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:

• Publication of a Performance Measurement Evaluation for Risk Management of Isoprene

On this page

• Overview
• About this substance
• Human and ecological exposures
• Key health and ecological effects (hazard)
• Risk assessment outcomes
  • Screening assessment conclusions
• Preventive actions and reducing risk
  • Performance measurement
• 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 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.
  • 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.
• 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

• The Government of Canada published the Proposed Risk Management Approach for Isoprene on January 31, 2009 for a 60-day public comment period.
• In February 2011, isoprene was added to Schedule 1 of CEPA 1999, also called the List of Toxic Substances.
• To address concerns for human health, the following risk management actions were taken:
  • In June 2010, isoprene (referred to as isoprene monomer) was described on Health Canada's Cosmetic Ingredient Hotlist as a prohibited ingredient. The Hotlist is used to communicate that certain substances may not be compliant with requirements of the Food and Drugs Act or Cosmetic Regulations. Under Canadian legislation, cosmetics that contain substances that are harmful to the user cannot be sold.
• In June 2012, a notice requiring the preparation and implementation of pollution prevention (P2) plans for the synthetic rubber manufacturing sector in respect to isoprene was published. This was done to reduce human exposure to isoprene through the reduction of industrial emissions to the environment.
• Further information and updates on risk management actions for substances managed under the CMP can be found in the risk management actions table and the two year rolling risk management activities and consultations schedule.

Performance measurement

• The Government conducts performance measurement on the risk management of substances that are concluded to be toxic (harmful to human health and/or the environment) under CEPA 1999. This is done to determine whether actions taken to help protect human health or the environment are effective over time.
• On July 27, 2020, the Government published a Performance Measurement Evaluation for Risk Management of Isoprene. The evaluation concluded that the risk management actions taken have been successful in helping to protect the health of Canadians from concerns identified in the screening assessment, specifically from its release during the manufacturing of synthetic rubber. There is an ongoing need to continue to raise awareness of the negative health outcomes related to smoking.
• If new information becomes available on isoprene, such as exposure or hazard information, it will be considered through the Identification of risk assessment priorities process.

Related information

• Visit Do it for a Healthy Home for more information on chemical safety in and around the home.
• The screening assessment focused on potential risks from exposure of the general population of Canada, rather than occupational exposure. Hazards related to chemicals used in the workplace are defined within the Workplace Hazardous Materials Information System. For information concerning workplace health and safety and what steps to take in the workplace, Canadians should consult their employer and/or the Occupational Health and Safety Regulator in their jurisdiction.