Tributyltins (TBTs) are part of a group of substances called organotins, which are mainly used in the processing of PVC (a type of plastic) and as pesticides. TBTs for non-pesticidal uses are no longer manufactured or used in Canada as a primary material, but may be present in other organotin products (mono- and dibutyltins containing less than 1% of TBTs and tetrabutyltin containing up to 30% of TBTs).
The Follow-up to the 1993 Ecological Risk Assessment of Organotin Substances on Canada’s Domestic Substances List was published by Environment Canada in the Canada Gazette, Part I on August 8, 2009, under section 68 of the Canadian Environmental Protection Act, 1999 (CEPA 1999). This assessment report concluded that non-pesticidal TBTs are entering, or may enter, 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, as defined in paragraph 64(a) of CEPA 1999.
Based on the conclusions of the assessment, it was therefore recommended that non-pesticidal TBTs be added to Schedule 1 of CEPA 1999. Additionally, tributyltins meet the criteria for persistence and bioaccumulation potential as set out in the Persistence and Bioaccumulation Regulations.
In addition, Health Canada conducted in 2003 an assessment of the human health effects of non-pesticidal organotins and concluded that non-pesticidal organotins, including tributyltins, do not meet the criteria set out under paragraph 64(c) of CEPA 1999.
TBTs were added to the Prohibition of Certain Toxic Substances Regulations, 2012. Furthermore the following initiatives are in place or are being developed to manage any potential release of substances where TBTs may be present:
- An Environmental Performance Agreement Respecting the Use of Tin Stabilizers in the Vinyl Industry has been in place since March 10, 2008, to manage the release of tin stabilizers (mono- and dibutyltins) into the environment, including any TBTs that may be present in the stabilizers.
- A Code of Practice is currently being developed under section 54 of CEPA 1999 to manage releases of tetrabutyltin to the aquatic environment, including any potential release of TBTs that may be present in tetrabutyltin. This would apply to all facilities involved with tetrabutyltin in Canada.
- With respect to pesticidal uses of TBTs, the use of TBTs in anti-fouling paints (which are used to coat the bottoms of ships to prevent sea life from attaching themselves to the hull) on ship hulls has been prohibited in Canada since 2002, following the special review by Health Canada's Pest Management Regulatory Agency. In addition, a proposed re-evaluation decision for tetrabutyltin compounds was published on July 15, 2010, which proposed a phase-out of the remaining pesticidal uses of TBT compounds as a material preservative, under the Pest Control Products Act. A final regulatory decision is pending consideration of comments received during the consultation process.
For more information on organotin substances, please visit the Chemical Substances Website.
- Follow-up to the 1993 Ecological Risk Assessment of Organotin Substances on Canada's Domestic Substances List (August 2009)
- Follow-up Report on Non-Pesticidal Organotin Compounds for Which Data Were Insufficient to Conclude Whether the Substance Was “Toxic” to Human Health (May 2003)
- CEPA 1999 Schedule 1 - List of Toxic Substances – TBTs were added to the List of Toxic Substances (June 2011)
Risk Management Strategy
Click on the following link to view strategies and actions recommended to manage risks associated with the substance:
Risk Management Tool(s)
Tool(s) developed to manage risks associated with the substance:
- Prohibition of Certain Toxic Substances Regulations, 2012 (January 2013)
- Environmental Performance Agreement Respecting the Use of Tin Stabilizers in the Vinyl Industry (March 2008)
- Code of Practice for the Management of Tetrabutyltin in Canada (November 2011)
Risk Management Supporting Activities
Activities supporting the development or implementation of the risk management tool(s):
Forms related to the Prohibition of Certain Toxic Substances Regulations, 2012:
- Schedule 3: Information Related to the Use of Certain Toxic Substances in a Laboratory for Analysis, in Scientific Research or as a Laboratory Analytical Standard
- Schedule 4: Information Required in an Application for a Permit or an Application for Renewal of a Permit
Consultation (past and present) on the substance:
- Responses to public comments received on the Prohibition of Certain Toxic Substances Regulations, 2012. (January 2013)
- Response to Comments Received on the Risk Management Approach for Non-Pesticidal Organotin Compounds and the Consultation Document for Tributyltins (July 2011)
- Consultation Document for the Proposed Risk Management Measures for the Non-Pesticidal Uses of Tributyltin (February 2011)
- Response to Comments Received for the Draft Follow-up to the 1993 Ecological Risk Assessment of Organotin Substances (July 2007)
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