PREPOD - information sheet

2-Propanone, reaction products with diphenylamine
CAS Registry Number 68412-48-6

Updated June 15, 2019:

The Final Screening Assessment for PREPOD was published on September 10, 2011 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:

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  • The Government of Canada conducted a science-based evaluation of PREPOD, called a screening assessment, to address the potential for harm to Canadians and to the environment.
  • 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 and 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 this screening assessment, it was concluded that PREPOD is entering or may enter the environment at levels that are harmful to the environment but not to human health.

About this substance

  • This screening assessment focused on the substance 2-Propanone, reaction products with diphenylamine, also referred to as PREPOD. It was assessed as part of Batch 11 of the Challenge initiative of the CMP.
  • PREPOD is a UVCB (Unknown or Variable Composition, Complex Reaction Products, or Biological Materials) substance, which contains a number of components that may range in concentrations making the composition variable or difficult to predict.
  • The Government gathered information on this substance, including details on its commercial status in Canada, to support the risk assessment and management of substances under the CMP.
  • PREPOD does not occur naturally in the environment.
  • At the time of the assessment, PREPOD was manufactured in Canada, and used as an ingredient in the manufacture of rubber products, including tires.

Human and ecological exposures

  • The assessment indicated that Canadians may be exposed to PREPOD at low levels due to dispersed environmental releases in air, drinking water, and soil. Exposure through use in products available to consumers, food or beverages was not expected.
  • PREPOD may be released to the environment as a result of industrial processes, such as its manufacture and use in production of rubber products, and during the use and disposal of products containing this substance.
  • Current exposures may be different from the time when the assessment was published.

Key health and ecological effects (hazard)

  • At the time of the assessment, there were limited data available for PREPOD as a whole substance. Therefore the assessment was based on information for several of the major components in PREPOD. In addition, information for a chemical similar to one of PREPOD’s components was used for assessing potential physical-chemical properties, persistence, bioaccumulation and ecological hazard through a comparative approach called read-across.
  • The “critical” or important effect used in the assessment for the characterization of risk to human health was haematotoxicity (slight lack of healthy red blood cells) induced by the component benzenamine, n-phenyl- (CAS RN 122-39-4).
  • The screening assessment indicated that PREPOD has the potential to cause harm to aquatic organisms. Components of PREPOD are persistent (they remain in the environment for a long time) and one of its components, diisopropyldimethylacridan (DIPDMA), also has the potential to accumulate in aquatic organisms.

Risk assessment outcomes

  • For the human health assessment, a comparison between levels to which Canadians may be exposed to PREPOD and levels associated with health effects determined that PREPOD is not considered to be harmful to human health.
  • Considering all information presented, it was determined that there is risk of harm to the environment from PREPOD and it meets the criteria for virtual elimination (set out in CEPA 1999).
  • The Government of Canada published the Final Screening Assessment for PREPOD on September 10, 2011.

Screening assessment conclusions

  • As a result of the screening assessment, the Government concluded that PREPOD is not harmful to human health.
  • However, the Government concluded that PREPOD is entering or may be entering the environment at levels that are harmful to the environment.
  • Components of PREPOD were concluded to meet the persistence criteria, and one significant component also met the bioaccumulative criteria, as set out in the Persistence and Bioaccumulation Regulations of CEPA 1999.

Preventive actions and reducing risk

Related information

  • Canadians who may be exposed to PREPOD 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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