Ontario Line

A new 15.6-km subway line in Toronto that will run from Exhibition Place, through downtown, all the way to the Eglinton Crosstown LRT at Don Mills Road.

Projects & Programs
Ontario Line
Resources
Environmental Impact Assessment Report

Environmental Impact Assessment Report

The Environmental Impact Assessment Report provides a description of local environmental conditions, potential impacts, proposed mitigation and monitoring measures, a record of consultation, and a description of future permits and approvals that may be required.

Read the full Environmental Impact Assessment Report

Read the Statement of Completion

Read the Notice of Final Publication

Read Appendix B – Part 1: Consultation and Correspondence Record

Read Appendix B – Part 2: Consultation and Correspondence Record

Read Appendix B – Part 3: Consultation and Correspondence Record

Read Appendix C – Ontario Line Profile Drawings

Explore each of the environmental assessment components and read about how we plan to address impacts below.

Natural environment

Potential effects and mitigation measures

Potential effects

Construction

Disturbance, displacement, or mortality of wildlife.
Removal of/damage to trees, terrestrial vegetation, and wildlife habitat.
Introduction or spread of invasive species.
Erosion and sedimentation.
Reduction in ecological function, habitat quality, and integrity.
Removal of/damage to aquatic/riparian vegetation and wetlands.
Potential for direct, in-water impacts to fish and fish habitat related to temporary crossing structures for the Don River crossings/bridges.
Construction may cause soil erosion and increased surface water/stormwater run-off resulting in changes to stormwater quality and quantity.

Operation

Operations may cause soil or water contamination as a result of spills (e.g., grease and/ or fuel) from equipment use during maintenance activities.
Operations may cause disturbance or displacement of wildlife during vegetation maintenance activities.

Mitigation measures

Construction

Vegetation removal will be reduced to the greatest extent possible and limited within the area affected by construction and maintenance activities.
Compensation for tree removals and vegetation will be undertaken in accordance with the Metrolinx Vegetation Guideline (2020) and principles of the Toronto and Region Conservation Authority Guideline for Determining Ecosystem Compensation (June 2018).
- Temporarily disturbed areas will be re-vegetated using non-invasive, preferably native plantings and/or seed mix.
Erosion and sediment control measures will be implemented.
A Spill Prevention and Response Plan will be developed for construction and operations.
All requirements of the Fisheries Act including those pertaining to in-water works will be met during construction.
Sensitive wildlife timing restrictions will be followed for construction activities (e.g., removal of vegetation outside of the breeding bird season).
Wildlife exclusion measures will be implemented as required to avoid destruction, injury or interference with wildlife species and their habitat.
All requirements of the Endangered Species Act and Species at Risk Act will be met.
Floodplain impact assessment will be conducted during detailed design following Toronto and Region Conservation Authority guidelines.
A Stormwater Management Plan will be developed prior to construction.

Operation

A Spill Prevention and Response Plan will be developed for operations.
Vegetation removal will be reduced to the extent possible and limited to the Metrolinx right-of-way.
Monitoring and management of trees/vegetation in the rail corridor right-of-way.
An Integrated Vegetation Management Plan will be developed.

Heritage

Archaeology

Socio-economic and land use characteristics

Air quality

Potential effects and mitigation measures

Potential effects

Construction

Increase in air pollution and odour because of construction vehicle emissions and increased traffic due to construction activities.
Increase in dust, silica and airborne particulate matter resulting from earthworks, material handling and transfer, demolition, and construction activities.
Construction activities could expose contaminated soils/ materials and/or result in the spreading of contaminated materials.
Greenhouse gas emissions are expected to increase temporarily due to construction activities, but a net overall decrease in Greenhouse gas emissions will occur as a result of the operation of the Project.

Operation

There is expected to be a net overall decrease of 14,000 tonnes of greenhouse gas emissions per year.
Operation of the maintenance and storage facility and maintenance staff may cause minor air quality impacts from work vehicle fuel combustion and maintenance activities.

Mitigation measures

Construction

Dust monitors will be used in some areas to monitor allowable dust levels and when mitigation measures will be required.
A detailed Construction Air Quality Management Plan will be developed and implemented to manage air quality throughout construction.
Dust suppressants such as water sprayers will be used, as required.
Low emission construction equipment will be used, wherever possible.
A Communications Protocol will be developed to encourage timely resolution of complaints.
Crews will reduce the amount of machines operating in one area at any given point where possible.
Visual and olfactory inspections will be conducted during excavation or for incoming loads to screen for odour, visible staining or debris per the Ministry of Environment, Conservation and Parks Management of Excess Soils, A Guide for Best Management Practices (2019).

Operation

A detailed Operations Air Quality Management Plan will be developed and implemented.
Emissions will be assessed and modelled following Ministry of Environment, Conservation and Parks guidance and will comply with applicable Ontario Regulation 419/05 standards.
To reduce emissions intensity at the maintenance and storage facility, select equipment with engines and propulsion systems that meet higher emission standards (i.e., Tier 4 rather than a lower tier) will be used.

Noise and vibration

Potential effects and mitigation measures

Potential effects - noise

Construction

Environmental noise may cause annoyance and disturb sleep.
Additional truck traffic accessing staging areas could cause sound level increases.

Operation

Environmental noise may cause disturbance and/or annoyance.
Airborne noise will result from the operations of the Project and may be a concern for noise sensitive areas.

Mitigtation measures - noise

Construction

Establishing and applying Project-specific construction noise criteria/exposure limits.
Keeping construction equipment in good working order and operate with effective muffling devices.
Use of localized noise barriers for specific equipment and operations.
Noise monitoring and regular reporting throughout the construction phase, as required.
- Site-specific mitigation will be determined prior to the start of construction based on selected means and methods.
Develop a communications protocol for providing advanced notice of construction work and addressing public complaints in a timely manner.

Operation

Noise barriers of varying heights are required in a number of locations along the rail alignment to mitigate train noise.
As part of the future detailed design of the stations, comfort ventilation systems should be selected to comply with a maximum sound level limit of 60 dBA at 1 metre from all mechanical louvers and rooftop HVAC equipment.
Excess noise sources at the station are to be fitted with mitigation as required to meet Ministry of Environment, Conservation and Parks Noise Pollution Control 300 criteria.
Outdoor audio paging system, transformers, and generators will be required to meet Ministry of Environment, Conservation and Parks Noise Pollution Control 300 noise limits at adjacent receptors, and the system will be designed to do so by limiting speaker volume and positioning speakers away from neighbouring residences.

The maintenance and storage facility doors will remain closed (a central colling system may be required in the garage area) and/or a sound-reducing vestibule will be constructed around the door openings.

Potential effects - vibration

Construction

Vibration from tunneling can cause annoyance, interfere with human activities, and interfere with vibration-sensitive equipment operations.
The highest levels of construction ground-borne vibration are expected to be associated with compaction with a vibration roller, truck activities in staging areas, and operation of the tunnel boring machine.
Without mitigation, vibration may cause damage to buildings, utilities, and other structures during construction.

Operation

Vibration levels are anticipated to be low and not cause structural damage.
Vibration impacts were predicted at seventy-one (71) representative points along the entire alignment, to inform development of site-specific mitigation measures.

Mitigation measures - vibration

Construction

Maintain the setback distances for construction equipment.
Site-specific mitigation will be determined prior to the start of construction based on selected means and methods.
Develop a communications protocol for providing advanced notice of construction work and addressing public complaints in a timely manner.
Vibration measurements will be assessed using mock-up construction activities prior to construction at certain receptor locations (i.e., St. Michael’s Hospital, Bell Media Headquarters, Four Seasons Centre for the Performing Arts).

Operation

Consider equipment with low vibration levels.
Site-specific mitigation will be determined prior to the start of operations based on selected means and methods
Develop a communications protocol for providing advance notice of construction work and addressing public complaints in a timely manner.

Traffic and transportation

Potential effects and mitigation measures

Potential effects

Construction

Construction will result in the need for temporary, partial, and full lane, street, sidewalk and trail closures.
Queen Street between Yonge Street and Victoria Street will be closed for approximately 6 months. Queen Street west of Victoria Street will be closed for the duration of the Queen Station construction.
Increase in construction vehicle traffic may cause impacts to traffic flow on the local road network.
Temporary, partial, or full closures of sidewalks, trails, pedestrian and cyclist pathways.
Construction may result in access restrictions to local bus routes, temporary changes in bus stop shelters/locations, and temporary disruptions to the existing rail corridor.

Operation

Traffic improvements are anticipated as a result of operations.
The connection between Banigan Drive and Thorncliffe Park Drive will be permanently closed.
The increased pedestrian demands generated in the vicinity of Ontario Line stations may coincide with increased delays and worsened pedestrian levels of service for existing pedestrian trips that are not taking the Ontario Line.

Mitigation measures

Construction

Develop and implement a Transit and Traffic Management Plan prior to construction in consultation with local transportation and transit authorities.
Issue notifications and advisory signage to alert traffic and transit users of any upcoming road closures and disruptions as required.
Ensure the appropriate signage and notifications are provided to safely direct pedestrians and cyclists around closed active and transit network sections.
Access to nearby lands and businesses will be maintained to the extent possible.

Operation

Signage and advance notification are recommended to notify station users of any detours.
Increase the surface transit stop area through either the removal or relocation of sidewalk furniture and increasing surface transit frequency/capacity should be considered, where feasible.

Soil and groundwater

Related Projects

Kitchener Line GO Expansion

We're transforming the Kitchener Line into a two-way, all-day rapid transit line.

PEELTORONTO REGIONGUELPH AND WELLINGTONHALTONWATERLOOGO EXPANSION

Yonge North Subway Extension

Extending the TTC’s Line 1 service north from Finch Station to Vaughan, Markham, and Richmond Hill.

YORKSUBWAYS

SSE Scarborough Centre Platform Rendering

Scarborough Subway Extension

Extending Line 2 subway service 7.8 km farther into the heart of Scarborough.

TORONTO REGIONSUBWAYS

Eglinton Crosstown West Extension

Extending the Eglinton Crosstown LRT 9.2 km farther west into Etobicoke and Mississauga.

TORONTO REGIONSUBWAYS

Eglinton Crosstown LRT

A midtown connection between east and west Toronto with 25 stations along a dedicated route.

TORONTO REGIONRAPID TRANSIT

Land Acknowledgement

Metrolinx acknowledges that we connect communities by building and operating transit within the traditional lands of the Anishinaabe, the Haudenosaunee and the Wendat peoples, for whom these lands continue to have great importance.
Treaties between First Nations and governments cover these lands, and the promises contained in these Treaties remain relevant to this day.
Metrolinx and its employees are committed to understanding the history of these lands and the continued impacts of colonization and take responsibility for actions to advance reconciliation.
Metrolinx will continue to seek the knowledge, expertise and experience of Indigenous partners and commits to doing business in a manner that is built on a foundation of trust, respect, and collaboration.