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CAS Registry Number 3555-47-3

Trisiloxane, 1,1,1,5,5,5-hexamethyl-3,3-bis[(trimethylsilyl)oxy]-, also known as M4Q, is an industrial chemical.

M4Q occurs as a reaction by-product (left over from manufacturing processes) of a range of silicon-based products, including paints, coatings, and cosmetics including some personal care products.
This substance is not manufactured in Canada but is imported into Canada as an impurity in end products.

Prior to assessment, M4Q was identified as a potential concern to the environment based on information regarding possible persistence, accumulation in organisms and potential to cause harm to organisms.
M4Q was not considered to be a high priority for assessment of potential risks to human health; however, potential health effects were also evaluated in this screening assessment.

Most releases of this substance to the environment are through disposal to landfills or incineration during industrial and consumer use.
Some releases of this substance to wastewater and air are also predicted.

The general population of Canada may be exposed to M4Q through inhalation of air.
Canadians may also be exposed to M4Q during the use of paints, coatings, and cosmetics including some personal care products containing by-products of this substance; however, these exposures are expected to be low.

The Government of Canada has conducted a science-based evaluation of M4Q called a screening assessment.
Screening assessments address potential for harm to the general population (not including workplace exposures) and the environment.
Results of the draft screening assessment indicate that although M4Q has the potential to remain in the environment for a long time, it is not expected to accumulate in organisms.
Furthermore, the quantity of M4Q that may be released to the environment is below the level expected to cause harm to organisms.
The Government of Canada is therefore proposing that M4Q is not entering the environment in a quantity or under conditions that constitute a danger to the environment.
The Government of Canada is also proposing that M4Q is not considered to be harmful to the health of the general population at current levels of exposure.

If the proposed conclusion is confirmed in the final screening assessment, the Government of Canada proposes that no further action be taken on M4Q.
The draft screening assessment report was published on January 8, 2011 and will be followed by a 60-day public comment period (from January 8, 2011 to March 9, 2011).

The health risks associated with a chemical depend on the hazard (its potential to cause health effects) and the dose (the amount of chemical to which you are exposed). M4Q is not a concern for the environment or human health at current levels of exposure.
As a general precaution, Canadians are reminded when using any product to carefully follow any safety warnings and directions.
Canadians who handle M4Q in the workplace should consult with their occupational health and safety representative about safe handling practices, applicable laws and requirements under the Workplace Hazardous Materials Information System (WHMIS).