Dennis Edward Mahony

A leading lawyer in his field, Dennis has specialized knowledge in environmental law. From regulatory compliance to courtroom advocacy, Dennis works closely with clients on bespoke tactics to mitigate risk and maximize opportunity in environmental matters impacting clients’ operations, projects and transactions.

Dennis is the head of Torys’ Environmental, Health and Safety Practice, the Co-Chair of the firm’s interdisciplinary Climate Change and Emissions Trading Practice, and certified by the Law Society of Ontario as a Specialist in Environmental Law.

Dennis provides comprehensive environmental, health and safety advice to a broad range of public- and private-sector clients, including public and private companies, federal government agencies, Crown corporations, provincial bodies and municipalities. The scope of his counsel covers virtually every industrial sector: transportation, utilities, non-renewable and renewable energy, pulp and paper, mining, chemicals and plastics, water and waste water treatment and disposal, manufacturing, financial institutions and real estate development.

On projects, Dennis works alongside developers, lenders, technical consultants, regulators and other project stakeholders to plan, develop, permit and defend complex projects, often through sensitive environmental habitats. He regularly advises from the project planning stage through the approval and construction stages and into operation. His broad advice to clients spans regulatory compliance, major and minor environmental assessment and other approvals, strategic stakeholder management, and litigation before environmental tribunals and courts. Over the past several years, Dennis and various Torys teams have successfully advised and defended more major projects than any other environmental team in the country.