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Benzenamine, N-phenyl-, Reaction Products with Styrene and 2,4,4-Trimethylpentene (BNST)

CAS Registry Number 68921-45-9

What is it?

  • Benzenamine, N-phenyl-, Reaction Products with Styrene and 2,4,4-Trimethylpentene, also known as BNST, is an industrial chemical.

How is it used?

  • BNST is used as a lubricant antioxidant additive in vehicle engine oils and commercial/industrial lubricants.
  • Based on the most recent data available, BNST is manufactured and imported into Canada. It is not naturally produced in the environment.

Why did the Government of Canada assess it?

  • BNST was identified as a potential concern to the environment based on available information regarding possible persistence, accumulation in organisms and potential to cause harm to organisms.

How is it released into the environment?

  • Small amounts of BNST may be released to surface water or sewers as a result of manufacturing of the substance and blending of lubricating oils.
  • A small portion of the BNST used may be released to sewers and soil due to leaks from vehicle engines and other equipment. A small portion may also be placed into waste disposal sites.
  • When BNST is released, it remains in the environment for a long time. It also has the potential to build up to high levels in the bodies of organisms.

What is the Government of Canada doing?

  • The Government of Canada has conducted a science-based evaluation of BNST called a screening assessment.
  • The Government of Canada has concluded that BNST is entering or may enter the environment in a quantity or under conditions that may constitute a danger to the environment.
  • BNST also meets the criteria for persistence and bioaccumulation as defined in the Persistence and Bioaccumulation Regulations made under the Canadian Environmental Protection Act, 1999 (CEPA 1999).
  • The final screening assessment and proposed risk management approach were published on August 1, 2009. The proposed risk management approach will be subject to a 60-day comment period (from August 1, 2009 to September 30, 2009).