Carboxylic Acid Anhydrides Group - information sheet

• 1,3-Isobenzofurandione (Phthalic anhydride)
  CAS Registry Number 85-44-9

• 2,5-Furandione (Maleic anhydride)
  CAS Registry Number 108-31-6

• 5-Isobenzofurancarboxylic acid, 1,3-dihydro-1,3-dioxo- (Trimellitic anhydride)
  CAS Registry Number 552-30-7

On this page

• Overview
• About these substances
• Human and ecological exposures
• Key health and ecological effects (hazard)
• Risk assessment outcomes
  • Screening assessment conclusions
• Related information

Overview

• 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 3 substances in the Carboxylic Acid Anhydrides 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.
  • More information on assessing risk can be found in the Overview of Risk Assessment and related fact sheets, particularly on Types of Risk Assessment Documents and the Risk Assessment Toolbox.
• The ecological hazard and exposure potentials of these 3 substances were classified using the Ecological Risk Classification of Organic Substances Approach.
• Although phthalic anhydride, maleic anhydride and trimellitic anhydride have health effects; the risk to Canadians is low, and they are considered to have a low ecological hazard potential. Therefore, it is concluded that none of these 3 substances are harmful to human health or the environment at current levels of exposure.

About these substances

• This screening assessment focused on 3 of the 8 substances referred to collectively as the Carboxylic Acid Anhydrides Group, under the Chemicals Management Plan (CMP). The substances addressed in this screening assessment are phthalic anhydride, maleic anhydride and trimellitic anhydride.
• The other 5 substances in the Carboxylic Acid Anhydrides Group were determined to be of low concern to both human health and the environment, through other approaches. Conclusions for CAS RNs 85-42-7, 26544-38-7, 28777-98-2, 32072-96-1and 68784-12-3 are provided in the Screening Assessment for Substances Identified as Being of Low Concern using the Ecological Risk Classification of Organic Substances and the Threshold of Toxicological Concern (TTC)-based Approach for Certain Substances .
• According to information gathered by the Government, these 3 substances are man-made and they do not occur naturally in the environment.  In Canada, they are primarily used in the manufacture of other chemicals.  
• Phthalic anhydride is primarily used to manufacture phthalate esters. It may also be used in the production of polyester resins, alkyd resins, and other substances such as pigments and dyes. In Canada, phthalic anhydride is present in spray paint products, floor polishes and cosmetic products, including nail polishes and eyelash adhesives. It may also be used as a component in the manufacture of food packaging materials; however, exposure from this use is considered negligible.
• Maleic anhydride is primarily used in the manufacture of unsaturated polyester resins as well as other chemical substances. In Canada, maleic anhydride was identified as an ingredient in shampoos, temporary tattoos, exfoliants, bubble baths (foam and oil), bath salts, and body cleansers. It was also identified in blending-sticks designed to repair minor scratches on wood surfaces. Maleic anhydride may also be used as a component in the manufacture of food packaging materials.
• Trimellitic anhydride is used in commercial applications (such as paints and coatings, and plastic and rubber materials). It may also be used as a component in resins used to manufacture recyclable bottles (for example, milk, water and juice bottles). Trimellitic anhydride is also an ingredient found in nail polish.

Human and ecological exposures

• Canadians may be exposed to phthalic anhydride from the use of products available to consumers including spray paints, floor polishes, and eyelash adhesives. Exposure may also occur through indoor air and dust.
• Canadians may be exposed to maleic anhydride from the use of products available to consumers, including shampoos, temporary tattoos, exfoliants, bubble baths (foam and oil), bath salts, and body cleansers.
• The overall exposure of Canadians to trimellitic anhydride is expected to be negligible.
• The National Pollutant Release Inventory (NPRI) reported small releases of phthalic anhydride and maleic anhydride to the environment.
• According to information considered under the Ecological Risk Classification of Organic Substances Approach both phthalic anhydride and trimellitic anhydride were identified as having a low ecological exposure potential. However, maleic anhydride was identified as having a high ecological exposure potential based on large reported quantities and persistence in air.

Key health and ecological effects (hazard)

• To identify health effects information, international reports of data on these substances were reviewed. The 3 substances were assessed by the Organisation for Economic Cooperation and Development (OECD) Cooperative Chemicals Assessment Programme.
• For phthalic anhydride, respiratory sensitization was considered to be the important or “critical” effect used for characterizing the risk to human health in this assessment.
• For maleic anhydride, effects on the kidney and bladder were considered to be the important or “critical” effect used for characterizing the risk to human health.
• Based on the OECD assessment report for trimellitic anhydride, the principal effects were to the immune system and to the lungs.
• According to information considered under the Ecological Risk Classification of Organic Substances Approach, all 3 substances in this group were identified as having low ecological hazard potential.

Risk assessment outcomes

• Based upon a comparison of levels to which Canadians can be exposed to and levels associated with health effects, it was determined that the risk to human health from phthalic anhydride and maleic anhydride is low.
• Exposure of Canadians to trimellitic anhydride is expected to be negligible; therefore the risk to human health is low.
• Based upon the outcome of the Ecological Risk Classification of Organic Substances Approach, these 3 substances are considered unlikely to cause ecological harm.
• The Government of Canada published the Final Screening Assessment for Carboxylic Acids Anhydrides Group on March 9, 2019.

Screening assessment conclusions

• As a result of this assessment, the Government concluded that phthalic anhydride, maleic anhydride and trimellitic anhydride are not harmful to human health at current levels of exposure.
• The Government also concluded that these 3 substances are not entering the environment at levels that are harmful to the environment.

Related information

• These 3 substances can be found in certain products available to consumers. Canadians should follow any safety warnings and directions on product labels and dispose of products responsibly.
• Visit Healthy Home for more information on chemical safety in and around the home.
• 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).