Alkyl Halides Group - information sheet

Updated March 17, 2021:

• Draft Screening Assessment for Alkyl Halides Group (published on March 5, 2022 for a 60-day public comment period ending on May 4, 2022)
• Risk Management Scope for the Alkyl Halides Group, specifically: Propane, 1-bromo- (1-bromopropane) (Published on March 5, 2022 for a 60-day public comment period ending on May 4, 2022). Risk management is proposed.
• Associated notice: Canada Gazette, Part I: Vol. 156, No. 10 – March 5, 2022

On this page

• Overview
• About these substances
• Human and ecological exposures
• Key health and ecological effects (hazard)
• Risk assessment outcomes
  • Proposed screening assessment conclusions
• Preventive actions and risk reduction
  • Additional considerations
  • Where to find updates on risk management actions
• Related resources

Overview

• The Government of Canada conducts risk assessments of substances under the Canadian Environmental Protection Act, 1999 (CEPA 1999) to determine whether they present or may present a risk to human health or to the environment.
  • The risks posed by a substance are determined both by its hazardous properties (potential to cause adverse human health or ecological effects) and the amount or extent of exposure to people and the environment.
  • When needed, the Government implements risk management measures under CEPA 1999 and other Federal Acts to help prevent or reduce potential harm.
• The ecological hazard and exposure potentials of these 4 substances were classified using the Ecological Risk Classification of Organic Substances (ERC) Approach.
• The Government is proposing that 1-bromopropane may be harmful to human health due to potential exposure from products available to consumers and its association with developmental effects. 1-Bromopropane is also associated with neurotoxicity and potential carcinogenicity.
• The Government is proposing regulatory and/or non-regulatory actions to help reduce potential human exposures to 1-bromopropane.
• Some of the substances in the Alkyl Halides Group are associated with health effects, including developmental toxicity and cancer (chloroethane), changes to cells in the nasal cavity (bromoethane), and the potential to cause cancer (bromoethane).

None of the substances in this group are proposed to be harmful to the environment, at levels of exposure considered in the assessment.

About these substances

• The summary of publications for the Alkyl Halides Group timeline includes details on the substance names and CAS Registry Numbers (RNs).
• The screening assessment focuses on 4 of 8 substances referred to as the Alkyl Halides Group under the third phase of the Chemicals Management Plan (CMP).
• The other 4 substances are aryl halides and were determined to be of low concern to human health and the environment through other approaches. The conclusion for the substance with the CAS RN 77-47-4 is provided in the Final Screening Assessment for Substances Identified as Being of Low Concern using the Ecological Risk Classification of Organic Substances and the Threshold of Toxicological Concern (TTC)-based Approach for Certain Substances. The conclusions for the substances with the CAS RNs 74-88-4, 126-99-8 and 630-20-6 are provided in the Final Screening Assessment for the Rapid Screening of Substances with Limited General Population Exposure.
• Trans-1,2-dichloroethane was considered a priority for risk assessment based on the results of the identification of risk assessment priorities process.
• The 4 substances included in the Alkyl Halides Group are human-made. Bromoethane and 1-bromopropane are also naturally occurring.
• According to information gathered by the Government, the 4 substances in the Alkyl Halides Group are mainly used in Canada in products available to consumers, such as liquid or aerosol cleaners or degreasers, aerosol starting fluids (engine starting aid), air conditioning flush, silicone mold release spray, and spray foam insulation.

Human and ecological exposures

• The screening assessment indicates that Canadians may be exposed to the 4 substances included in the Alkyl Halides Group through environmental sources, such as indoor and ambient air.
• The main source of exposure to bromoethane is from indoor and ambient air. Bromoethane is not anticipated to be found in products available to consumers.
• The main source of exposure to chloroethane is from indoor and ambient air, and the use of starting fluid spray.
• The main source of exposure to trans-1,2-dichloroethane is from indoor and ambient air and the use of textile spot cleaners.
• 1-Bromopropane exposure is expected from indoor air, and the use of silicone mold release spray, electronic cleaner spray and automotive air conditioning flush.
• According to the information considered under the ERC Approach, bromoethane and 1-bromopropane were identified as having low ecological exposure potential, while chloroethane and trans-1,2-dichloroethane were classified as having a high ecological exposure potential based on a long half-life in air and a large annual import quantity.

Key health and ecological effects (hazard)

• To inform the health effects characterization in the draft screening assessment, international reports of data on these substances were considered. This includes assessments by the Organisation for Economic Co-operation and Development (OECD) and the United States Environmental Protection Agency, among others. These reviews were used to inform the health effects characterization in the screening assessment.
• Bromoethane has been classified by the European Chemicals Agency (ECHA) as "suspected of causing cancer", in the Global Harmonized System (GHS). Changes to cells in the nasal cavity, and the potential to cause cancer were considered to be critical effects considered in the risk assessment.
• Chloroethane has been classified by ECHA as "suspected of causing cancer" in the GHS. The critical effect identified to characterize risk to human health for chloroethane was developmental toxicity and cancer.
• The critical effect identified to characterize the risk to human health for trans-1,2-chloroethane was immunotoxicity.
• 1-Bromopropane has been classified by the International Agency for Research on Cancer (IARC) as "possibly carcinogenic". This substance was also classified by ECHA as a "presumed reproductive toxicant" in the GHS. The critical effects identified for characterizing risk to 1-bromopropane include developmental effects, neurotoxicity and cancer.
• According to information considered under the ERC Approach, trans-1,2-dichloroethane was identified as having a low ecological hazard potential while bromoethane, chloroethane and 1-bromopropane were identified as having moderate ecological hazard potentials based on increased level of ecotoxicity.

Risk assessment outcomes

• Based upon a comparison of levels to which Canadians may be exposed to 1-bromopropane from certain products available to consumers, and levels associated with health effects, it was determined that this substance may pose a risk to human health.
• It was determined that the risk to human health from bromoethane, chloroethane and trans-1,2-chloroethane is low. This was based upon a comparison of levels to which Canadians may be exposed to each of these substances, and levels associated with health effects.
• Based upon the outcome of the ERC Approach, all 4 substances assessed are considered unlikely to be causing ecological harm.

Proposed screening assessment conclusions

• The Government is proposing that 1-bromopropane may be harmful to human health at levels of exposure considered in the assessment; however, it is proposing that the other 3 substances are not harmful to human health at levels of exposure considered in the assessment.
• The Government is also proposing that all 4 substances are not entering the environment at concentrations that are harmful.
• 1-Bromopropane is proposed to meet the persistence criteria, but not the bioaccumulation criteria, as set out in the Persistence and Bioaccumulation Regulations of CEPA 1999.

Preventive actions and risk reduction

• If the proposed conclusion is confirmed in the final screening assessment, the Government will consider adding 1-bromopropane to Schedule 1 of CEPA 1999, also called the List of Toxic Substances. Adding a substance to the list does not restrict its use, manufacture or import. Rather, it enables the Government to take risk management actions under CEPA 1999.
• Publication of the risk management scope aims to inform stakeholders of proposed risk management options and initiate discussion about their development. The Government will consider the following actions to help address human health concerns:
  • Regulatory and/or non-regulatory measures to help reduce inhalation exposures to 1-bromopropane contained in certain products available to consumers such as automotive air conditioning flush, silicone mold release spray and electronics cleaner spray.
• Information is being sought by the Government to inform risk management decision-making. Details can be found in the risk management scope, including where to send information during the public comment period, ending May 4, 2022.
• Risk management actions may evolve through consideration of assessments and risk management actions published for other substances. This is to ensure effective, coordinated, and consistent risk management decision-making.

Additional considerations

• Although a risk to human health or the environment has not been identified at current levels of exposure, there may be a concern if exposure to bromoethane and chloroethane were to increase. As a result, these substances may be considered in future initiatives to track their commercial status or identify new uses.

Where to find updates on risk management actions

• Additional information on the risk management of substances addressed under the CMP is available.
• Use the Substances Search tool to find substances that are referenced in certain legislative or regulatory instruments or on Government of Canada websites.

Related resources

• Substances within the Alkyl Halides Group may be found in products available to consumers. Canadians should follow any safety warnings and directions related to the product and dispose of products responsibly.
• Visit Do it for a Healthy Home for more information on chemical safety in and around the home, including more information on 1-bromopropane (for consumers).
• 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 (WHMIS). 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.