Propane, 2-methyl- (containing 1,3-butadiene) (Isobutane containing 1,3-butadiene)
CAS Registry Number 75-28-5
Updated January 28, 2017:
A screening assessment of isobutane containing 1,3-butadiene was conducted in 2009 as part of the Challenge Initiative of the Chemicals Management Plan (CMP). The information provided in this Public Summary, such as the uses of this substance and sources of exposure, reflects the status of this substance at the time the assessment was completed.
The section of this Public Summary titled "What is the Government of Canada doing?" has been revised to communicate updates in risk management and related assessment activities. Butane in the absence of 1,3-butadiene, is being assessed for potential risk to human health and the environment as part of a group of substances referred to as Short-Chain Alkanes.
What is it?
- 2-Methylpropane, also known as isobutane, is an industrial chemical and also occurs naturally in oil and gas fields.
- Isobutane may contain very low amounts of 1,3-butadiene, which is produced during the refining of isobutane. 1,3-Butadiene was previously assessed by the Government of Canada and is considered to be harmful to human health.
How is it used?
- Isobutane is used as a solvent carrier, blowing/propellant agent, fuel or fuel additive and formulation component.
- Isobutane is also used in some products such as cosmetic/beauty preparations, air fresheners, cleaners, activator/primers and various coatings.
- Based on the most recent data available, isobutane containing very low amounts of 1,3-butadiene is manufactured and imported into Canada.
Why did the Government of Canada assess it?
- Isobutane was identified as a potential concern to human health based on its classification by international organizations as a substance which was found to cause cancer when it contains 0.1% or more of 1,3-butadiene, and based on what was believed to be a high potential for exposure to Canadians.
How are Canadians exposed to it?
- Canadians may be exposed to isobutane containing 1,3-butadiene from the use of products that contain isobutane as a propellant (for example, air fresheners). Exposure to 1,3-butadiene from these products is expected to be low.
- The Government of Canada conducted a science-based evaluation of isobutane containing 1,3-butadiene called a screening assessment.
- The Final Screening Assessment for Isobutane Containing 1,3-Butadiene was published in August 2009.
- Risk management activities for 1,3-butadiene from other sources are in place. The Government of Canada will examine the existing risk management activities so that they are appropriate and take into account any new information regarding exposure to 1,3-butadiene from isobutane containing 1,3-butadiene.
- In addition, isobutane (containing more than 0.1% of 1,3-butadiene) was added to Health Canada's Cosmetic Ingredient Hotlist in March 2011, which is an administrative list of substances that are restricted and prohibited in cosmetics.
- Isobutane in the absence of 1,3-butadiene is being assessed as part of a group of substances known as Short-Chain Alkanes.
What should Canadians do?
- The health risks associated with a substance depend on the hazard (its potential to cause health effects) and the amount of substance to which a person is exposed. Because Canadians' exposure to isobutane containing 1,3-butadiene is low, the Government of Canada is not currently recommending specific actions to reduce exposure.
- As a general precaution, Canadians are reminded when using any product to carefully follow any safety warnings and directions and to dispose of the products appropriately.
- Canadians who may be exposed to isobutane containing 1,3-butadiene in the workplace should consult with their employer and 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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