A Massachusetts farmer owned a dump truck for hauling soil. One morning in April 2009, he was seen at his farm working on the truck. Later that day, he was found dead underneath it, with his clothing caught up in a spinning universal joint (U-joint) that was part of the mechanical system used to tilt the truck. The medical examiner identified the cause of death as accidental asphyxiation.As an executrix of his estate, his widow filed a Massachusetts wrongful death action. She sued, among others, Mack Trucks, which manufactured the original version of the truck, and Parker-Hannifin Corporation, which had acquired the assets of Dana Corporation. Dana manufactured a piece of equipment known as a “power take-off” (PTO), which was another part of the system used to tilt the dump body of the truck. In two separate summary judgment rulings, different superior court judges ruled in favor of each of these defendants. The Massachusetts Court of Appeals affirmed the judgments.
On appeal, the plaintiff did not argue that the incomplete vehicle that Mack Trucks sold, or the PTO that Dana sold, contained any design defect. Instead, the gravamen of her claims was that the manufacturers had a duty to warn installers and end users about the dangers posed by the use of unguarded auxiliary drive shafts and U-joints because such future uses were foreseeable. After all, she argued, the transmission of the truck was designed so that it could accept a PTO, and PTOs could be operated to power an auxiliary drive shaft. In fact, the plaintiff maintained that the foreseeability of the risks posed by exposed auxiliary drive shafts and U-joints was best demonstrated by the fact that Mack Trucks and Dana each provided some warning about them (warnings that the plaintiff claimed ultimately were inadequate). In the alternative, the plaintiff argued that even if the defendants did not face an independent legal duty to warn about such dangers, they voluntarily assumed such a duty when they provided their warnings about such uses.
The Massachusetts Supreme Judicial Court has endorsed the prevailing view that a supplier of a component part containing no latent defect has no duty to warn the subsequent assembler or its customers of any danger that may arise after the components are assembled. A component part manufacturer has no duty to provide a warning of a possible risk created solely by an act of another party that would not be associated with a foreseeable use or misuse of the manufacturer’s own product. This rule recognized by Massachusetts courts became known as “the component parts doctrine.”