Isoprene - information sheet

1,3-Butadiene, 2-methyl-
CAS Registry Number78-79-5

Updated July 27, 2020

The Final Screening Assessment for Isoprene was published on January 31, 2009 under the Challenge initiative of the Chemicals Management Plan (CMP). The assessment is summarized in this information sheet 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, called a screening assessment, to address the potential for harm to Canadians and to the environment from isoprene.
  • 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.
  • Isoprene was identified as a potential concern to human health based on a classification by an international organization for causing cancer and genetic effects in laboratory studies. Isoprene was also believed to have a high potential for exposure to Canadians. As this substance did not meet the criteria for persistence, bioaccumulation or inherent toxicity to aquatic organisms, the focus of the screening assessment was on human health.
  • As a result of the screening assessment, the Government concluded that isoprene may be harmful to human health but not to the environment, at levels of exposure considered in the assessment.

About this substance

  • The screening assessment summarized here focused on the substance 1,3-butadiene, 2-methyl-, also referred to as isoprene. It was assessed as part of Batch 2 of the Challenge initiative of the CMP.
  • Isoprene is an industrial chemical (human-made) but is also produced naturally by plants and humans.
  • According to information gathered by the Government, at the time of the assessment, isoprene was used in the manufacture of other substances, rubbers, and plastics, which were used to make vehicle tires and a variety of products, including paint resin, footwear, adhesives, and molded goods, among other things. Isoprene is also found in tobacco smoke.

Human and ecological exposures

  • According to the screening assessment, isoprene is emitted into the environment from both natural and human-made sources, thus the main source of exposure to Canadians would be from air, with cigarette smoking expected to be the primary source of isoprene to indoor air. While there were some reports of isoprene uses in products available to consumers, these exposures were expected to be very low.
  • The assessment considered data on the releases of isoprene to air from industrial facilities in Canada reported in the National Pollutant Release Inventory (NPRI).

Key health and ecological effects (hazard)

  • To inform the health effects characterization in the screening assessment, international reports of data were considered. Critical effects used for characterizing the risk to human health in the assessment were carcinogenicity (potential to cause cancer) and effects in the thymus.
  • Experimental ecotoxicological data indicated that isoprene does not cause significant harm to aquatic organisms at low concentrations.

Risk assessment outcomes

  • Based upon a comparison of levels to which Canadians may be exposed to isoprene from indoor air and levels associated with health effects, it was found that isoprene may pose a risk to human health.
  • Considering the information presented in the assessment, it was determined that there is low risk of harm to the environment from isoprene.
  • The Government of Canada published the Final Screening Assessment for Isoprene on January 31, 2009.

Screening assessment conclusions

  • As a result of the screening assessment, the Government concluded that isoprene may be harmful to human health at levels of exposure considered in the assessment.
  • The Government also concluded that isoprene is not entering the environment at levels that may be harmful to the environment.
  • Also, isoprene does not meet the persistence or the bioaccumulation criteria as set out in the Persistence and Bioaccumulation Regulations of CEPA 1999.

Preventive actions and reducing risk

Performance measurement

Related information

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