Trisiloxane, 1,1,1,5,5,5-hexamethyl-3,3-bis[(trimethylsilyl)oxy]- (M4Q)

Trisiloxane, 1,1,1,5,5,5-hexamethyl-3,3-bis[(trimethylsilyl)oxy]-
CAS Registry Number 3555-47-3

What is it?

  • Trisiloxane, 1,1,1,5,5,5-hexamethyl-3,3-bis[(trimethylsilyl)oxy]-, also known as M4Q, is an industrial chemical. It is not expected to occur naturally in the environment.

How is it used?

  • M4Q is formed as a reaction by-product (left over from manufacturing processes) in adhesives, paint and coating additives, and cosmetics including some personal care products.
  • This substance is not manufactured in Canada but is imported into Canada as an impurity in end-use products.

Why is the Government of Canada assessing it?

  • 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.

How are Canadians exposed to it?

  • Exposure of the general population of Canada to M4Q may occur during the use of paints, coatings, and cosmetics, including some personal care products.

How is it released to the environment?

  • Releases of M4Q to the environment may occur during processing, transportation and storage of the substance, as well as during service life and disposal of products containing M4Q.
  • Most releases of M4Q are expected to be to landfill and wastewater.

What are the results of the assessment?

  • The Government of Canada has conducted a science-based evaluation of M4Q, called a screening assessment.
  • Screening assessments address the potential for harm to the general population of Canada and the environment.
  • Results of the final screening assessment indicate that M4Q has the potential to remain in the environment for a long time and accumulate in organisms.
  • However, 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 has therefore concluded that M4Q is not entering the environment in a quantity or under conditions that constitute a danger to the environment.
  • The Government of Canada has also concluded that M4Q is not harmful to the health of the general population at current levels of exposure.
  • Hazards related to chemicals used in the workplace should be classified accordingly under the Workplace Hazardous Materials Information System (WHMIS).

What is the Government of Canada doing?

  • The Final Screening Assessment for M4Q was published on March 28, 2015.
  • Based on the conclusion of the final screening assessment, the Government of Canada proposes that no further action be taken on M4Q.

What can Canadians do?

  • 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 may be exposed to M4Q in the workplace should consult with their employer and occupational health and safety representative about safe handling practices, applicable laws and requirements under the Workplace Hazardous Materials Information System (WHMIS).
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