Diana Weir

Counsel

Toronto
DiWeir@blg.com
416.367.7881
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Diana specializes in environmental law, offering legal and strategic advice on environmental matters related to Ontario, federal and municipal legislation.

Her practice includes obtaining environmental permits and authorizations, ensuring environmental compliance and acting as counsel on environmental aspects of business, such as due diligence in mergers and acquisitions.

Diana also has notable experience in litigation, defending clients charged with environmental and regulatory offences and conducting appeals of remediation orders. She frequently represents clients in environmental litigation claims before Ontario courts.

Experience

  • Advising a leading oil company in multiparty contaminated lands litigation.
  • Assists clients appealing to the Ontario Land Tribunal in relation to Ministry of the Environment, Conservation and Parks Director’s Orders.
  • Advising Plaintiffs and Defendants in multiple contaminated lands actions, bringing successful summary judgment motions to have actions dismissed based on the expiry of limitation periods.

Beyond Our Walls

Professional Involvement

  • Chair, Environmental Law Section Executive Committee, Ontario Bar Association
  • Member, Canadian Bar Association
  • Steering Committee Member, Cambridge Forum on Environmental Law 2nd Generation

Community Involvement

  • Volunteer, Pro Bono Ontario Free Legal Advice Hotline
  • Volunteer, Centre 55 Community Centre

Awards & Recognition

  • Recognized in the 2025 edition of The Canadian Legal Lexpert® Directory (Environmental Law).

Bar Admission & Education

  • Ontario, 2014
  • Certificate in ESG, Climate Risk and the Law, Osgoode Hall Law School (York University), 2023
  • JD, Queen's University, 2013
  • BA (Honours) (Faculty of Arts & Science), Queen's University, 2010