Strict liability is conditioned upon the product reaching the user without substantial change in the condition in which it is sold. Similarly, a manufacturer is not liable in negligence if an intervening alteration of the product was the superseding cause of a consumer's injuries. This rule has been expressed alternatively as one of duty and one of causation. First, a manufacturer is only required to design a product that is safe for its reasonably foreseeable uses. If that duty is met, the product is simply not defective. Second, if a consumer alters a product in a way that creates a defect, the consumer's conduct rather than the manufacturer's is the proximate cause of any ensuing accident. Under either rationale, a post-sale product alteration will defeat a design defect claim if that alteration leads directly to the plaintiff's injury.
Plaintiff consumer purchased defendant manufacturer's miter saw, removed the blade guards, and accidentally cut off part of his thumb and lacerated his leg while using the saw. Plaintiff sued defendant alleging the product was both defective and lacked warnings against its use without the guards. The district court dismissed the complaint on summary judgment.
Whether the product had adequate warnings against its use without the guards even if it contained no specific description of what harm might occur if misused.
The court determined that defendant provided adequate warnings against using the saw without the guards, and did not manufacture a defective product. The court cited seven warnings on the tool or in the operator's manual against using the saw without the guards. The court stated that under Maryland law, the warning need not contain a specific description of what harm might occur if a product was misused, and held that warnings describing serious injury were sufficient. The court also held that the fact that the saw blade came off its spindle after plaintiff removed the guards did not make it a defective product. The court held that plaintiff's injuries were the direct result of his alteration of the tool. The court stated that strict liability was conditioned upon the product reaching the user without substantial change in the condition in which it was sold, and that a manufacturer was not liable in negligence if an intervening alteration of the product was the superseding cause of injury.