Volume 598 U. S. Part 2 Pages 771–815

OFFICIAL REPORTS OF

THE SUPREME COURT June 1, 2023

Page Proof Pending Publication

REBECCA A. WOMELDORF reporter of decisions

NOTICE: This preliminary print is subject to formal revision before the bound volume is published. Users are requested to notify the Reporter of Decisions, Supreme Court of the United States, Washington, D.C. 20543, pio@supremecourt.gov, of any typographical or other formal errors. OCTOBER TERM, 2022 771

Syllabus

GLACIER NORTHWEST, INC., dba CALPORTLAND v. INTERNATIONAL BROTHERHOOD OF TEAMSTERS LOCAL UNION NO. 174 certiorari to the supreme court of washington No. 21–1449. Argued January 10, 2023—Decided June 1, 2023 Glacier Northwest delivers concrete to customers in Washington State using ready-mix trucks with rotating drums that prevent the concrete from hardening during transit. Concrete is highly perishable, and even concrete in a rotating drum will eventually harden, causing signifcant damage to the vehicle. Glacier's truck drivers are members of the In- ternational Brotherhood of Teamsters Local Union No. 174. After a collective-bargaining agreement between Glacier and the Union expired, the Union called for a work stoppage on a morning it knew the company was in the midst of mixing substantial amounts of concrete, loading batches into ready-mix trucks, and making deliveries. The Union di- rected drivers to ignore Glacier's instructions to fnish deliveries in progress. At least 16 drivers who had already set out for deliveries Page Proof Pending Publication returned with fully loaded trucks. By initiating emergency maneuvers to offoad the concrete, Glacier prevented signifcant damage to its trucks, but all the concrete mixed that day hardened and became useless. Glacier sued the Union for damages in state court, claiming that the Union intentionally destroyed the company's concrete and that this con- duct amounted to common-law conversion and trespass to chattels. The Union moved to dismiss Glacier's tort claims on the ground that the National Labor Relations Act (NLRA) preempted them. While a fed- eral law generally preempts state law when the two confict, the NLRA preempts state law even when the two only arguably confict. San Diego Building Trades Council v. Garmon, 359 U. S. 236, 245. In the Union's view, the NLRA—which protects employees' rights “to self- organization, to form, join, or assist labor organizations, . . . and to engage in other concerted activities for the purpose of collective bar- gaining or other mutual aid or protection,” 29 U. S. C. § 157—at least arguably protected the drivers' conduct, so the State lacked the power to hold the Union accountable for any of the strike's consequences. The Washington Supreme Court agreed with the Union, reasoning that “the NLRA preempts Glacier's tort claims related to the loss of its concrete product because that loss was incidental to a strike arguably protected by federal law.” 772 GLACIER NORTHWEST, INC. v. TEAMSTERS

Syllabus Held: The NLRA did not preempt Glacier's tort claims alleging that the Union intentionally destroyed the company's property during a labor dispute. Pp. 779–785. (a) The parties agree that the NLRA protects the right to strike but that this right is not absolute. The National Labor Relations Board has long taken the position—which the parties accept—that the NLRA does not shield strikers who fail to take “reasonable precautions” to protect their employer's property from foreseeable, aggravated, and im- minent danger due to the sudden cessation of work. Bethany Medical Center, 328 N.