Asphalt and oxidized asphalt – information sheet
- CAS Registry Number 8052-42-4 (asphalt)
- CAS Registry Number 64742-93-4 (asphalt, oxidized)
What are they?
- There are 2 substances included in the asphalt and oxidized asphalt assessment.
- These substances are produced at petroleum refineries during the distillation of crude oil and contain a complex mixture of large organic compounds with a high content of hydrocarbons.
- Their composition is variable, and therefore the properties of asphalt and oxidized asphalt vary with the source of the crude oil used and the refining and processing steps involved.
How are they used?
- Asphalt and oxidized asphalt are used primarily in the construction of roads and in roofing materials. They may also be found in adhesives and sealants, paints and coatings, and some other products available to consumers.
Why did the Government of Canada assess them?
- Asphalt and oxidized asphalt were identified as priorities for assessment through the categorization of substances on the Domestic Substances List.
- Asphalt and oxidized asphalt were included in the Petroleum Sector Stream Approach (Stream 4) under the Chemicals Management Plan for the screening assessment of potential risks to the environment and to human health.
How are Canadians exposed to them?
- Canadians may be exposed to asphalt and oxidized asphalt through inhalation in the vicinity of asphalt-producing industrial facilities and paving operations.
- Dermal exposure can occur from the use of certain products available to consumers, including during the application of asphalt-based pavement sealants.
- Long-term exposure to asphalt components may occur through ingestion of house dust, which includes asphalt components which may migrate indoors from asphalt surfaces.
How are they released into the environment?
- Asphalt and oxidized asphalt and/or their components can be released from spills in the form of liquid or aggregates (such as pavements), through leaching from paving and roofing products which contain asphalt, and from the manufacture of hot-mix asphalt and roofing products.
What are the results of the assessment?
- The Government of Canada conducted a science-based evaluation of asphalt and oxidized asphalt, called a screening assessment.
- Screening assessments address the potential for harm to the general population of Canada and to the environment. More information on types of approaches used to address substances can be found in the Risk Assessment Toolbox fact sheet.
- Because of their very low evaporation and water solubility, asphalt and oxidized asphalt are not expected to disperse in the environment or to be absorbed by living organisms.
- Exposure of the general population to asphalt and oxidized asphalt is low; therefore, they are not considered to constitute a risk to human health.
- The Government of Canada therefore concluded that asphalt and oxidized asphalt are not entering the environment at levels that constitute a danger to the environment.
- The Government of Canada also concluded that asphalt and oxidized asphalt are not harmful to human health at current levels of exposure.
What is the Government of Canada doing?
- The Government of Canada published the Final Screening Assessment for Asphalt and Oxidized Asphalt on August 26, 2017.
- Based on the conclusion of the final screening assessment, the Government of Canada proposes that no further action be taken on asphalt and oxidized asphalt.
- Volatile Organic Compounds (VOCs), which are released from asphalt formulations during their application, are already on the List of Toxic Substances in Schedule 1 of the Canadian Environmental Protection Act, 1999 (CEPA 1999), and actions are being taken to address releases of these compounds from different sources, including products which contain asphalt.
What can Canadians do?
- Under CEPA 1999, the risk posed by a substance is determined by considering both the hazardous properties (its potential to cause adverse human health or ecological effects) and the amount of exposure there is to people or the environment. Asphalt and oxidized asphalt are not a concern for the environment or human health at current levels of exposure.
- As a general precaution, Canadians are reminded when using any product to carefully follow safety warnings and directions and to dispose of the products appropriately.
- Canadians who may be exposed to asphalt and oxidized asphalt in the workplace should consult with their employer and occupational health and safety (OHS) representatives about safe handling practices, applicable laws, and requirements under OHS legislation and the Workplace Hazardous Materials Information System (WHMIS).
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