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Paul Seby is a leading practitioner in the Rocky Mountain region, with nearly 25 years' experience analyzing a myriad of environmental issues. He counsels public and private clients in the energy, mining, manufacturing, and service industries on how to navigate and operate within the complex framework of state and federal environmental regulations and policies. Mr. Seby has vast experience prosecuting cases to enforce and overturn administrative agency regulations and decisions, and has defended clients in federal and state enforcement proceedings, in appearances before the U.S. Supreme Court, several U.S. Courts of Appeal, and the Colorado Supreme Court, among others. Bearing in mind that a successful outcome is often a combination of traditional and non-traditional legal strategy, Mr. Seby leverages his experience to negotiate with government agencies and adversary groups.

Whether a lending transaction, M&A transaction, or other business venture, clients across the country trust Mr. Seby to draw upon his deep understanding of how government programs and agencies function to identify existing and potential environmental pitfalls they may face in achieving their business goals. He efficiently and effectively guides his clients in developing practical, workable strategies to take on legal and business challenges, and has been recognized for his work by many leading legal publications.


  • Environmental litigation
  • Energy and regulatory compliance
  • Climate change
  • Governmental affairs and investigations



  • Adarand Constructors v. Pena Inc., 515 U.S. 200 (1995). Seminal U.S. Supreme Court case determining the constitutional standard of review required under the Fifth Amendment equal protection clause for federal government contracting programs.°
  • Colo. Mining Ass'n et al. v. Huber, 240 P.3d 453 (Colo. Ct. App. 2010); rev’d Huber v. Colo. Mining Ass'n, 624 P.3d 884 (Colo. 2010). Mining Association and individual taxpayers challenge asserted the Department of Revenue’s increase in the coal severance tax rate for extracted coal without voter approval amounted to a tax rate increase, in violation of the Colorado constitution.°
  • Citizens for Clean Air & Water In Pueblo & Southern Colorado v. Pueblo County Planning Commission, Case No. 01CA1603 (Colo. 2002). Represented a major industrial facility client who intervened in a special interest group challenge against Pueblo County’s issuance of a county land use permit. District Court and Court of Appeals upheld County’s issuance of the permit.°
  • Colo. Mining Ass'n v. Board of County Comm'rs of Summit County, 199 P.3d 718, (Colo. 2009). Lead counsel in challenge by Colorado Mining Association to invalidate County ordinance banning the use of modern mining practices on the basis the ordinance was preempted by the Colorado Mined Land Reclamation Act. Decision by Colorado Supreme Court established key natural resource preemption law in Colorado.°
  • Dacotah Chapter of Sierra Club and Dakota Resource Council v. Secretary of the Interior Ken Salazar, Case No. 1:12-CV-065 (D.N.D. May 30, 2012); Dakota Resource Council v. North Dakota Public Service Commission, Case No. 1:12-CV-064 (D.N.D. May 30, 2012). Lead counsel for the North Dakota Public Service Commission in defeating two actions brought against it by special interest groups seeking to strip the State of its regulatory authority under the Federal Surface Mining Control and Reclamation Act.°
  • Wild Earth Guardians v. Office of Surface Mining, USDC District of Colorado ( 1:13-CV-00518-RBJ). Negotiated a settlement of a remedy on behalf of a mining company intervener in an action by a special interest group seeking to invalidate mine plan modifications issued to it by the U.S. Office of Surface Mining.°
  • Western Organization of Resource Councils v. Jewell, USDC District of Columbia (1:14-CV-01993-RBW, 2015). Represented State of North Dakota in lawsuit brought by a special interest organization seeking to invalidate and enjoin federal coal leasing program. Court granted intervention and motion to dismiss the case.°
  • USOR PRP Group v. City of Pasadena, USDC Southern District of Texas (4:14- CV-02441, 2015). Represented a municipality in a major CERCLA/Superfund case.°
  • State of Wyoming v. Jewell, USDC District of WY (15-CV-0043-SWS). Represented the State of North Dakota in a federal court challenge to BLM’s hydraulic fracking regulations; obtained a judicial stay of BLM Rule.°
  • North Dakota et. al. v. EPA et. al., USDC District of ND (3:15-CV-59-RRE). Lead counsel for State of North Dakota in leading coalition of twelve states in obtaining a preliminary injunction against EPA’s and U.S. Army Corps of Engineers’ “Waters of the United States” rule.°
  • Cunningham and Sohocki v. Colorado Air Quality Control Commission (Colo. App. 1999) Case No. 98 CA1861. Counsel for coalition of electric utilities; intervened and defeated an action by special interest group challenging favorable rule making clarifications adopted by the Colorado Air Quality Control Commission.°
  • Am. Corn Growers Ass'n v. EPA, 291 F.3d 1 (D.C. Cir. 2002). Lead counsel in action by national associations before the U.S. Court of Appeals challenging EPA’s original Regional Haze Rules regulations that were found to be unlawful and were remanded to the agency.°
  • Citizens for Clean Air & Water In Pueblo and Southern Colorado v. Colo. Department of Public Health & Environment, Case No. 02CA0669 (Colo. 2003). Represented major industrial facility client in intervening in action by citizens group challenging issuance of PSD permit issued to client. District Court and Court of Appeals upheld PSD permit.°
  • Associated Governments of Northwest Colorado v. Colorado Public Utilities Commission, 275 P.3d 646 (Colo. 2012). Lead counsel in action before Colorado Supreme Court preserving action seeking judicial review of Colorado Public Utility Commission’s adoption of electric generation mandate.°
  • North Dakota v. EPA, 730 F.3d 750 (8th Cir. 2012). Lead counsel for State of North Dakota’s challenge of EPA’s refusal to consider voluntarily installed existing pollution control technology at coal-powered electric generating plants in its regional haze BART analysis disapproving the State’s SIP and implementing an FIP. Case also involved defense of State air quality plans against collateral challenge by special interest organizations.°
  • Nat'l Envtl. Dev. Association's Clean Air Project v. EPA, 686 F.3d 803 (D.C. Cir. 2012); cert. denied; ASARCO LLC v. EPA, 2013 U.S. LEXIS 975 (U.S. 2013). Represented coalition of states challenging EPA ambient standard for sulfur dioxide alleging the EPA’s proposed modeling monitoring implementation approach violated federal notice and comment rulemaking requirements.°
  • United States v. Minnkota Power Cooperative, Inc., 831 F. Supp. 2d 1109 (D.N.D. 2012). Lead counsel for State of North Dakota in defeating an EPA challenge seeking to overturn North Dakota’s Best Available Control Technology determination for a large coal-fueled electric utility. The Court dismissed EPA’s challenge and upheld the State’s determination.°
  • Multiple Colorado, Wyoming, Montana, New Mexico, and North Dakota air quality-related rulemaking proceedings representing regulated entities, associations, or state or legal government parties.°
  • Full suite of permits and governmental approvals for siting and construction of greenfield $250 million Portland cement manufacturing facility in southern Colorado.°
  • PSD permitting and compliance counseling and negotiations in Colorado, South Dakota, North Dakota, Wyoming, and New Mexico for coal and natural gas-fueled power generation facilities; coal and hard rock mines, and major manufacturing facilities.°
  • Due diligence and in numerous acquisition transactions, including review, risk analysis and management of environmental issues involving rail transfer, mines, manufacturing, and power generation facilities valued over several billion dollars.°

°The above representations were handled by Mr. Seby prior to his joining Greenberg Traurig, LLP.

Recognition & Leadership

  • Team Member, a Law360 “Environmental Practice Group of the Year, 2022
  • Listed, The Legal 500 United States, 2016, 2018-2020, and 2022-2023
    • Industry Focus > Environment: Litigation, "Other Key Lawyer," 2022-2023
  • Listed, Denver Business Journal, "Who's Who in Energy," 2016-2018
  • Listed, Law360, Environmental MVP, 2016
  • Listed, National Law Journal, Energy & Environmental Trailblazers, 2016
  • Listed, Law Week Colorado
    • "Barrister’s Best Environmental Lawyer," 2014
    • "Lawyer of the Year," 2014 and 2016
  • Listed, Super Lawyers magazine, Colorado Super Lawyers, 2015
  • Member, Denver Bar Association
  • Member, Colorado Bar Association


  • J.D., Northwestern School of Law at Lewis & Clark College, 1991
  • B.A., University of San Diego, 1988
  • Colorado
  • Supreme Court of the United States
  • Supreme Court of Colorado
  • U.S. Court of Appeals for the Eighth Circuit
  • 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