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Environmental Assessment and Compliance

Read About the Our Efforts to Ensure that Subway Construction Meets Environmental Standards

Here’s what Toronto-York Spadina Subway Extension is doing to meet Environmental Commitments.

Two Environmental Assessments were prepared on the Toronto-York Spadina Subway Extension TYSSE Project. A Toronto Environmental Assessment addresses four stations and the tunnel alignment from the Downsview Station to Steeles Avenue (approved by the Minister of the Environment, October 18, 2006 (received March 23, 2007). A York Region Environmental Assessment  (approved by the Minister of the Environment November 29, 2009) and a follow-on Conditions of Approval Report (approved by the Ministry of the Environment April 4, 2008) addresses two stations and the tunnel alignment from Steeles Avenue north to the Vaughan Metropolitan Centre area. Links to the original Environmental Assessment/Conditions of Approval reports are found below.

Click on the following link to access the Toronto-York Spadina Subway Extension Environmental Assessment and the York Region Conditions of Approval report.

Environmental Assessment of Detailed Design Changes

During detailed design changes to the alignment have been evaluated with two Environmental Assessment Amendments and two Effects Reports. The Ministry of the Environment has reviewed and accepted all of the reports as fulfilling the necessary amending requirements of the original Environmental Assessments.

Change in Tunnel Construction Method's at Downsview Park Station Area

Toronto Environmental Assessment Alignment changes are detailed in the report titled:

Change in Subway Tunnel Construction Methods at Sheppard West Station Area (July 12, 2010)

MOE Letter of Acknowledgment - Change - Downsview Park Station PDF file

 Change in Train Storage Location and Construction Methods for the Tunnels in Keele Street

Toronto-York Spadina Subway Extension in consultation with the Ministry of the Environment has decided not to proceed with a full Amendment to the approved Environmental Assessment for these changes, due to the absence of a change in effects on the environment from that found in the original Environmental Assessment. The report documents the changes included and the resulting effects. Report is titled:

Change in Train Storage Location and Construction Methods for the Tunnels in Keele Street (September 14, 2010)*

MOE Acknowledgement - Train Storage - Keele Street PDF file

York Region Environmental Assessment Changes documented in the report titled:

Tower 158 Avoidance EA Amendment (March 10, 2010)*

MOE Approval Letter Tower 158 EA Amendment PDF file

Changes in Subway Tunnel and Vaughan Metropolitan Centre Station Alignment Report*

MOE Acknowledgement - Vaughan Corporate Centre - Tunnel Alignment PDF file



Reports: Note that copies of all of the reports are available through the project office 416-397-8539 or email: and have been placed in the appropriate municipal clerk’s office and at the Ministry of the Environment.

Bus Route Changes


Review the new changes to bus routes in the area to connect to the new subway extension.

Read about it here!

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