Butanone oxime - information sheet

2-Butanone, oxime

CAS Registry Number 96-29-7

Updated May 28, 2019:

The Final Screening Assessment for 2-Butanone, oxime (Butanone Oxime) was published on March 6, 2010, under the Challenge initiative of the Chemicals Management Plan (CMP). The assessment is summarized in this information sheet (formerly public summary) and has not changed. The section in this information sheet entitled "Preventive actions and reducing risk" communicates updates in risk management activities, namely:

  • Distribution of an information gathering initiative to inform the evaluation of progress achieved in reducing inhalation exposure to butanone oxime, through the code of practice.

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  • The Government of Canada conducted a science-based evaluation, called a screening assessment, to address the potential for harm to Canadians and to the environment from butanone oxime.
  • Under the Canadian Environmental Protection Act, 1999 (CEPA 1999), the risk posed by a substance is determined by considering both its hazardous properties (its potential to cause adverse human health or ecological effects) and the amount of exposure there is to people or the environment. A substance may have hazardous properties; however, the risk to human health or to the environment may be low depending upon the level of exposure.  
  • As a result of the screening assessment, the Government concluded that butanone oxime is harmful to human health, but not to the environment at levels of exposure that were current at the time of the assessment.

About this substance

  • This screening assessment focused on the substance 2-butanone, oxime, also referred to as butanone oxime or MEKO. This substance was assessed as part of Batch 7 of the Challenge initiative of the CMP.
  • According to information gathered by the Government, butanone oxime does not occur naturally.
  • At the time of the assessment, butanone oxime was used as an anti-skinning agent (used to prevent skin formation on the surface of stored products), in the formulation of alkyd paints (resin used in paints and in moulds for casting), varnishes, stains, and coatings.
  • It was also found in a number of pesticide products, namely wood preservatives and antifouling marine paints, and in some adhesives, silicone sealants, and printing inks. Butanone oxime was also used as a corrosion inhibitor (used to prevent corrosion) in industrial boilers and water treatment systems, as well as in the manufacturing process of urethane polymers.

Human and ecological exposures

  • The assessment indicated that Canadians may be exposed to butanone oxime from products available to consumers, mainly from the use of alkyd paint products.
  • Exposure of the environment to butanone oxime may occur through industrial releases through wastewater treatment systems.

Key health and ecological effects (hazard)

  • At the time of the assessment, the important or “critical” effects used for characterizing the risk to human health from butanone oxime were potential carcinogenicity, adverse effects on organs, and adverse effects on nose tissue.
  • Butanone oxime was considered to have a low to moderate potential to cause ecological effects.

Risk assessment outcomes

  • Based upon a comparison of levels to which Canadians may be exposed to butanone oxime and levels associated with health effects, it was determined that butanone oxime may pose a risk to human health.
  • Considering all the information presented in the ecological assessment, it was determined that butanone oxime does not pose a risk to the environment.
  • Also, butanone oxime was determined to meet the persistence criteria but not the bioaccumulation criteria as set out in the Persistence and Bioaccumulation Regulations of CEPA 1999.
  • The Government of Canada published the Final Screening Assessment for 2-Butanone, oxime (Butanone oxime) on March 6, 2010.

Screening assessment conclusions

  • The Government concluded that butanone oxime is harmful to human health at levels of exposure that were current at the time of the assessment.
  • The Government also concluded that butanone oxime is not entering the environment at levels that are harmful to the environment.

Preventive actions and reducing risk

Related information

  • Butanone oxime may be found in products available to consumers. Canadians should follow any safety warnings and directions on product labels and dispose of products responsibly.
  • Canadians who may be exposed to butanone oxime in the workplace should consult with their employer and an occupational health and safety (OHS) representative about safe handling practices, applicable laws, and requirements under OHS legislation and the Workplace Hazardous Materials Information System (WHMIS).
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