Gregory R. Tan

Gregory R. Tan


Federal Lands
Energy & Natural Resources

Gregory R. Tan’s practice focuses on litigation and counseling for clients in a variety of industries on complex environmental enforcement and regulatory matters. Greg represents clients in environmental enforcement actions brought by federal, state, and local agencies and helps clients navigate regulatory requirements, manage environmental risk, and obtain permits and approvals necessary to move forward with development projects, real estate transactions, and day-to-day business operations. His clients include energy companies, developers, railroads, retailers, and trade associations.

Greg has over 25 years of experience handling environmental enforcement matters both as a former agency enforcement attorney and on behalf of his clients in private practice. Greg has litigated and settled a wide variety of civil, criminal, and administrative enforcement actions and private party actions under the Clean Water Act (CWA), Clean Air Act (CAA), Resource Conservation and Recovery Act (RCRA), Comprehensive Environmental Response, Compensation and Liability Act (CERCLA), Emergency Planning and Community Right to Know Act (EPCRA), and other federal, state, and local laws.

Greg counsels clients on regulatory compliance arising under state and federal environmental statutes and rules, and local zoning and development codes. Greg also advises developers, investors, and lenders on the environmental aspects of real estate transactions, including environmental due diligence and negotiating environmental terms in deal documents.

  • J.D., Vermont Law School, 1998
    • Personal Note Editor, Vermont Law Review
  • M.C.P., Master of City Planning, Georgia Institute of Technology, 1995
  • B.A., Urban Studies & Planning, University of California at San Diego, 1992
Bar and Court Admissions
  • Colorado
  • U.S. Court of Appeals for the Ninth Circuit
  • U.S. Court of Appeals for the Tenth Circuit
  • U.S. District Court for the District of Colorado
  • U.S. District Court for the Northern District of Georgia
Awards & Accolades
  • Listed, Lawdragon 500, Leading U.S. Environmental & Energy Lawyers guide, 2021
  • Recipient, two U.S. Department of Justice Certificates of Commendation, for outstanding performance and invaluable assistance in support of DOJ’s Environment and Natural Resources Division on major CWA and CAA judicial settlements
  • Recipient, EPA National Awards, including two gold medals, a silver medal and two bronze medals, for contributions to enforcement matters

Our Location

1801 California Street, Suite 3400
Denver, Colorado 80202

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Phone 303.861.2828
Fax 303.861.4017

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