.

Paragraphs 5(2)(a) and (b):

Complex mixtures that are teratogens, embryotoxins, carcinogens, reproductive toxins, respiratory tract sensitizers or mutagens and found in a concentration of less than 0.1% (weight/weight) do not have to be disclosed on the MSDS. Any other complex mixture included in the hazard criteria does not need to be disclosed if its concentration is less than 1% (weight/weight) unless the complex mixture is on the IDL and the concentration specified on the IDL for that complex mixture is 0.1% (weight/weight).