Siloxane D5 (Cyclopentasiloxane, decamethyl-)

CAS Registry Number 541-02-6

What is it?

  • D5, also known as cyclopentasiloxane, decamethyl-, is an industrial chemical.

How is it used?

  • D5 is found or used in the manufacture of a wide variety of products.
  • The predominant use of D5 worldwide and in Canada is in blending and formulating consumer products. D5 is also used in manufacturing silicone polymers. D5 is used in personal care products such as hair/skin care products, antiperspirants and deodorants.
  • Silicone polymers that may contain residual amounts of D5 (from the manufacturing process) are used in biomedical applications and have also been approved as active and non-active ingredients in pharmaceuticals in Canada.
  • Silicone polymers are also used in industrial processes (for example, as surfactants in certain pesticide products and as defoamers), in lubricants, cleaning products, sealants, adhesives, waxes, polishes and coatings. An increasing number of commercial dry cleaners in Canada use D5 as a dry-cleaning fluid.
  • D5 is not currently manufactured in Canada; however, it is imported into Canada.

Why did the Government of Canada assess it?

  • Prior to assessment, D5 was identified as a potential concern to the environment based on available information regarding possible persistence, accumulation and potential to cause harm to the environment.
  • D5 was not considered to be a high priority for assessment of potential risks to human health; however, potential health effects were also evaluated in the screening assessment.

How is it released to the environment?

  • Because D5 is used to make many different products, it may be released to the environment from many different sources.

What is the Government of Canada doing?

  • The Government of Canada has conducted an evaluation of D5 based on science, called a screening assessment. In 2009, the assessment determined that D5 is not considered to be harmful to human health but is harmful to the environment. The final screening assessment report and proposed risk management approach document on D5 were published on January 31, 2009.
  • Following the publication of the final screening assessment report, a Notice of Objection requesting the establishment of a Board of Review was filed by the Silicones Environmental, Health and Safety Council of North America in July 2009. The Council submitted information regarding the toxicity of D5. The Minister of the Environment considered the information submitted and, on August 21, 2010, established a Siloxane D5 Board of Review to inquire into the nature and extent of the danger posed by D5 to the Canadian environment or its biological diversity.
  • On October 20, 2011, after consideration of the intrinsic properties of D5 and all of the available scientific information, the Board completed its Report of the Board of Review for Siloxane D5 and recommended that D5 does not pose a danger to the environment.
  • On February 25, 2012, after consideration of all available information including the Board's report and recommendations, the Government of Canada has published a revised decision on D5.
  • The Government of Canada is therefore concluding that D5 is not entering the environment in a quantity or under conditions that constitute a danger to the environment.

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 the chemical to which you are exposed). D5 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 D5 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.
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