Michael J. Mahoney


Michael Mahoney helps clients address complex environmental issues and manage matters relating to environmental compliance. He has extensive experience advising clients on the environmental aspects of corporate and real estate transactions, including identifying and allocating environmental risks, negotiating and drafting environmental provisions of transaction documents, and obtaining and reviewing environmental site assessments and other diligence materials. Well versed in environmental law and with a business-focused approach, Mike helps his clients foresee risks and evaluate the best paths to reach their objectives.

Mike routinely advises clients on environmental regulatory matters, including obtaining permits, ongoing compliance, auditing and compliance program development, responding to government information requests, investigations and enforcement actions, and citizen suit defense. He also assists clients with carbon offset transactions and counsels clients on carbon offset standards as well as environmental, social, and governance (ESG) issues more broadly, including ESG reporting and disclosure and corporate sustainability programs. 

Committed to pro bono work, Mike focuses his efforts on activities to enhance environmental and social governance in developing countries, including in-country work in Cambodia and Myanmar and desk-based work for projects in Afghanistan and Malawi. 



  • Advised investor in acquisition of portfolio of power plants, including negotiating environmental contractual terms, conducting environmental due diligence, and coordinating permit transfers.
  • Counseled property owners seeking regulatory closure following voluntary cleanup of ‎contaminated properties under the Washington Model Toxics Control Act.
  • Assisted industrial contractor with Clean Water Act citizen suit defense.
  • Advised operator of glass recycling facilities in response to California Department of Toxic Substances Control notice.

Memberships & Awards


  • American Bar Association’s Section of Environment, Energy, and Resources, Waste and Resource Recovery Committee, Articles Vice-Chair (2021 - present)
  • American Bar Association’s Section of Environment, Energy, and Resources, Environmental Transactions and Brownfields Committee, Membership Chair (2021 - present)‎
  • King County Bar Association, Environmental and Land Use Law Section, Member (2021 - present), Co-Chair (2023 - present)
  • Washington ‎State Bar, Environmental and Land Use Section, Member
  • California Lawyers Association, Environmental Law Section, Member

Resources & Ideas

Seminars & Speaking Engagements

“Environmental and Real Estate Transactional Role in Entitlements,” Permitting Strategies CLE, The Seminar Group, December 1, 2021

Making and Keeping Corporate Climate Commitments, Law360, Co-Author, August 11-12, 2020

Community Activities

Community Activities

  • Georgetown University and Georgetown University Law Center, Alumni Admissions Program Volunteer (2015 - present)
  • International Senior Lawyers Project, Pro Bono Volunteer (2016-present)
  • International Accountability Project, Pro Bono Volunteer (2020 -present)
  • Asian Research Institute for Environmental Law, Pro Bono Volunteer (2021-present)




Washington State Courts

United States District Court, District of Western Washington

California State Courts

Outside The Office