Toxic substances list: BNST
The Benzenamine, N-phenyl-, reaction products with styrene and 2,4,4-trimethylpentene (BNST) is an antioxidant used as an additive in vehicle engine oil and in some commercial and industrial lubricants. Available information suggests that there may also be a minor use of BNST as an additive in rubber applications for industrial equipment and machinery and in rubber parts used in vehicles. BNST is manufactured and imported in Canada.
On August 1, 2009, the Ministers of the Environment and of Health published, in Part I of the Canada Gazette, their final decision on the screening assessment of BNST. The screening assessment report concluded that BNST 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. Additionally, BNST meets the criteria for persistence and bioaccumulation as set out in the Persistence and Bioaccumulation Regulations. Based on the conclusions of the assessment, a Final Order adding BNST to the List of Toxic Substances in Schedule 1 under the Canadian Environmental Protection Act, 1999 (CEPA 1999) was published in Part II of the Canada Gazette on March 2, 2011.
The risk management approach for BNST, published on August 1, 2009, proposed the addition of BNST to the Prohibition of Certain Toxic Substances Regulations, 2005 to prohibit the manufacture, use, sale, offer for sale or import of the substance and products containing it.
The proposed Prohibition of Certain Toxic Substances Regulations, 2012 including controls on BNST were published in the Canada Gazette, Part I on July 23, 2011, for a 75-day comment period.
On January 2, 2013, the Prohibition of Certain Toxic Substances Regulations, 2012 (the prohibition regulations) were published in the Canada Gazette, Part II. These regulations repealed and replaced the Prohibition of Certain Toxic Substances Regulations, 2005.
On November 5, 2016, the proposed Regulations Amending the Prohibition of Certain Toxic Substances Regulations, 2012 were published in the Canada Gazette, Part I, for a 75-day public comment period and proposed to modify existing controls for BNST to provide flexibility to allow the use of BNST beyond March 2018, in replacement parts and legacy equipment.
On December 10, 2016, the Ministers of Environment and of Health published the draft screening assessment of substituted diphenylamines (SDPA), including BNST, and proposed to conclude that these substances do not meet any of the criteria set out under CEPA 1999, for listing a toxic substance. A consultation document was also published on December 10, 2016 for a 60-day comment period, describing the proposed approach respecting regulatory amendments for BNST, pending the outcome of the final decision of the Ministers.
On December 9, 2017, the Ministers published their final decision on the screening assessment of SDPA in the Canada Gazette, Part I. The assessment concluded that these substances, including BNST, do not meet any of the criteria set out under CEPA 1999, for listing as toxic substances. The Government of Canada proceeded to change the 2016 regulatory proposal and published the final Regulations Amending the Prohibition of Certain Toxic Substances Regulations, 2012 in Canada Gazette, Part II, on December 13, 2017, to remove existing prohibitions and controls on BNST. As a result, the substance BNST has been repealed from the scope of the prohibition regulations, along with all controls respecting that substance.
For more information on this substance, please visit the Chemical Substances website.
This substance is entering the environment from the following source(s):
Consultation (past and present) on the substance:
- Summary of Public Comments Received on the Government of Canada’s Draft Screening Assessment Reports and Risk Management Scope Document for BNST
- Proposed Risk Management Approach for BNST (Consultation Period closed)
- Consultation Document on risk management measure for BNST (Consultation Period closed)
- Environment Canada’s Response to Comments Received on the Consultation Document on the Risk Management Measure for BNST
- Response to comments on proposed Prohibition of Certain Toxic Substances Regulations, 2012
- Consultation document for amending prohibition of certain toxic substances: substituted diphenylamine substances (Consultation period closed)
- Proposed Approach to Regulatory Amendments to the Prohibition of Certain Toxic Substances Regulations, 2012, in consideration of the draft screening assessment for substituted diphenylamine substances, published on December 10, 2016 (Consultation Period closed)
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