> The Ontario Line - Environment | Metrolinx Engage


The Ontario Line - Environment

By its nature, providing reliable, safe and accessible public transportation brings environmental and social benefits. Metrolinx is committed to the preservation and protection of the environment, while working to provide an integrated and sustainable transportation system. To maintain strong environmental oversight, Metrolinx is conducting a thorough environmental assessment – including studying existing environmental conditions and completing an environmental impact assessment. The below graphic shows the different environmental conditions that have been studied throughout the Ontario Line study area and the different reports that we will use to share those findings.


Metrolinx is completing an environmental assessment (EA) in accordance with Ontario Regulation 341/20: Ontario Line Project (O. Reg. 341/20) made under the Environmental Assessment Act. This regulation was available for public review from February 18, 2020 to March 19, 2020 on the Environmental Registry of Ontario and came into force on June 30, 2020.

The regulation outlines a Project-specific EA process that includes:

  • Public, regulatory agency and Indigenous community notification and consultation
  • An Environmental Conditions Report and an Environmental Impact Assessment Report
  • An opportunity for Early Works Reports for assessment of works that are ready to proceed in advance of Environmental Impact Assessment
  • Report completion
  • Metrolinx addressing concerns through an issues resolution process

In keeping with the process outlined in O. Reg. 341/20, Metrolinx is advancing Environmental Conditions, Early Works and Environmental Impact Assessment Reports.

The Environmental Conditions Report (ECR) characterizes environmental conditions within the Ontario Line study area through a combination of desktop review and field studies in accordance with industry standard techniques, protocols and guidelines.

In accordance with O. Reg. 341/20, the ECR provides the following on the Ontario Line Project:

  • A statement of the purpose and a summary of background information
  • A description of the Project
  • A map showing the area studied
  • A description of the local environmental conditions in the area studied
  • A description of all studies undertaken
  • A preliminary description of the potential impacts that the Project might have on the environment that have been identified to date and an indication of how those impacts will be studied and described in further detail in the Environmental Impact Assessment Report
  • A description of any potential measures for mitigating any negative impacts that the Project might have on the environment
  • A description of the future studies that will be carried out as part of the Environmental Impact Assessment Report to determine potential impacts to the environment caused by the Project and the potential measures for mitigating any negative impacts in respect of them
  • A preliminary list of the potential municipal, provincial, federal or other approvals or permits that may be required for the Project
  • A consultation record

Public feedback received on the Draft Environmental Conditions Report has been incorporated into the final version of the report. If you have questions about the report or about the environmental assessment process for the Ontario Line, please contact us.

As project planning and design advance, Metrolinx will complete and publish Early Works Report(s) and an Environmental Impact Assessment Report. Potential impacts and mitigation measures identified in the ECR will be confirmed and refined within Early Works Report(s) and the Environmental Impact Assessment Report.

Study Area

A broad study area was chosen to support flexibility in design. The Environmental Conditions Report summarizes potential impacts and potential mitigation measures for consideration during project planning and design.

map graphic showing the study area for the Ontario Line Environmental Reports

The Ontario Line study area has been divided into three segments:

  • Ontario Line West
    (OLW - from approximately Dufferin Street to University Avenue)
  • Ontario Line South
    (OLS - from University Avenue to Danforth Avenue)
  • Ontario Line North
    (OLN - from Danforth Avenue to approximately Eglinton Avenue East)

As detailed design advances, potential impacts and mitigation measures will be confirmed. These details as well as supporting studies will be included in the Early Works Reports and/or Environmental Impact Assessment Report.

View the Full Environmental Conditions Report

View the Environmental Conditions Report studies:

Early works are components of the Ontario Line Project that are anticipated to be ready to proceed before completion of the Environmental Impact Assessment Report, such as station construction, rail corridor expansion, utility relocation or bridge replacement or expansion, as defined in O. Reg. 341/20.

Early Works Reports will provide a description of the early works and alternatives considered, document local environmental conditions, and outline early works-specific environmental impacts, mitigation measures, monitoring activities, potentially required permits and approvals and other components.

Ontario Line early works are being advanced where the Project interfaces with other concurrently planned transit projects (i.e., GO Expansion) and where portions of the alignment run in parallel to the existing Lakeshore East and Lakeshore West GO rail corridors.

Advancing work in these areas provides planning, design and implementation efficiencies for the interfacing projects, and will facilitate timely implementation of the Ontario Line Project.

At this time, the following Ontario Line early works are being planned:

  • Exhibition Station
  • Lower Don Bridges
  • Lakeshore East Joint Corridor

Enabling early works proposed to begin in 2021 include:

  • Exhibition Station – an extension to the existing passenger tunnel; a temporary pedestrian bridge; a new north platform and accompanying shift of the northern two GO tracks; and, utility relocation and protection. Learn more.
  • Lower Don Bridges – two bridges added to either side of the existing rail bridge, with space for tracks going in both directions.
  • Lakeshore East Joint Corridor – rail corridor expansion between Eastern Avenue and Logan Avenue to accommodate four GO rail tracks and two Ontario Line tracks, including: grading; installation or upgrading of vegetated slopes or retaining walls and noise barriers next to the corridor, where appropriate; relocation or protection of utilities; and, construction of new Ontario Line bridges on each side of the existing Queen, Dundas and Logan bridges.
map of Ontario Line early works

Following finalization of the Environmental Conditions and Early Works Reports, a draft Environmental Impact Assessment Report will be made available for public review and comment. This report will include a final description of the Ontario Line Project, environmental impact evaluation results, mitigation measures, monitoring activities, potentially required permits and approvals and other components as outlined in O. Reg. 341/20.

Studies to support the Environmental Impact Assessment Report are currently underway. This Report is anticipated to be available for public review in early 2021.