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Report of the Board of Review for Decamethylcyclopentasiloxane (Siloxane D5)

3 Statement of Reasons of the Siloxane D5 Board of Review


3.1 Introduction and Background

41. On August 21, 2010, the Minister of the Environment (“Minister”) published a Ministerial Notice (“Notice”)3 in the Canada Gazette in which he established a board of review pursuant to subsection 333(1) of the Canadian Environmental Protection Act, 19994 (“CEPA 1999”) to inquire into the nature and extent of the danger posed by decamethylcyclopentasiloxane (“Siloxane D5”).

42. The Minister’s decision followed a final screening assessment (“Screening Assessment”) of Siloxane D5 (Environment Canada and Health Canada 2008 ("EC" and "HC" 2008))5 conducted by Health Canada and Environment Canada (sometimes referred to as the “Department” or “Departments”) pursuant to section 74 of CEPA 1999. The Screening Assessment was published on January 31, 2009 and concluded that, based on the available information, Siloxane D5 was entering the environment in a quantity or concentration or under conditions that may have an immediate or long-term harmful effect on the environment or its biological diversity6 and, as a consequence, met one or more of the criteria set out in section 74 of CEPA 1999.

43. As a result of that determination, the Minister of Health and the Minister of the Environment recommended that Siloxane D5 be added to the Toxic Substances List in Schedule 1 of CEPA 1999. This decision was based on the potential for harm in the environment; concerns for humans were not identified.

44. One of the affected industry stakeholders, the Silicones Environmental, Health and Safety Council of North America (“SEHSC”), filed a Notice of Objection on July 10, 2009 pursuant to subsection 332(2) of CEPA 1999. The SEHSC requested that a board of review be established to inquire into the nature and extent of the danger posed by octamethylcyclotetrasiloxane (“Siloxane D4”) and Siloxane D5.

45. The SEHSC claimed that the Screening Assessments for these substances were not conducted in a manner that was consistent with the best available science and that errors were made in the approach used by government officials when assessing them. Furthermore, the SEHSC stated that new scientific information was available to demonstrate that Siloxanes D4 and D5 did not meet the criteria for toxicity and that new risk assessments should be undertaken.

46. Taking into account that new scientific information with respect to Siloxane D5 had been made available since the Screening Assessment was published in 2008, the Minister of the Environment decided to establish a board of review (the “Board”) pursuant to subsection 333(1) of CEPA 1999. However, the request with respect to Siloxane D4 was denied.

47. The Minister appointed Professor John Giesy, Ph.D., FRSC as Chair, and Professor Keith Solomon, Ph.D., Fellow of the Academy of Toxicological Sciences (“ATS”), and Professor Sam Kacew, Ph.D., Fellow ATS, as members of the Board. The Minister directed the Board to prepare and submit a report, together with recommendations, and the evidence that was presented, on or before March 31, 2011 (see Appendix A).

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3.2 Procedural Steps in the Board of Review Process

48. After the Notice was published, the Board sent notice of this proceeding to a wide range of potentially interested stakeholders and informed them that they could request intervenor status, as permitted by section 10 of the Rules of Procedure for Boards of Review (“Rules”)7. The notice from the Board was sent to all stakeholders who had indicated an interest and/or participated in the Screening Assessment conducted by the Departments. The notice was also sent to several daily newspapers for publication as a public service announcement and it was posted on the Board’s website.

49. The Board received two requests for intervenor status, one from the Canadian Cosmetic, Toiletry and Fragrance Association (“CCTFA”), and the other from a coalition consisting of the Canadian Environmental Law Association, the International Institute of Concern for Public Health, Chemical Sensitivities Manitoba, and the Crooked Creek Conservancy Society of Athabasca (the “Coalition”). In considering those requests and the contribution they could make to these proceedings, the Board granted intervenor status to both requestors.

50. The Coalition requested and received permission to provide written submissions. The Coalition indicated that it would not participate in the hearing unless funding for that purpose was provided. In responding to the funding request, the Board noted that, pursuant to article 4 of the Terms of Reference contained in the Notice, no funding would be provided to any person or party. Consequently, the Coalition participated by providing written submissions in this proceeding.

51. The CCTFA requested and received permission to participate fully by providing written submissions and participating in the hearing. Consequently, the CCTFA participated in all steps leading up to the hearing. However, before the hearing began in April 2011, the CCTFA informed the Board that it would be represented by counsel for the SEHSC during the hearing.

52. As a preliminary matter, and because it was aware that new scientific information relating to Siloxane D5 was, or would be available, the Board requested that parties provide a timeframe for the production of any new scientific information that would be pertinent to the assessment. The parties, with the exception of the Coalition, indicated that scientific information that was not available at the time the Screening Assessment was conducted would be available by the end of 2010.

53. Consequently, to ensure that the Board considered the latest scientific information relating to Siloxane D5, the Board determined that it would not be possible to complete its investigation and deliberations within the timeframe provided in the Notice. As a result, the Board communicated with the Minister on November 12, 2010 advising him that the Board would be in a position to issue its report by September 30, 2011 (a copy of this letter can be found in Appendix B below). The Minister subsequently requested that the Board issue its report in both English and French, and extended the Board's delivery date to October 31, 2011 (see Appendix C below).

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3.3 Determination of Scope of the Board’s Mandate

54. As the Board undertook its review, an issue arose with respect to the scope of its mandate. In particular, it was suggested that the Board consider the nature and extent of the danger posed by Siloxane D5 to human health in addition to considerations related to the environment. After considering the available information, the Board was of the opinion that this issue warranted further consideration and asked the parties for their views.

55. After considering the submissions received from the parties, on November 16, 2010, the Board issued a ruling in which it stated that its mandate was to focus on the nature and extent of the danger posed by Siloxane D5 to the environment (a complete copy of this ruling can be found in Appendix D). The Board stated in part:

12. Taking into account the background leading up to the establishment of the Board, and the views of parties, the Board has concluded that the scope of its review should focus on the nature and extent of the danger posed by siloxane D5 to the environment or its biological diversity.

13. The Board was established following the Minister’s consideration of the Notice of Objection filed by the Silicones Council. The Notice of Objection indicated that new data and information related to the effects of siloxane D5 on the environment or its biological diversity were available to cast into doubt the conclusion reached by the government in the screening assessments.

14. While the Board recognises the potentially broad scope of its mandate, at this point, it does not believe that issues related to human health should be the subject of this review. In reaching this decision, the Board took note of the preamble referred to above in the Notice dated August 21, 2010 where it stated that, according to the screening assessment, siloxane D5 is entering the environment in a quantity or concentration or under conditions that have or may have an immediate or long-term harmful effect on the environment or its biological diversity. There is no mention in the Notice to issues related to human health.

15. The Board also notes that even though the CEPA 1999 provides that a board of review may be established by the Minister of the Environment alone or in conjunction with the Minister of Health, the Notice states that the Minister of the Environment alone has established this Board.

16. Further, the Board has been advised by parties that the new data and information available following the issuance of the government's screening assessment relates only to environmental or biological diversity issues.

17. In coming to this decision, the Board has carefully considered the points that the Coalition raised in its submission where it proposed a broader scope of review. No doubt, some of the points they raise will be discussed during this process, including the precautionary principle. But other points, including the cumulative impact of siloxanes D4, D5 and D6 on human health, and their impact on vulnerable populations, as well as the human health issues they urge the Board to consider are not supported by new information and, in the Board’s view, are beyond the mandate of this Board in this review.

18. While the Board will focus on issues related to the environment or its biodiversity, it reserves the discretion to revisit the scope of its inquiry following its review of the post-screening assessment data and information. Should these data and information indicate that matters related to human health should also be considered, the Board will inform the parties and provide them with an opportunity to address these issues.

56. Consequently, the Board was alerted to the possibility that scientific information relating to human health might be presented during this proceeding. However, following a review of the scientific information available, it became clear to the Board that human health issues were not engaged and the Board’s focus was therefore limited to considering the nature and extent of the danger posed by Siloxane D5 to the environment.

57. In the steps leading up to the hearing, the parties, with the exception of the Coalition, provided new scientific information and analysis. All of that information, in addition to the information taken into account by government officials during the Screening Assessment, was filed with the Board and made available to the parties.

58. In addition, written submissions were received from all parties. Parties were also given the opportunity to pose interrogatory questions to opposing parties. Answers to those interrogatories were provided in writing and were, similarly, made available to all parties.

59. As a result, before the hearing began, parties and the Board had a comprehensive and extensive record relating to Siloxane D5. In the Board’s view, the range and quality of data presented was sufficient for it to conduct a meaningful inquiry into the nature and extent of the danger to the environment posed by Siloxane D5.

60. Hearings were conducted from April 26 to May 6, 2011, and final arguments were heard on May 26, 2011. Testimony was received from witnesses called by Environment Canada and the SEHSC/CCTFA, all of whom were qualified as experts in various scientific disciplines. Additionally, the Board called one witness, Dr. Steve Dungey, from the United Kingdom Environment Agency.

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3.4 Relevant Legislation and Regulations

61. CEPA 1999 establishes the legislative framework within which chemical substances are assessed in order to determine whether they cause or may cause harmful effects to humans or the environment. In conducting an assessment of the potential harm posed by Siloxane D5, the Board’s attention was drawn to the following provisions:

Paragraph 2(1)(a):

In the administration of this Act, the government of Canada shall, having regard to the constitutional laws in Canada and subject to subsection 1.1,

  1. exercise its powers in a manner that protects the environment and human health, applies the precautionary principle that, where there are threats of serious or irreversible damage, lack of full scientific certainty shall not be used as a reason for postponing cost-effective measures to prevent environmental degradation, and promotes and reinforces enforceable pollution prevention approaches.

Subsection 3(1):

“biological diversity” means the variability among living organisms from all sources, including, without limiting the generality of the foregoing, terrestrial and marine and other aquatic ecosystems and the ecological complexes of which they form a part and includes the diversity within and between species and of ecosystems

“environment” means the components of the Earth and includes

  1. air, land and water,
  2. all layers of the atmosphere;
  3. all organic and inorganic matter and living organisms; and
  4. the interacting natural systems that include components referred to in paragraphs (a) and (c)

Section 64:

For the purposes of this Part and Part 6, except where the expression “inherently toxic” appears, a substance is toxic if it is entering or may enter the environment in a quantity or concentration or under conditions that

  1. have or may have an immediate or long-term harmful effect on the environment or its biological diversity;
  2. constitute or may constitute a danger to the environment on which life depends; or
  3. constitute or may constitute a danger in Canada to human life or health

Section 68:

For the purpose of assessing whether a substance is toxic or is capable of becoming toxic, or for the purpose of assessing whether to control, or the manner in which to control, a substance, including a substance specified on the List of Toxic Substances in Schedule 1, either Minister may

  1. collect or generate data and conduct investigations respecting any matter in relation to a substance, including, without limiting the generality of the foregoing,
    1. whether short-term exposure to the substance causes significant effects,
    2. the potential or organisms in the environment to be widely exposed to the substance,
    3. whether organisms are exposed to the substance via multiple pathways,
    4. the ability of the substance to cause a reduction in metabolic functions of an organism,
    5. the ability of the substance to cause delayed or latent effects over the lifetime of an organism,
    6. the ability of the substance to cause reproductive or survival impairment of an organism,
    7. whether exposure to the substance has the potential to contribute to population failure of a species,
    8. the ability of the substance to cause transgenerational effects;
    9. quantities, uses and disposal of the substance,
    10. the manner in which the substance is released into the environment,
    11. the extent to which the substance can be dispersed and will persist in the environment,
    12. the development and use of alternatives to the substance,
    13. methods of controlling the presence of the substance in the environment, and
    14. methods of reducing the quantity of the substance used or produced or the quantities or concentration of the substance released into the environment;
  2. correlate and evaluate any data collected or generated under paragraph (a) and publish results of any investigations carried out under that paragraph; and
  3. provide information and make recommendations respecting any matter in relation to a substance, including, without limiting the generality of the foregoing, measures to control the presence of the substance in the environment.

Section 90.(1):

Subject to subsection (3), the Governor in Council may, if satisfied that a substance is toxic, on the recommendation of the Ministers, make an order adding the substance to the List of Toxic Substances in Schedule 1.

Section 332.(1):

The Minister shall publish in the Canada Gazette a copy of every order or regulation proposed to be made by the Minister or the Governor in Council under this Act, except a list, or an amendment to a list, referred to in section 66, 87, 105, or 112 or an interim order made under section 94, 163, 173, 183, or 200.1.

(2) Within 60 days after the publication of a proposed order or regulation in the Canada Gazette under subsection (1) or a proposed instrument respecting preventive or control actions in relation to a substance that is required by section 91 to be published in the Canada Gazette, any person may file with the Minister comments with respect to the order, regulation or instrument or a notice of objection requesting that a board of review be established under section 333 and stating the reasons for the objection.

(3) No order, regulation or instrument need be published more than once under subsection (1), whether or not it is altered after publication.

Section 333.(1):

Where a person files a notice of objection under subsection 77(8) or 332(2) in respect of

  1. a decision or a proposed order, regulation or instrument made by the Governor in Council, or
  2. a decision or a proposed order or instrument made by either or both Ministers,

the Minister or the Ministers may establish a board of review to inquire into the nature and extent of the danger posed by the substance in respect of which the decision is made or the order, regulation or instrument is proposed.

(2) Where a person files a notice of objection under subsection 9(3) or 10(5) in respect of an agreement or a term or condition of the agreement, the Minister may establish a board of review to inquire into the matter.

(3) Where a person or government files with the Minister a notice of objection under subsection 332(2) with respect to regulations proposed to be made under section 167 or 177 within the time specified in that subsection, the Minister shall establish a board of review to inquire into the nature and extent of the danger posed by the release into the air or water of the substance in respect of which the regulations are proposed.

(4) Where a person files with the Minister a notice of objection under subsection 332(2) with respect to regulations proposed to be made under Part 9 or section 118 within the time specified in that subsection, the Minister shall establish a board of review to inquire into the matter raised by the notice.

(5) Where a person files with the Minister a notice of objection under section 134 within the time specified in that section, the Minister may establish a board of review to inquire into the matter raised by the notice.

(6) Where a person files with the Minister a notice of objection under section 78 in respect of the failure to make a determination about whether a substance is toxic, the Minister shall establish a board of review to inquire into whether the substance is toxic or capable of becoming toxic.

Section 334.(1):

A board of review shall consist of not fewer than three members.

(2) A person is not eligible to be appointed as a member of a board of review unless the person is knowledgeable about the Canadian environment, environmental and human health or traditional aboriginal ecological knowledge.

Section 335:

A board of review shall give any person or government a reasonable opportunity, consistent with the rules of procedural fairness and natural justice, of appearing before it, presenting evidence and making representations.

62. In respect of the relevant regulatory framework, reference was made to the Persistence and Bioaccumulation Regulations (“Regulations”)8 and, in particular, sections 3 through 5 which read as follows:

3. A substance is persistent when it has at least one of the following characteristics:

  1. in air,
    1. its half-life is equal to or greater than 2 days, or
    2. it is subject to atmospheric transport from its source to a remote area;
  2. in water, its half-life is equal to or greater than 182 days;
  3. in sediments, its half-life is equal to or greater than 365 days;

    or

  4. in soil, its half-life is equal to or greater than 182 days.

4. A substance is bioaccumulative

  1. when its bioaccumulation factor is equal to or greater than 5,000;
  2. if its bioaccumulation factor cannot be determined in accordance with a method referred to in section 5, when its bioconcentration factor is equal to or greater than 5,000; and
  3. if neither its bioaccumulation factor nor its bioconcentration factor can be determined in accordance with a method referred to in section 5, when the logarithm of its octanol-water partition coefficient is equal to or greater than 5.

5. The determination of persistence and bioaccumulation with respect to a substance under sections 3 and 4 must be made in accordance with generally recognised methods of the Organisation for Economic Co-operation and Development (OECD) or of some other similar organisation or, if no such methods exist, in accordance with generally recognized methods within the scientific community and taking into account the intrinsic properties of the substance, the ecosystem under consideration and the conditions in the environment.

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3.5 Framing the Board’s Mandate

63. Before turning to its analysis of the science, the Board first considered what should be the body of scientific information to inform this review and on what issues this review should be focussed.

3.5.1 Positions of the Parties

64. During the hearings, counsel for both Environment Canada and the SEHSC/CCTFA agreed that the Board was to conduct a de novo assessment of the available science in determining the nature and extent of the danger posed by Siloxane D5 to the environment. However, the positions of both parties diverged on the path that the Board should follow in conducting its review.

65. Environment Canada stated that it was not necessary for the Board to review the Screening Assessment conducted by government officials in 2008, nor would it be appropriate for the Board to pronounce on the conclusions arrived at in that assessment. The Board’s review, in other words, was not an appeal per se of the Screening Assessment.

66. Furthermore, Environment Canada took the position that the Board was not bound by the provisions in either CEPA 1999 or the Regulations. Accordingly, the Board should not make a determination about whether Siloxane D5 is “CEPA-toxic” in accordance with section 64 of CEPA 1999. Likewise, the Board should not make a determination or recommendation that Siloxane D5 should, or should not, be added to Schedule 1 of CEPA 1999 as a toxic substance. Those matters are the prerogative of the Minister of the Environment.

67. Additionally, according to Environment Canada, the Board must not take into account factors such as socio-economic considerations or assess the value this substance might have for commercial purposes. The Board’s mandate was limited to conducting a scientific review of the nature and extent of the danger to the environment posed by Siloxane D5.

68. Finally, Environment Canada claimed that it was not necessary for the Board to determine whether harm was definitely being caused to the environment by Siloxane D5. Further, because CEPA 1999 is founded on the principles of protection and precaution, as outlined in section 2, the Board’s analysis should not be based on the “average or standard use” of Siloxane D5 for commercial purposes or its uses. As counsel for Environment Canada stated, the Board’s review should not be based on the “average or standard use of the chemical in products in Canada. As a result, for example, if the pure product poses a danger, that must form part of the Board’s assessment” (Transcript of the Public Hearings, Vol. 9, p. 1129).

69. Counsel for Environment Canada went on to state, however, that the question of danger is “… not strictly restricted to what is currently happening. It is whether there is a danger and the danger, obviously from the ordinary meaning of that term, can mean a future potential danger. The question then becomes, what is the probability of that potential?” (Transcript of the Public Hearings, Vol. 9, p. 1117).

70. The SEHSC/CCTFA submitted that although the Board must conduct a de novo assessment of the science, it also needed to review the Screening Assessment conducted by Environment Canada and Health Canada and the manner in which the Screening Assessment was conducted. In view of the conclusion reached in the Screening Assessment, the SEHSC/CCTFA stated that the Board must have particular regard to paragraph 64(a) of CEPA 1999, which states:

Section 64:

For the purposes of this Part and Part 6, except where the expression “inherently toxic” appears, a substance is toxic if it is entering or may enter in a quantity or concentration or under conditions that

  1. have or may have an immediate or long-term harmful effect on the environment or its biological diversity.

71. The SEHSC/CCTFA also urged the Board to give careful consideration to section 5 of the Regulations and determine whether the available science demonstrated that Siloxane D5 met the criteria for bioaccumulation and persistence, taking into account the “intrinsic properties” of the substance (Transcript of the Public Hearings, Vol. 9, p. 1200).

72. The SEHSC/CCTFA urged the Board to take into account “real-world” quantities or concentrations and conditions under which Siloxane D5 is used. That is to say, the assessment of the substance should be rooted in the data and information which details how and where the substance is used, the quantities used, the concentration of the substance, and the effects it currently has or might have on the environment. The Board was not, in its view, conducting a hypothetical assessment based on worst-case scenarios, where the available data or circumstances did not warrant that manner of proceeding.

73. The Board agreed with both parties that its mandate was to conduct an independent, de novo scientific assessment of the relevant and available science relating to Siloxane D5.

74. The Board also agreed with counsel from Environment Canada that its mandate was not to conduct this review in the manner of an appeal of the Screening Assessment. However, it was also the opinion of the Board that it could not, and should not ignore the analysis and conclusions expressed in the Screening Assessment as they provide the context and foundation upon which this review was based.

75. With respect to the review process for Siloxane D5, the Board agreed with Environment Canada that its mandate was not to pronounce on whether Siloxane D5 is “CEPA-toxic” according to section 64, nor was it the Board’s mandate to determine whether the substance should, in accordance with section 90 of CEPA 1999, be added to Schedule 1 as a toxic substance. Those are matters that are entirely within the purview of the Minister of the Environment.

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3.5.1.1 The Meaning of “Danger” to the Environment

76. In conducting its de novo scientific assessment of the nature and extent of the danger posed by Siloxane D5 to the environment, the Board considered how the term “danger” should be interpreted. The term “danger” is not defined in CEPA 1999 or in the Regulations. It therefore fell to the Board to interpret the meaning of that term in the context of the Notice issued by the Minister of the Environment.

77. The Board noted that the term “danger” is found in paragraphs 64(b) and (c) of CEPA 1999. Those paragraphs contrast slightly with paragraph 64(a) which refers to “harmful effect”. Section 64 reads:

For the purposes of this Part and Part 6, except where the expression “inherently toxic” appears, a substance is toxic if it is entering or may enter the environment in a quantity or concentration or under conditions that

  1. have or may have an immediate or long-term harmful effect on the environment or its biological diversity;
  2. constitute or may constitute a danger to the environment on which life depends; or
  3. constitute or may constitute a danger in Canada to human life or health

[emphasis added]

78. Referring back to the Screening Assessment issued by Environment Canada and Health Canada, it concluded, in part, that:

Based on the information presented in this screening assessment on the potential of D5 to cause ecological harm, it is concluded that decamethylcyclopentasiloxane is entering or may be entering the environment in a quantity or concentration or under conditions that have or may have an immediate or long-term harmful effect on the environment or its biological diversity (EC & HC 2008).

[emphasis added]

79. Although that conclusion parallels the toxicity threshold in paragraph 64(a) of CEPA 1999 (i.e., “harmful effect”), in the Notice issued by the Minister, he chose to craft the mandate in terms of the “danger”, the term found in paragraphs 64(b) and (c). In attempting to give meaning to the term “danger”, the Board considered whether to interpret it to mean something different from the term “harmful effect”.

80. In analysing this issue, the Board was able to draw on guidance offered by the Supreme Court of Canada in R. v. Hydro-Québec, [1977] 3 S.C.R. 213. Although that case revolved around the constitutionality of some provisions of the Canadian Environmental Protection Act, R.S.C. 1985 (“1985 Act”), the Court had an opportunity to comment on section 11, dealing with the thresholds for determining whether a substance was toxic. Section 11 of the 1985 Act stated:

11. For the purposes of this Part, a substance is toxic if it is entering or may enter the environment in a quantity or concentration or under conditions

  1. having or that may have an immediate or long-term harmful effect on the environment;
  2. constituting or that may constitute a danger to the environment on which human life depends: or
  3. constituting or that may constitute a danger in Canada to human life or health.

[emphasis added]

81. It is readily apparent that section 11 is largely mirrored in section 64 of CEPA 1999. Just as in CEPA 1999, the 1985 Act establishes two toxicity thresholds: “harmful effect” and “danger”.

82. At paragraph 31, the minority of the Court noted that there was no definition of the terms “danger” or “harmful effect” in section 11. Nevertheless, in looking at section 11, the Court reframed the essence of that section by stating that toxicity would be shown:

If a substance…poses or may pose a risk to human life or health, or to the environment upon which human health depends, or to any aspect of the environment itself…

[emphasis added]

83. After considering that section and its different components holistically, the minority stated that the threshold for toxicity was based on the “risk” posed by the substance to human health or the environment. In other words, it drew no meaningful distinction between the terms “danger” and “harmful effect”.

84. At paragraph 141 of that decision, the majority of the Court noted that, for a substance to be found to be toxic according to section 11, it must be demonstrated that the substance is:

…entering or may enter the environment in a quantity or concentration or under conditions that result in the detrimental effects on the environment, human life and human health described in [11] paragraphs (a) to (c).

[emphasis added]

85. The majority of the Court similarly chose not to draw any significant distinction between the toxicity thresholds of “danger” and “harmful effects” in paragraphs (a)-(c) of section 11, choosing instead to reformulate the toxicity threshold as “detrimental effects”.

86. Furthermore, the majority also opined that an assessment of the toxicity of a substance should take into account the manner and quantities in which the substance is found in the environment and the effects it has or might have on the environment, human life, and human health.

87. The Board recognised that it was not mandated to determine if Siloxane D5 met the toxicity thresholds provided for in paragraphs 64(a)-(c) of CEPA 1999. But, the Supreme Court of Canada’s interpretation of the meaning of section 11 of the 1985 Act did assist the Board in determining how it should approach the interpretation of the term “danger”, as provided in the Notice.

88. Taking the guidance from that case into account, the Board interpreted its mandate to mean that it was to inquire into the nature and extent of the risk posed, if any, by Siloxane D5 to the environment and to determine whether detrimental effects were caused, or might be caused. In other words, the Board was mandated to conduct what was, in essence, a de novo risk assessment of the substance taking into account all of the available, relevant, scientific information about Siloxane D5.

89. When conducting the de novo risk assessment, the Board concluded that best scientific practice required that it take into account information about the “intrinsic” physical and chemical properties of the substance along with its uses, releases, dissipation, transformation, and degradation, pathways of exposures, toxicity, and effects. Additionally, the Board determined that the review should be rooted in real-world terms. That is to say, the Board decided to conduct its review taking into account the quantities or concentrations and conditions under which Siloxane D5 is used or, based on the best information available, the likely future volumes or uses. This approach permitted the Board to consider not only current patterns and methods of use, but also assess the potential changes in use and concentrations, in order to analyse the nature and extent of the risk (or danger) posed by Siloxane D5 to the environment.

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3.5.1.2 Persistence and Bioaccumulation Regulations

90. Before considering the scientific information related to Siloxane D5, the Board determined that another aspect of the regulatory regime needed to be addressed. During the course of these proceedings, there was considerable discussion about, and reference to, the Regulations, in particular sections 3 to 5. For ease of reference, those sections are reproduced here:

3. A substance is persistent when it has at least one of the following characteristics:

  1. in air,
    1. its half-life is equal to or greater than 2 days, or
    2. it is subject to atmospheric transport from its source to a remote area;
  2. in water, its half-life is equal to or greater than 182 days;
  3. in sediments, its half-life is equal to or greater than 365 days; or
  4. in soil, its half-life is equal to or greater than 182 days.

4. A substance is bioaccumulative

  1. when its bioaccumulation factor is equal to or greater than 5,000;
  2. if its bioaccumulation factor cannot be determined in accordance with a method referred to in section 5, when its bioconcentration factor is equal to or greater than 5,000; and
  3. if neither its bioaccumulation factor nor its bioconcentration factor can be determined in accordance with a method referred to in section 5, when the logarithm of its octanol-water partition coefficient is equal to or greater than 5.

5. The determination of persistence and bioaccumulation with respect to a substance under sections 3 and 4 must be made in accordance with generally recognised methods of the Organisation for Economic Co-operation and Development (OECD) or of some other similar organisation or, if no such methods exist, in accordance with generally recognized methods within the scientific community and taking into account the intrinsic properties of the substance, the ecosystem under consideration, and the conditions in the environment.

91. Environment Canada and the Coalition took the position that Siloxane D5 met, and continues to meet, the thresholds given in sections 3 and 4 of the Regulations. Keeping in mind the overarching objective in CEPA 1999 to protect the environment, Environment Canada and the Coalition argued that, those thresholds having been met, Siloxane D5 poses or may pose a danger to the environment. Later in this report, the Board comments on the persistence and accumulation characteristics of Siloxane D5 in relation to the regulatory thresholds referred to above.

92. The SEHSC/CCTFA, on the other hand, claimed that the regulatory thresholds in sections 3 and 4 of the Regulations were not met in the case of Siloxane D5. They stated that, based on a proper analysis of the scientific information now available, those thresholds have not been met or exceeded.

93. However, the SEHSC/CCTFA went on to further state that: i) any analysis of persistence and bioaccumulation of Siloxane D5 must take into account its intrinsic properties as provided for in section 5 of the Regulations and, ii) irrespective of whether thresholds in sections 3 and 4 have been met, it is necessary to further consider the intrinsic properties of Siloxane D5 to properly assess whether it poses a danger. When the intrinsic properties of Siloxane D5 are taken into account, the SEHSC/CCTFA claims that it does not pose a danger to the environment.

94. Section 5 of the Regulations is somewhat unclear about whether the intrinsic properties of a chemical should always be considered when assessing persistence and bioaccumulation. That section might be interpreted to mean that the intrinsic properties of a substance should only be taken into account in cases where it is not possible to rely on the generally recognised methods of the OECD or other similar organisation when assessing persistence and bioaccumulation. The Board does not, however, agree with such an interpretation.

95. The Board determined that section 5 of the Regulations could and should be read to require that, when assessing persistence and bioaccumulation, evaluators should take into account the other factors referred to in section 5: the intrinsic properties of a chemical, the ecosystem under consideration, and conditions in the environment. Furthermore, the Board interpreted the term “intrinsic properties” to mean intensive properties such as vapour pressure and solubility as well as extensive properties such as toxicity.

96. An analysis of persistence and bioaccumulation performed in accordance with generally recognised methods within the scientific community can only be adequately conducted if the particular characteristics of a chemical under review, and its impact on the ecosystem or environment, are adequately considered. It would not be scientifically credible to ignore consideration of a substance’s intrinsic properties where that information is available.

97. Moreover, it is important to consider how the chemical is used and how it enters into the environment. Failure to take all available scientific information about a chemical into account could lead to a flawed conclusion about its danger to the environment.

98. The Board’s interpretation of section 5 appears to be consistent with the views of Environment Canada. In the State of the Science Report (EC 2011a, p. 18), when discussing the Regulations, Environment Canada stated:

The Regulations go on to indicate that “[t]he determination of persistence and bioaccumulation…must be made…taking into account the intrinsic properties of the substance, the ecosystem under consideration and the conditions in the environment.” Thus, determining whether these criteria are met involves professional judgement which considers the intrinsic properties of the substance and ecosystem under consideration.

[emphasis added]

99. As is discussed in detail later in this report, it is the Board’s opinion that Siloxane D5 is one of those chemicals whose intrinsic properties play a significant role in determining whether it is persistent and bioaccumulative and whether it poses a danger to the environment.

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3.5.1.3 The Role of Precaution in This Review

100. Finally, in conducting its review, the Board was reminded by all parties of the importance and role of the precautionary principle provided for in paragraph 2(1)(a) of CEPA 1999. The Board does understand the importance of, and need for, precaution when assessing the impact a chemical could have on human health or the environment.

101. It is also important though, to understand the proper application of the precautionary principle and the precautionary approach to risk assessment. When conducting a risk assessment, evaluators appropriately rely on the precautionary approach to the extent warranted. Consequently, where data gaps exist, or in cases where the data are equivocal or unreliable, evaluators rightfully rely on a conservative or precautionary approach, using reasonable worst-case assumptions and uncertainty factors, when analysing information or modelling. This approach ensures an appropriate degree of caution and protection.

102. The precautionary principle comes into play when governments are determining what measures, if any, they should impose when a chemical of concern has been identified following a risk assessment. The degree to which the precautionary principle affects the government’s approach to the management of a chemical will in part depend on the quality and scientific robustness of the available information, and the nature and extent of the risk revealed by that information.

103. In this case, there is sufficient credible and trustworthy scientific information about Siloxane D5 for the Board to conduct a scientifically-robust and meaningful risk assessment. In these circumstances, because it had credible and trustworthy scientific information before it, the Board did not need to rely solely on the precautionary approach in the same way as required by those conducting the Screening Assessment.

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3 Canada Gazette, vol. 144, no. 34, August 21, 2010. See section 9.1 for a copy of the Notice.

4 S.C. 1999, c. 33.

5 Bracketed references identify the author and, where relevant, the page number.

6 Hereinafter, the term “environment” refers to the phrase “environment or its biological diversity”.

7 SOR/2003-28. The Rules of Procedure for Boards of Review were amended following the initiation of this review: see SOR/2011, January 11, 2011.

8 SOR/2000-107.

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