Profile
Matthew K. Tieslau advises public and private clients across the Rocky Mountain Region on complex environmental and regulatory matters. His practice spans both federal and state environmental regulatory compliance, enforcement actions and litigation, federal rulemaking advocacy, permitting, environmental audits, environmental due diligence for real estate transactions, brownfield developments, water law, and liquor licensing. His clients have included state and local governments, industrial manufacturers, oil and gas operators, mines, local property owners, and ranchers.
Matt’s approach to environmental regulatory issues is a comprehensive strategy focused on seeking to ensure that complex regulatory compliance matters do not impair his clients’ mission and day-to-day operations – staying ahead of compliance obligations to ensure that business can continue as usual. His experience also includes significant state and federal rulemaking advocacy, helping clients participate in rulemaking and policy development to pursue practical, reasonable, and achievable policy.
Matt has substantial experience navigating complex compliance issues under the Clean Water Act (CWA), Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA), Endangered Species Act (ESA), Energy Policy and Conservation Act (EPCA), Federal Land Policy and Management Act (FLPAM), Mineral Leasing Act (MLA), the National Environmental Policy Act (NEPA), and the Resource Conservation and Recovery Act (RCRA). He also advises on compliance and implementation matters related to building energy-use regulations in Colorado including the City and County of Denver’s Energize Denver regulation and the statewide Regulation 28 building performance standards.
Matt advises on water law matters related to water applications covering senior and junior rights, as well as exchanges and expansions, historical use quantification, and issues of state versus federal law. He also provides counsel on remediation and other water quality issues.
Matt also works on due diligence for the purchase and sale of manufacturers and retailers with liquor licenses, including national manufacturer mergers. He advises manufacturers, distributors, and food and beverage clients on local, state, and federal liquor licensing requirements, ongoing compliance, and day-to-day operations.
Concentrations
- Environmental and regulatory compliance
- Environmental auditing
- Environmental transactional due diligence
- State and federal environmental rulemakings
- Building Energy Codes and Building Performance Standards
- National Environmental Policy Act challenges
- Federal Tort Claim Act litigation
- Climate change
- Water rights transactions and litigation
- Mining
- Right-of-access
- Election law
- Liquor Licensing
Capabilities
Experience
- Representation of building associations in building performance rulemakings and Energy Policy and Conservation Act litigation in Colorado.
- Representation of governmental and private associations in policy and rulemaking development proceedings in both state and federal forums.
- Representation of non-profit organization in NEPA challenge to a U.S. National Park Service management decision in Puerto Rico.
- Oversight of confidential energy audits for compliance with building performance and green energy code regulations.
- Due diligence representation for various real estate transactions in Colorado, including stadium development projects.
- Representation of oil and gas operators and industry associations in Environmental Protection Agency and Bureau of Land Management regulatory rulemakings (including methane rulemakings) and federal litigation.
- Representation of industry clients in Environmental Protection Agency and Colorado Department of Public Health and Environment enforcement proceedings and consent decree negotiations.
- Represented industry clients in Colorado Energy and Carbon Management Commission (f/k/a Colorado Oil and Gas Conservation Commission) enforcement actions and settlement negotiations.
- Representation of industry associations in low and zero emission vehicle rulemakings in Colorado.
- Representation of oil and gas interests in Colorado Supreme Court case determining the statutory authority of the Colorado Air Quality Control Commission to issue oil and gas drilling permits under the Colorado Oil and Gas Conservation Act.
- Representation of parties regarding CERCLA, CWA, and RCRA compliance issues.
- Part of legal team for the State of North Dakota in Federal Tort Claims Act case regarding claims related to the Dakota Access Pipeline Protests, with eventual trial judgment obtained for the State of $27,854,867.30.
- Represented Colorado municipalities in the ongoing development and protection of existing water rights.
- Counsel for the City of Aurora in consent decree negotiations with the Colorado Office of the Attorney General relating to use of force, training, and chemical sedation policies by police and first responders.
- Counsel for the City of Aurora in negotiations with local firefighters’ union.
- Multiple party representations in Colorado Air Quality Control Commission rulemaking proceedings.
- Representation of Transportation Network Companies in Colorado Public Utilities Commission rulemakings and petitions.
- Representation of rideshare company in local procurement award negotiations.
- Representation of apartment amenity providers in fire code enforcement and compliance negotiations.
- Representation of parties in water applications covering senior and junior rights.
- Advised on Clean Water Act compliance obligations for industrial operations.
- Advised on the permitting for municipal wastewater management programs.
- Representation of multiple Colorado municipalities in the ongoing development and protection of existing water rights.
- Conducted due diligence for an international buyer in the purchase of multi-state brewery assets.
- Conducted due diligence for the sale of Colorado distillery assets.
- Advised on day-to-day regulatory compliance obligations, permitting requirements, and contract review for manufacturers and retail businesses.
Recognition & Leadership
- Listed, The Best Lawyers in America
- "Ones to Watch," Litigation - Environmental, 2023-2025
- "Ones to Watch," Natural Resources Law, 2023-2025
- "Ones to Watch," Environmental Law, 2024-2025
- Listed, The Legal 500 United States, Dispute Resolution > Product Liability, Mass Tort and Class Action - Defense - Toxic Tort, 2024
- Listed, Super Lawyers magazine, Colorado Super Lawyers, "Rising Stars," 2023-2024
- Team Member, a Law360 “Environmental Practice Group of the Year,” 2022
- Member, Colorado Bar Association
- Member, Environmental Law Section
- Member, Natural Resources & Energy Law Section
- Member, Water Law Section
- Member, Brewers Association
- Member, Faculty of Federal Advocates
Credentials
-
J.D., University of Colorado Law School
- Managing Editor, Colorado Natural Resources, Energy, & Environmental Law Review
-
B.S., Environmental Health, University of Georgia College of Public Health
- Member, Epsilon Nu Eta Environmental Health Honor Society
- Colorado
- Supreme Court of the United States