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Cotter Corporation, et al. v. Nikki Steiner Mazzocchio, et al.

Paid petition · United States Court of Appeals for the Eighth Circuit, No. 23-3709 · judgment October 30, 2024


Certiorari denied · May 18, 2026
Pre-decision estimate: 5% cert probability (95% interval 3%–9%)

Before the decision, modestly above the 4.1% base rate. The model weighted this up for counsel who has won certiorari before, an Eighth Circuit decision below, and a business petitioner.

Question presented

Under the Atomic Energy Act (AEA), private persons may possess, use, and dispose of specific nuclear materials only if authorized by federal statute or regulation. Handlers of these nuclear materials must comply with comprehensive safety regulations, including federal limits on the radioactive material they may release and the levels of radiation to which they may expose the public. For decades, these federal requirements have been understood to preempt state regulation of nuclear safety. See Pacific Gas & Elec. Co. v. State Energy Res. Conservation & Dev. Comm’n, 461 U.S. 190, 212 (1983). As amended by the Price-Anderson Act (PAA), the AEA also provides a federal cause of action for “public liability action[s],” including torts arising out of a statutorily-defined “nuclear incident.” 42 U.S.C. § 2014(ii). Because of federal field preemption, the federal courts of appeals have long uniformly held that federal nuclear safety regulations provide the standard of care in such actions. In the decision below, however, the Eighth Circuit created a circuit split, expressly rejecting the other circuits’ view and holding that state standards of care, as determined by local juries, serve as the standard of liability in actions under the PAA. The question presented is: Whether federal nuclear safety regulations preempt state tort standards of care in public liability actions. (I)

Counsel of record

For petitioner
Lisa Schiavo Blatt
Williams & Connolly LLP

For respondent
Barry James Cooper Jr.
Cooper Law Firm

Case

Conference history
Distributed for 3 conferences

Amicus briefs
2 cert-stage

Proceedings

  1. May 18 2026
    Petition DENIED.
  2. Apr 28 2026
    DISTRIBUTED for Conference of 5/14/2026.
  3. Apr 28 2026
    Supplemental brief of petitioners Cotter Corporation, et al. filed. (Distributed)
  4. Apr 28 2026
    Supplemental brief of respondents Nikki Steiner Mazzocchio, et al. filed. (Distributed)
  5. Apr 09 2026
    Brief amicus curiae of United States filed.
  6. Oct 06 2025
    The Solicitor General is invited to file a brief in this case expressing the views of the United States.
  7. Jul 16 2025
    DISTRIBUTED for Conference of 9/29/2025.
  8. Jul 16 2025
    Reply of petitioners Cotter Corporation, et al. filed. (Distributed)
  9. Jun 26 2025
    Brief of respondents Nikki Steiner Mazzocchio, et al. in opposition filed.
  10. May 16 2025
    Motion to extend the time to file a response is granted and the time is extended to and including June 26, 2025.
  11. May 14 2025
    Motion to extend the time to file a response from May 27, 2025 to June 26, 2025, submitted to The Clerk.
  12. Apr 25 2025
    Response Requested. (Due May 27, 2025)
  13. Apr 23 2025
    DISTRIBUTED for Conference of 5/15/2025.
  14. Apr 21 2025
    Brief amici curiae of Nuclear Energy Institute, Inc., et al. filed. (Distributed)
  15. Apr 17 2025
    Waiver of right of respondent Nikki Steiner Mazzocchio, et al. to respond filed.
  16. Mar 10 2025
    Petition for a writ of certiorari filed. (Response due April 21, 2025)