Restatement, Section 402A(1)(a), limits liability to sellers “engaged in the business of selling such a product.” The rule is intended to apply to people and entities engaged in business, not to casual one-time sellers. The business need not be solely in the defective product; a movie theater that sells popcorn with a razor blade inside is no less liable than a grocery store that does so. But strict liability under this rule does not attach to a private individual who sells his own automobile. In this sense, Restatement, Section 402A, is analogous to the UCC’s limitation of the warranty of merchantability to the merchant.
The requirement that the defendant be in the business of selling gets to the rationale for the whole concept of strict products liability: businesses should shoulder the cost of injuries because they are in the best position to spread the risk and distribute the expense among the public. This same policy has been the rationale for holding bailors and lessors liable for defective equipment just as if they had been sellers. 1