A long-running fight over a residential building project in north Toronto has now landed at Queen’s Park as the province considers a special zoning order that could dramatically scale back (or perhaps even stop) the development in order to protect a neighbouring vaccine facility.
At issue is 1875 Steeles Ave W, an aging four-storey rental building just west of Sanofi Pasteur’s vaccine campus near Steeles Ave W and Dufferin St. The Sanofi campus is home to Canada’s largest biomanufacturing and R&D facility, and has operated near the proposed project area for more than 110 years. Developer Tenblock wants to demolish the 1970s complex and replace it with three connected towers, with the tallest rising to 39 storeys. The project would include replacement units for existing tenants and hundreds of new rental apartments, some of them designated as affordable, according to city planning documents.
Sanofi has been fighting the proposal for several years. The company argues that high-rise towers overlooking its facility could create security risks and interfere with its ability to operate and expand (for example, by having hundreds of new residents looking directly into the site from more than 30 storeys up).
In a November 2025 letter to Toronto city council, Sanofi wrote that “[t]he proposed addition of 960 new residences within 115 metres may compromise the viability of ongoing production and future expansion and development potential on our Sanofi Site”, and warned that the change would worsen existing noise conflicts. The company supports capping nearby buildings at about 10 storeys, noting that anything taller could undermine Canada’s “health security posture.”
Toronto’s planning staff actually recommended approving Tenblock’s plan in June 2024, finding that the development met provincial and city growth policies. Council later voted to refuse the rezoning (Tenblock is appealing to the province’s land tribunal).
The province is now weighing a much stronger move: The Minister of Economic Development has asked for a Minister’s Zoning Order (MZO) that would cap all buildings at 33 metres (so, about 10 storeys) at the 1875 Steeles site “to safeguard the continued operational viability of Sanofi Pasteur Limited’s (Sanofi) manufacturing facilities and headquarters at 1755 Steeles Avenue West.”
As per a recent CBC report, if the MZO is approved, it would effectively kill Tenblock’s current project and reduce how much housing can be built there. Still, last week, Toronto City Council voted to endorse the proposed order.
As of publication, the province hasn’t yet made a final decision on whether to sign the zoning order.
