Syllabus

NOTE: Where it is feasible, a syllabus (headnote) will be released, as is being done in connection with this case, at the time the opinion is issued. The syllabus constitutes no part of the opinion of the Court but has been prepared by the Reporter of Decisions for the convenience of the reader. See United States v. Detroit Timber & Lumber Co., 200 U. S. 321, 337.

SUPREME COURT OF THE UNITED STATES

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 sig- nificant damage to the vehicle. Glacier’s truck drivers are members of the International Brotherhood of Teamsters Local Union No. 174. Af- ter 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 directed drivers to ignore Glacier’s instructions to finish deliv- eries in progress. At least 16 drivers who had already set out for de- liveries returned with fully loaded trucks. By initiating emergency maneuvers to offload the concrete, Glacier prevented significant dam- age 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 conduct 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 federal law generally preempts state law when the two conflict, the NLRA preempts state law even when the two only arguably conflict. 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 en- 2 GLACIER NORTHWEST, INC. v. TEAMSTERS

Syllabus

gage in other concerted activities for the purpose of collective bargain- ing or other mutual aid or protection,” 29 U. S. C. §157—at least argu- ably 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 con- crete product because that loss was incidental to a strike arguably pro- tected by federal law.” 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. 6–12. (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 imminent danger due to the sudden cessation of work. Bethany Medi- cal Center, 328 N. L. R. B. 1094. Given this undisputed limitation on the right to strike, the Court concludes that the Union has not met its burden as the party asserting preemption to demonstrate that the NLRA arguab