Alkyl Aryl Phosphites Group - information sheet

Phosphorus acid, 2-ethylhexyl diphenyl ester (2-Ethylhexyl diphenyl phosphite; EHDPP) 
CAS Registry Number 15647-08-2

Phosphorus acid, diisodecyl phenyl ester (Diisodecyl phenyl phosphite; DIDPP) 
CAS Registry Number 25550-98-5

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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 substances in the Alkyl Aryl Phosphites Group.
  • 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.
  • The ecological hazard and exposure potentials of these 2 substances were classified using the Ecological Risk Classification of Organic Substances Approach.
  • As a result of this screening assessment, it was found that the risk posed by either 2-ethylhexyl diphenyl phosphite (EHDPP) as well as diisodecyl phenyl phosphite (DIDPP), is low at current levels of exposure. Therefore, the Government concluded that these 2 substances are not harmful to human health or to the environment.

About these substances

  • This screening assessment focused on 2 substances referred to collectively under the Chemicals Management Plan (CMP) as the Alkyl Aryl Phosphites Group.
  • The substances are phosphorus acid, 2-ethylhexyl diphenyl ester (commonly referred to as 2-ethylhexyl diphenyl phosphite or EHDPP) and phosphorus acid, diisodecyl phenyl ester (commonly referred to as diisodecyl phenyl phosphite or DIDPP).
  • The Government gathers information on substances, including details on sources and uses in Canada, to support the risk assessment and management of substances under the CMP. Both EHDPP and DIDPP are primarily used as secondary antioxidants (process stabilizers) for processing polymeric or plastic materials (for example, polyvinyl chloride).

Human and ecological exposures

  • Since small amounts of EHDPP and DIDPP may remain as part of manufactured plastic items or products available to consumers, Canadians may be exposed to these substances through contact with these items.
  • The presence of these 2 substances in the environment (for example, air, water, or soil) is expected to be minimal.
  • Both EHDPP and DIDPP were identified according to information considered under the Ecological Risk Classification of Organic Substances Approach as having low ecological exposure potential.

Key health and ecological effects (hazard)

  • For the human health assessment, specific effects on organs were not identified for these substances.
  • According to information considered under the Ecological Risk Classification of Organic Substances Approach, EHDPP was identified as having a low ecological hazard potential while that of DIDPP was identified as high, because of its toxicity and potential to accumulate in aquatic organisms.

Risk assessment outcomes

  • Based upon a comparison of levels to which Canadians may be exposed, and levels associated with health effects, the risk to human health from either EHDPP or DIDPP is low.
  • Based on the outcome of the Ecological Risk Classification of Organic Substances Approach, these 2 substances are considered unlikely to cause ecological harm. 
  • The Government of Canada published the Final Screening Assessment for the Alkyl Aryl Phosphites Group on February 2, 2019.

Screening assessment conclusions

  • As a result of this assessment, the Government concluded that EHDPP and DIDPP are not harmful to human health at current levels of exposure and that these 2 substances are not entering the environment at levels that are harmful to the environment.

Related information

  • These 2 substances can be found in trace amounts in plastic items or products that are 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 these substances in the workplace can 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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