Toronto Hydro-Electric System Limited - Environmental Compliance Approval (sewage)

A new Environmental Compliance Approval Number 5444-DVQGGG was issued to Toronto Hydro-Electric System Limited on July 8, 2026 for sewage works consisting of a new spill containment system at the existing Hartsdale municipal substation located at 191 The Westway in the City of Toronto.

It was the opinion of the director that posting the proposed instrument for public comments would have resulted in danger to the health or safety of any person whose property is serviced by the local electrical grid, and injury or damage or serious risk of injury or damage to property, as outlined below:

• hartsdale MS supplies a few thousand residents in the Etobicoke area
• hartsdale MS at the time of the sewage works application was placed out of service for transformer replacement, requiring the load to be picked up by other neighbouring stations
• if equipment in one of the neighbouring stations were to be damaged due to added stress on the grid, this could lead to power outages especially during summer peak loading, which represents a danger to the health and safety of residents

Environmental Bill of Right (EBR) posting was not required because construction of the proposed sewage works is necessary to allow Toronto Hydro-Electric System Limited to proceed with the transformer replacement as soon as possible.

Details of issued Environmental Compliance Approval

The ministry has issued a new Environmental Compliance Approval to Toronto Hydro-Electric System Limited for sewage works consisting of a new spill containment system at the existing Hartsdale municipal substation located at 191 The Westway in the City of Toronto.

The proposed work consists of an individual passive oil containment pit for the transformer having a total design containment volume capacity of 12,821 litres. The pit liners will be comprised of passive materials with containment system designed to allow rainwater to filter through the liner materials but become impermeable when in contact with oil. A sub drainage system will be provided below the containment system to prevent water from accumulating in the pit and potentially reducing the available storage capacity.

The oil containment system will provide safeguards to the surrounding environment by retaining oil and contaminated water that may leak or spill as a result of a catastrophic failure in the electrical equipment. The discharge pump will be equipped with an oil-sensing device and discharge to a rip-rap surface outlet on the station property.