Favorable California Supreme Court Decision for Product Manufacturers & Distributors: California High Court Adopts Sophisticated User Doctrine as Complete Defense in Product Liability Failure to Warn


In a change that will reshape the landscape of California product liability litigation, the California Supreme Court adopted the “sophisticated user” doctrine as a complete defense in actions premised on a defendant’s alleged failure to warn. Under the court’s decision in Johnson v. American Standard (April 3, 2008) ___Cal.4th ___ (S139184), manufacturers and distributors are relieved from

their general duty to warn sophisticated or particularly knowledgeable users about a product’s inherent dangers when those dangers should reasonably be known to that class of users by reason of the class’s specialized education or experience.

In the case that prompted this landmark ruling, plaintiff William Johnson, a certified heating, ventilation, and air conditioning technician, alleged he suffered injury from the inhalation of phosgene gas created when he brazed refrigerant lines on an air conditioning unit. Johnson sued

the manufacturer of the unit, American Standard, alleging it knew that phosgene gas would be created during brazing, but failed to provide an adequate warning regarding the risk.

Invoking the “sophisticated user” defense, American Standard moved for summary judgment. American Standard argued that it had no duty to warn because the risks associated with the creation of phosgene gas during brazing were widely known within the air conditioning maintenance and repair industry. The trial court granted summary judgment on this ground, which the Court of Appeal affirmed.

On review, the California Supreme Court officially adopted the sophisticated user doctrine as an affirmative defense in failure to warn cases, observing that the doctrine is a natural outgrowth of the widely recognized rule that there is no duty to warn of obvious dangers. Under the court’s holding, a manufacturer or distributor has no duty to warn members of a particular trade or profession about dangers that are obvious or generally known within that trade or profession.

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