Archived Group profile for Phthalates

October 2011

Group Description

• This group consists of diesters of 1,2-benzenedicarboxylic acid, also known as ortho-phthalates.
• Fourteen substances are being considered for inclusion in this group and are identified in Table 1. The scope of this group may be expanded to inform a cumulative assessment approach if warranted.
• Within the phthalates group assessment, there are 3 potential sub-groups based on structure-activity (observed differences in developmental toxicity):
  • Low molecular weight (MW) (R-alkyl backbone of 3 or less carbon atoms (≤C3).
  • Intermediate MW [R-alkyl backbone of 4 to 6 carbon atoms (C4 to C6)].
  • High MW (R-alkyl backbone of 7 or more carbon atoms (≥C7), or a benzyl group).
• From an ecological perspective, the initial approach may be to view the substances as a single broad group, with subgroups based on properties such as P, B, log K_ow emerging early on in the assessment process.

Selection Considerations

• Potential health effects of concern. Some phthalates have been identified as potentially associated with reproductive and developmental effects^{Footnote 2}.
• Potential ecological effects of concern for some phthalates^{Footnote 3a}.
• Potential exposure of consumers and children. A survey conducted for phase 1 of the Domestic Substances List (DSL) Inventory Update identified that a subset of phthalates have a wide range of consumer applications including: adhesives and sealants, paints and coatings, plastic and rubber materials, and automotive parts, which could result in exposure to humans, including children^{Footnote 4}.
• Potential to leverage/align with international activity. Phthalates have been identified both domestically and internationally as priorities for assessment. For example,
  • In 2008, the United States National Research Council published a key document, Phthalates and Cumulative Risk Assessment: The Tasks Ahead, making the case for cumulative assessment^{Footnote 5}.
  • In 2009, the United States Environmental Protection Agency (US EPA) released an Action Plan for phthalates which includes conducting an assessment of phthalates under the Integrated Risk Information System (IRIS) program^{Footnote 3b}.
  • United States Consumer Product Safety Commission Chronic Hazard Advisory Panel will conduct a cumulative hazard assessment of phthalates (expected completion 2012)^{Footnote 6}.
• Potential risk assessment and risk management efficiencies and effectiveness.
  • Assessing as a group allows for consideration of aggregate exposure and cumulative risk, where warranted, and may inform potential substitution and to avoid repeated product formulation changes over time.

Potential Sectoral Involvement Identified through Phase 1 of the DSL Inventory Update

• Plastic and rubber manufacturers
• Automotive manufacturing
• Chemical (except agricultural) wholesaler distributors
• Adhesive and sealants manufacturers
• Petroleum and Coal Product Manufacturing

Footnotes