Dan Dunn

Dan Dunn

Partner, Denver

Email dan.dunn@​hoganlovells.com

Phone +1 303 454 2425

Fax +1 303 899 7333

Practice groupLitigation

Dan Dunn offers 38 years of experience and a clear understanding of his clients' business objectives to consistently deliver successful results. He has litigated, arbitrated, and tried a wide range of cases with a special emphasis on environmental disputes in the natural resources, energy, aerospace, and insurance sectors.

Dan is nationally recognized for using innovative case management techniques to achieve early dismissals, saving clients the enormous costs of prolonged litigation and eliminating the risk of adverse outcomes. He has served as lead counsel in a number of the country's highest profile environmental cases, including several bet-the-company mass tort actions, a derailment and massive chemical spill into the Upper Sacramento River, and a multi-billion dollar Superfund action involving the Rocky Mountain Arsenal. As a trusted advisor, he also regularly helps clients manage potential environmental liabilities arising out of major projects and transactions in the United States and abroad.

Dan's success goes beyond environmental litigation and counseling. Showing versatility, he has achieved positive results for clients in a wide variety of other cases. Among them are enforcement of anti-doping laws against a now-defrocked winner of the Tour de France, defeating gerrymandering and Voting Rights Act challenges to legislative reapportionment plans, and pro bono representation of abused children seeking to terminate their parents' rights. Dan's court experience includes appeals in the U.S. Supreme Court and seven different U.S. Courts of Appeals.

Litigation success does not always translate to business success for clients. Often an early favorable settlement is more valuable. Dan's priority at the outset of a dispute is to get a firm grip on the facts, the law, and the client's ultimate business objective. Armed with this information, and drawing upon his considerable trial experience, he is better able to accurately predict the likely litigated outcome, estimate the costs of prolonged litigation, and counsel clients on settlement options.

Awards and recognitions


Mass Tort Litigation/Class Actions
The Best Lawyers in America


Natural Resources & Environment (Colorado)
Chambers USA


Environment: Litigation
Legal 500 US

2006-2015, 2018

Environmental Litigation
Colorado Super Lawyers

A-V Preeminent Rated


Top Litigator
Law Week Colorado


Named "Colorado Lawyer of the Year" as part of team that obtained back-to-back arbitration awards before U.S. and international tribunals, on behalf of the U.S. Anti-Doping Agency, against Floyd Landis for doping in the Tour de France.
Law Week Colorado


"Hero of the Year," for pro bono representation of abused children
Rocky Mountain Children's Law Center

Education and admissions


J.D., Georgetown University Law Center, cum laude, 1980

B.A., University of Colorado, with distinction, 1976


Master, American Inns of Court, Rhone-Brackett Inn, 2006-2015

Member, Environmental Law and Litigation Sections, Colorado Bar Association

Member, Litigation, Tort Trial & Insurance Practice, and Environment, Energy, and Resources Sections, American Bar Association

Member, Board of Directors, Rocky Mountain Children's Law Center, 2003-2007

Bar admissions and qualifications


Court admissions

U.S. Supreme Court

Supreme Court of Colorado

Supreme Court of Nevada

U.S. Court of Appeals, 10th Circuit

U.S. Court of Appeals, 9th Circuit

U.S. Court of Appeals, 8th Circuit

U.S. Court of Appeals, 3rd Circuit

U.S. Court of Appeals, District of Columbia Circuit

U.S. Court of Appeals, Federal Circuit

U.S. District Court, Eastern District of Arkansas

U.S. District Court, Central District of California

U.S. District Court, Eastern District of California

U.S. District Court, District of Colorado

U.S. Court of Federal Claims

U.S. District Court, District of New Mexico

U.S. District Court, District of North Dakota

U.S. District Court, Western District of Oklahoma

U.S. District Court, Middle District of Pennsylvania

U.S. Tax Court

U.S. District Court, Southern District of Texas

U.S. District Court, District of Utah

U.S. District Court, Western District of Washington

U.S. District Court, District of Wyoming

Representative experience

On behalf of U.S. Anti-Doping Agency, stripped Floyd Landis of his Tour de France title for doping in back-to-back U.S. and international arbitrations.

Represented Southern Pacific in enforcement and toxic tort actions for derailment and spill of tank cars with pesticides into Upper Sacramento River.

Defeated putative class action seeking to stop Antero Resource's oil and gas development using hydraulic fracturing.

Defeated putative class action by oil and gas royalty owners alleging client unlawfully flared gas from wells in the Bakken Field in North Dakota.

Obtained summary judgment for client in US$130m mass tort case after evidentiary hearing and ruling that plaintiffs' expert opinions were inadmissible.

Obtained summary judgment in two mass radiation toxic tort suits in Colorado and New Mexico federal courts after securing orders requiring plaintiffs to make early disclosure of expert opinions.

Secured summary judgment dismissal of citizen suit claim against a BHP coal company under Endangered Species Act (ESA).

Defeated environmental groups' challenge in federal trial and appellate courts under NEPA and ESA to halt 100-turbine wind project in California.

Defeated environmental groups' challenge in federal district and appellate courts under NEPA and ESA to rescind right-of-way granted to Nevada Power.

Defended Voting Rights Act and gerrymandering challenges to redistricting plans for Colorado legislature following the 1990 and 2000 decennial censuses.

Represented Shell in litigation filed by U.S. Army and Colorado asserting billion dollar CERCLA claims for contamination at the Rocky Mountain Arsenal.

Obtained directed verdict following opening arguments in toxic tort claim against Shell for contamination at Rocky Mountain Arsenal.

Jury verdict for Ford Motor in suit against its dealer for breach of lease and petroleum contamination from non-compliant underground storage tanks.

Resolved government and private party CERCLA liability claims against scores of potentially responsible parties at dozens of sites across the country.

Presented oral argument or handled petitions to the U.S. Supreme Court; the U.S. Courts of Appeal for the 10th, 9th, 8th, 3rd, District of Columbia, and Federal Circuits; and the Supreme Courts of Colorado and Nevada.

Latest thinking and events

Published Works

Environmental Citizen Suits Under the Trump Administration: Key Concepts and Risk Management for Extractive Industries Rocky Mountain Mineral Law Foundation, 63rd Annual Institute, July 2017

Sponsorships and Speaking Engagements

CLE International - Environmental Regulation of Energy Development Conference

Published Works

Environmental Citizen Suits Against Natural Resource Companies Natural Resources and Environment (Vol. 12, No. 3)

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