"Drivers reported for work and those with early runs had their trucks loaded with cement. At the appointed hour for the onset of the strike..."
"... the drivers drove their trucks back to the company’s headquarters and walked off the job. For those whose trucks had already been loaded with cement but who had not yet made deliveries, they left their trucks running so the cement wouldn’t instantly harden inside the trucks’ drums. The company, however, was unable to deliver the cement and some of it hardened, requiring it be destroyed and carted away. The strike lasted one week before the parties reached agreement on a new contract."
From "Cement-truck drivers went on strike/A lawsuit by their company may pave the way for restricting workers’ rights," the SCOTUSblog write-up of Glacier Northwest v. International Brotherhood of Teamsters, Local Union 174. Oral argument is this morning.
Glacier sued the Teamsters Union, which represents the drivers, for “tortious destruction” of the company’s property.... The Washington Supreme Court dismissed the case, finding that it wasn’t appropriate to apply state tort law to a labor dispute covered by a federal law, the National Labor Relations Act....
In San Diego Building Trades v. Garmon, the Supreme Court interpreted this preemptive effect broadly, holding that the NLRA precludes application of conflicting or even arguably conflicting state law in order to ensure that labor law applies uniformly to all workers, unions, and employers across the country.
The court has recognized only a narrow exception to the preemption doctrine. Specifically, the court has allowed application of state tort law only for torts “so deeply rooted in local feeling and responsibility that, in the absence of compelling congressional direction, we could not infer that Congress had deprived the States of the power to act.”
Glacier argues that "intentional property destruction" — sabotage — is a matter of "local feeling."
There's also an argument that if federal law does preempt state law, it's a taking within the meaning of the Fifth Amendment and the federal government owes just compensation. That's a constitutional question that can be avoided by interpreting the federal statute not to preempt the state law claim.
There is more complexity, explained at the link, but the bottom line, per SCOTUSblog, is:
The Supreme Court has long recognized how central the right to strike is in protecting workers’ bargaining power. If employers have more leeway to argue that a strike has caused economic damage for which the union can be held liable, that right will be weakened.