Dechlorane plus - information sheet 

1,4:7,10-Dimethanodibenzo[a,e]cyclooctene, 1,2,3,4,7,8,9,10,13,13,14,14-dodecachloro-1,4,4a,5,6,6a,7,10,10a,11,12,12a-dodecahydro-(DP)
CAS Registry Number 13560-89-9

Publications summarized:

• Final Screening Assessment for DP (published on May 11, 2019)
• Associated notice: Canada Gazette, Part I: Vol. 153, No. 19 – May 11, 2019

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 risk reduction
• 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) 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 by both 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 applies risk management instruments under CEPA and other federal acts to help prevent or reduce potential harm.
• As a result of the screening assessment, the Government concluded that DP is not harmful to human health; however, it is harmful to the environment at levels of exposure considered in the assessment. DP may cause effects in sediment and soil organisms at low concentrations. Risk management actions have been proposed or taken to help reduce risk to the environment.

About this substance

• The screening assessment focused on 1 of 10 substances referred to collectively under the Chemicals Management Plan (CMP) as the Certain Organic Flame Retardants Substance Grouping, which includes organic substances having similar function: application to materials to slow the ignition and spread of fire.
• The substance addressed in the assessment is 1,4:7,10-dimethanodibenzo[a,e]cyclooctene, 1,2,3,4,7,8,9,10,13,13,14,14-dodecachloro-1,4,4a,5,6,6a,7,10,10a,11,12,12a-dodecahydro-, also referred to as dechlorane plus or DP.
• DP does not occur naturally in the environment. According to information gathered by the Government, DP is used in Canada as an additive flame retardant in several applications, which may include wire and cable jacketing, electronics, appliances, automobiles, hard plastic connectors, and plastic roofing materials.

Human and ecological exposures

• The main sources of exposure for people in Canada are expected to be from the environment (for example from air, dust, soil, and water), and food, including human milk.
• DP may be released to the Canadian environment during the manufacturing, formulation or industrial use stages of a substance and products containing DP.
• Releases to the environment are expected to occur primarily through wastewater, with some release to water directly from industrial sites.

Key health and ecological effects (hazard)

• On the basis of the available information, no effects on human health were identified.
• There were limited soil and sediment ecotoxicity data, therefore, a comparative approach using similar chemicals, called read-across, was used for assessing potential environmental effects. Using data available for related substances, results suggest that DP may cause effects at low concentrations in sediment and soil organisms.

Risk assessment outcomes

• Given the information available, including estimates of intake from the environment and food, the risk to human health from DP is considered to be low.
• However, it was also determined that there is risk of harm to the environment from DP.

Screening assessment conclusions

• The Government concluded that DP is not harmful to human health at levels of exposure considered in the assessment.
• However, the Government concluded that DP is entering or may enter the environment at levels that are harmful to the environment.
• It was also determined that DP meets the persistence and bioaccumulation criteria as set out in the Persistence and Bioaccumulation Regulations of CEPA.

Preventive actions and risk reduction

• On February 26, 2025, DP was added to Part 2 of Schedule 1 to CEPA. Adding a substance to Schedule 1 does not restrict its use, manufacture or import. Rather, it enables the Government to take enforceable risk management actions under.
  • Toxic substances that pose the highest risk (that is, meet certain criteria) are added to Part 1 of Schedule 1. These are prioritized for total, partial, or conditional prohibition.
  • Other toxic substances are added to Part 2 of Schedule 1 and are prioritized for pollution prevention actions, which may include prohibition.
  • Regulations specifying criteria for the classification of substances that pose the highest risk or that are carcinogenic, mutagenic or toxic to reproduction will be developed. When criteria are available, some substances considered for addition to Part 2 of Schedule 1 may instead be considered for addition to Part 1 of Schedule 1.
• The Government published the Proposed Risk Management Approach for DP on May 11, 2019 for a 30-day public comment period.
• Risk management actions and consultations that have or will take place, including use of the proposed Prohibition of Certain Toxic Substances Regulations, 2022 for DP, are outlined in the Risk management action milestones section of the Certain Organic Flame Retardants Substance Grouping page.
• Additionally, nominating DP as a chemical of mutual concern under Annex 3 of the Canada – United States Great Lakes Water Quality Agreement will be pursued, as a means of addressing transboundary releases of DP, which may contribute to environmental exposure in Canada.

Where to find updates on risk management actions

• The Government is taking risk management actions on DP to address ecological concerns. Updates on actions can be found on the timeline for the Certain Organic Flame Retardants substance Grouping.
• Up-to-date information on the Prohibition of Certain Toxic Substances Regulations, 2022 (proposed), and additional information on the risk management of substances as well as a table of risk management actions for 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

• A summary of the risk assessment and management of flame retardant substances, under the CMP, is available.
• Assessments conducted under CEPA focus on risks of exposure of the general population. Hazards related to chemicals used in the workplace are defined within the Workplace Hazardous Materials Information System (WHMIS). If a substance is harmful to the general population, it could also be of concern for individuals in situations where a higher volume of the substance is used or where the substance is used for a longer duration (for example, the workplace). The Government of Canada recognizes that it is the responsibility of the federal, provincial and territorial occupational health and safety organizations to coordinate legislation for the safe use of chemicals in the workplace. We are working to support this role by integrating the information, tools, and technical expertise of the CMP and Health Canada's Workplace Hazardous Products Program.