Diana Weir

Of Counsel
Norton Rose Fulbright Canada LLP

Diana Weir

Diana Weir


Related services and key industries


Diana Weir has extensive experience in environmental law.  She provides legal and strategic advice on environmental matters concerning Ontario, federal and municipal legislation. She also advises clients on obtaining environmental permits and authorizations and verifies environmental compliance in their operations. Diana advises on environmental law aspects of business transactions, including due diligence reviews to assess environmental risks and compliance in connection with mergers and acquisitions as well as representation and warranty insurance in transactions.  

Diana advises clients on matters of contaminated lands, waste and hazardous materials management and, more generally, the release of contaminants, storage of petroleum products, wastewater management and air emissions.

Diana is also an experienced litigator, defending clients charged with environmental and regulatory offences under federal and provincial legislation, conducting appeals of remediation orders to the Ontario Land Tribunal (formerly the Environmental Review Tribunal), and defending and prosecuting environmental litigation claims by landlords, tenants and property owners before the Ontario courts.

Professional experience

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J.D., Queen's University, 2013
B.A. (Hons.), Queen's University, 2010 
  • Ontario 2014

Diana has advised or represented:


  • Multiple purchasers and vendors of industrial, commercial and residential properties on environmental due diligence, including, reviewing environmental reports and operational documents, providing advice on existing and potential liabilities and negotiating sale agreements

  • Environmental due diligence and transfer of environmental permits in merger and acquisition files

  • Leading providers of representation and warranty insurance with respect to the adequacy of environmental diligence to assess exposure

Compliance and Approval Issues

  • Clients seeking environmental compliance approvals

  • Clients in relation to compliance with, and permitting, under, Part V of the Environmental Protection Act (Ontario) and Regulation 347 relating to waste issues

  • Clients in relation to changes to extender producer responsibility legislation

  • Clients on reporting obligations in relation to environmental incidents (findings of historic contamination, finding of groundwater migration across property boundary, discharges to air, surface and groundwater)


  • Clients appealing to the Ontario Land Tribunal in relation to Ministry of the Environment, Conservation and Parks director's orders requiring remediation

  • Clients in the aggregates and chemical manufacturing industries charged with a variety of offences under the Environmental Protection Act and Ontario Water Resources Act

  • Both plaintiffs and defendants in multiple contaminated lands actions

  • "Environmental Due Diligence," Ontario Bar Association Mastering Due Diligence Program, September 28, 2021
  • Canadian Bar Association
  • Ontario Bar Association
  • The Law Society of Ontario
  • The Advocates' Society​
  • Newsletter editor, Environmental Law Section Executive Committee, Ontario Bar Association 
  • English