Dan Himmelfarb

Dan has filed more than 200 merits and petition-stage briefs in the US Supreme Court, and scores of briefs in other federal and state appellate courts throughout the country. He has argued more than 50 cases in 12 different appellate courts, including 12 in the US Supreme Court, 6 in the DC Circuit and 14 in the Second Circuit.

Prior to joining Mayer Brown, Dan served for five years as an Assistant US Attorney in the Southern District of New York and then for five years as an Assistant to the US Solicitor General. He received the US Attorney General’s Distinguished Service Award. Dan also previously worked in private practice in New York. He had judicial clerkships with Judge J. Michael Luttig of the US Court of Appeals for the Fourth Circuit and Associate Justice Clarence Thomas of the US Supreme Court.

Clients Dan has served include Arkema Inc., CSX Transportation, Inc., and Lockheed Martin Corp.

Dan is a co-author of the tenth and eleventh editions of Supreme Court Practice, published by BNA/Bloomberg in 2013 and 2019. He is also a co-author of the first, second and third editions of Federal Appellate Practice, published by BNA/Bloomberg in 2008, 2013 and 2018.

• Collier v. CSX Transp., Inc., 673 F. App’x 192 (3d Cir. 2016) (briefed for appellee CSX): The Third Circuit enforced a railroad employee’s release of claims and rejected the employee’s contention that the release was void under Section 5 of the Federal Employers’ Liability Act.
• Lockheed Martin Corp. v. United States, 833 F.3d 225 (D.C. Cir. 2016) (briefed and argued for appellee Lockheed Martin): The DC Circuit held that it is not a prohibited “double recovery” for a contractor to recover under CERCLA and then credit back the government’s share of cleanup costs after having passed the costs along to the contractor’s customers as part of the price of goods and services.
• Fla. Dept. of Transp. v. Schwefringhaus, 188 So. 3d 840 (Fla. 2016) (briefed and argued for appellee CSX): Deciding issues certified to be of great public importance by an intermediate appellate court, the Florida Supreme Court unanimously held that sovereign immunity does not excuse the Florida Department of Transportation from complying with an indemnity provision in a contract with CSX and that the Department’s liability under the indemnity provision is not capped by a Florida statute limiting state agencies’ liability for tort claims.
• Rotech Healthcare Inc. v. United States, No. 15-5025 (Fed. Cir. 2016) (briefed for appellee Rotech): After briefing, the United States withdrew its appeal of a Court of Federal Claims decision holding that the Small Business Act’s “nonmanufacturer rule,” which requires small-business wholesalers and retailers to supply the products of small-business manufacturers, applies to a government contract for the rental of home healthcare equipment.
• Brown v. Lockheed Martin Corp., 814 F.3d 619 (2d Cir. 2016) (argued for appellee Lockheed Martin): In the first appellate decision to address the issue after the Supreme Court’s decision in Daimler AG v. Bauman, the Second Circuit held that Connecticut law does not subject a company to the general jurisdiction of Connecticut courts based solely on the company’s registration to do business in the state.
• United States v. Modanlo, No. 14-4044 (4th Cir. 2016) (briefed and argued for appellant Modanlo): After briefing and oral argument of an appeal challenging a conviction for violations of the Iran trade embargo, President Obama commuted Modanlo’s sentence and the appeal was dismissed.
• CSX Transp., Inc. v. Peirce, No. 13-2235 (4th Cir. 2014) (briefed and argued for appellee CSX): After briefing and oral argument, appellants, two lawyers and a doctor, withdrew their appeal of a jury verdict in favor of CSX finding that the lawyers and doctor violated the federal RICO statute and committed common-law fraud by manufacturing and filing fraudulent asbestos claims against CSX.
• New Era Group, Inc. v. EPA, No. 14-1054 (D.C. Cir. 2014) (briefed for intervenor Arkema): Taking the unusual step of summarily denying the petition for review, without merits briefing or oral argument, the DC Circuit held that EPA permissibly denied a petition for reconsideration of an agency rule that asserted claims that could have been raised earlier.
• Arkema Inc. v. EPA, No. 13-3292 (3d Cir. 2014) (briefed for petitioner Arkema): After Arkema filed its opening brief challenging EPA’s listing of two chemicals for testing for possible effects on the endocrine system, EPA confessed error and filed, and the Third Circuit granted, a motion for voluntary vacatur of the list insofar as it included those chemicals.
• Ray Haluch Gravel Co. v. Central Pension Fund, 571 U.S. 177 (2014) (briefed and argued for petitioners Ray Haluch Gravel Co. et al.): The US Supreme Court unanimously held that a decision leaving unresolved a request for contractual attorney’s fees is subject to immediate appeal.
• Honeywell Int'l, Inc. v. EPA, 705 F.3d 470 (D.C. Cir. 2013) (briefed and argued for intervenor Arkema): The DC Circuit rejected competitors' challenges to Arkema's transfers of allowances for the production of ozone-depleting refrigerants. The case was featured in The National Law Journal's 2013 "Appellate Hot List."  
• Johnson v. Arkema Inc., 685 F.3d 452 (5th Cir. 2012) (briefed and argued for appellee Arkema): In this toxic-tort case, the Fifth Circuit affirmed the exclusion of the plaintiff’s causation experts and affirmed the grant of summary judgment to Arkema with respect to the plaintiff’s alleged chronic injuries.
• CSX Transp., Inc. v. Gilkison, 406 F. App'x 723 (4th Cir. 2010) (briefed and argued for appellant CSX): The Fourth Circuit reinstated a suit, dismissed by the district court, alleging that lawyers and a doctor violated the federal RICO statute and committed common-law fraud by manufacturing and filing fraudulent asbestos claims against CSX.
• Nat’l Petrochemical & Refiners Ass’n v. EPA, 630 F.3d 145 (D.C. Cir. 2010) (argued for intervenor National Biodiesel Board): The DC Circuit rejected challenges to the EPA’s “RFS2” regulation, which requires that transportation fuel include certain percentages of renewable fuel.
• Arkema Inc. v. EPA, 618 F.3d 1 (D.C. Cir. 2010) (briefed and argued for petitioner Arkema): The DC Circuit vacated, as impermissibly retroactive, an EPA rule allocating allowances for the production of ozone-depleting refrigerants.  The case was featured in The National Law Journal's 2011 "Appellate Hot List."
• Kuzinski v. Schering Corp., 384 F. App’x 17 (2d Cir. 2010) (briefed and argued for appellant Schering): The Second Circuit held that pharmaceutical sales representatives are not exempt from the Fair Labor Standards Act’s overtime-pay requirements, a position that was rejected by the Supreme Court in a later case.
• Lyman v. CSX Transp., Inc., 364 F. App’x 699 (2d Cir. 2010) (briefed and argued for appellee CSX): The Second Circuit held that CSX was correctly granted summary judgment on the plaintiff’s claim of negligence under the Federal Employers’ Liability Act.
• Hensley v. CSX Transp., Inc., 310 S.W.3d 824 (Tenn. Ct. App. 2009) (briefed and argued for appellant CSX): On remand from the US Supreme Court, the Tennessee Court of Appeals held that the trial court’s failure to give an appropriate “fear of cancer” instruction was not harmless error and reversed a $5 million jury verdict.
• Borger v. CSX Transp., Inc., 571 F.3d 559 (6th Cir. 2009) (briefed and argued for appellee CSX): The Sixth Circuit held that CSX was correctly granted summary judgment on the plaintiff’s claim under the Federal Employers’ Liability Act that he had been negligently exposed to hydrochloric-acid fumes.
• CSX Transp., Inc. v. Hensley, 556 U.S. 838 (2009) (per curiam) (briefed for petitioner CSX): Taking the highly unusual step of summarily reversing the decision below, without merits briefing or oral argument, the US Supreme Court held that, when a plaintiff seeks damages for asbestosis-related “fear of cancer” under the Federal Employers’ Liability Act, the defendant is entitled to a jury instruction that the fear must be “genuine and serious.”  The case was featured in The National Law Journal’s 2010 “Appellate Hot List.”