The Government of Canada conducted a science-based evaluation, called a screening assessment, to address the potential for harm to Canadians and the environment from 2 substances in the Arenes 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.
Cumene and DMBA are substances recognized as having hazardous properties; however, the risk to human health and the environment is low at current levels of exposure. The Government concluded that these substances are not harmful to human health or to the environment.
About these substances
The screening assessment focused on 2 of 9 substances referred to collectively under the Chemicals Management Plan (CMP) as the Arenes Group. The 2 substances addressed in this screening assessment are benzene, (1-methylethyl)- and benz[a]anthracene, 7, 12-dimethyl-. These are also referred to as cumene and 7, 12-dimethylbenz[a]anthracene (DMBA), respectively.
The Government gathers information on substances, including details on their commercial status in Canada, to support risk assessment and risk management of substances under the CMP.
In Canada, cumene is mainly used in industrial applications, for example, in the production of other substances and as a minor component in gasoline fuel and petroleum solvent. It is also used in and released from products available to Canadians, including adhesives, paints, automotive related products, and lubricants.
DMBA is used as a research or experimental chemical. It can also be produced unintentionally in industrial processes as a by-product.
Human and ecological exposures
In Canada, cumene has been measured and reported in indoor air, which is the primary source of exposure of Canadians. People may also be exposed to cumene from the environment (for example, outdoor air) and food; however, these exposures are considered to be minimal. Releases of cumene to air have been reported to the National Pollution Release Inventory (NPRI).
Canadians can also be exposed to cumene through the use of various products available to consumers that contain this substance. Direct exposure to cumene during the application or use of products is expected to be infrequent.
Ambient (outdoor) air is a possible source of exposure of Canadians to DMBA. Releases to air from a few industry sectors have been reported to the NPRI. Measured levels of the substance in air, however, are negligible.
Cumene and DMBA were identified according to information considered in the ERC Approach as substances that have a low ecological exposure potential.
Key health and ecological effects (hazard)
The International Agency for Research on Cancer classified cumene as “possibly carcinogenic to humans” and it was recommended by the United States National Toxicology Program that cumene is reasonably anticipated to be a human carcinogen (able to cause cancer). Specifically, laboratory studies identified cumene as a potential carcinogen when exposure occurs through inhalation over the long-term. Laboratory studies also showed that repeated exposure to cumene through oral and inhalation routes of exposure resulted in effects on the liver and kidney, respectively.
DMBA has been identified as genotoxic and carcinogenic through laboratory studies.
For both cumene and DMBA, carcinogenicity was considered to be the important or “critical” effect used for characterizing the risk to human health in this assessment. For cumene, liver and kidney effects were also considered.
According to information considered in the ERC Approach, cumene and DMBA were both identified as substances with low ecological hazard potential.
Risk assessment outcomes
Using a comparison of levels to which Canadians can be exposed, and levels associated with health effects, it was determined that the risk to human health from either cumene or DMBA is low.
The ERC Approach characterized cumene and DMBA as posing a low risk to the environment.
The Government concluded that cumene and DMBA are not harmful to human health at current levels of exposure.
The Government also concluded that cumene and DMBA are not entering the environment at levels that are harmful to the environment.
Preventive actions and reducing risk
Although these substances are not considered to be harmful to human health or the environment at current levels of exposure, these substances are considered to have potential human health effects of concern. There may be a concern for human health if exposure to these substances were to increase.
For these reasons, follow-up activities to track changes in exposure and/or commercial use patterns for cumene and DMBA will include:
monitoring the outcome of existing Health Canada research underway of cumene in indoor air
continued monitoring of cumene and DMBA reported to the NPRI, and
information gathering, such as mandatory or voluntary surveys, under section 71 of CEPA 1999.
Cumene can be found in products available to consumers. Canadians should follow any safety warnings and directions on product labels and dispose of products responsibly.
Canadians who may be exposed to cumene or DMBA in the workplace should 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).