Opinion
This appeal presents the perplexing question whether liability for failure to warn of dangerous properties of a product is measured by the doctrine of strict liability in its generally understood sense or, alternatively, by traditional negligence concepts imposing a duty of-care requiring warning of danger only when there is actual or constructive knowledge of the danger.
The complaint for damages in this product liability action is framed upon four theories of substantive liability: negligence, express warranty, implied warranty and strict liability. At the conclusion of his case, and without moving to amend his complaint, plaintiff (appellant herein) requested that the trial court limit jury consideration of the case to the theory of strict liability in order to obviate defense reliance on contributory negligence. Ultimately the trial court instructed on strict liability for injury from products defective in manufacture or design but refused plaintiff’s proffered instruction that failure to warn of dangerous propensities likewise rendered a product defective. 1 Instead, the trial *70 court instructed on failure to warn only in the context of negligence. The jury was instructed that contributory negligence is not a defense to a cause of action in strict liability but that a plaintiff’s contributory negligence bars recovery for a defendant’s negligence.
Plaintiff contends the trial court’s instructional choices created error compelling reversal. For the reasons which follow we have determined that the jury should have been instructed on the theory of failure to warn in the context of strict liability in tort. The omission so to instruct was prejudicial to plaintiff’s case and requires reversal.
Plaintiff, Thomas Midgley, was 13 years old when he purchased from defendant Kresge a refracting telescope manufactured in Japan. When purchased the telescope was dismantled, its components in a cardboard box accompanied by a booklet of instructions on assembly, use and maintenance. The box bore the legend “Manufactured in Japan for S. S. Kresge Company . . . .” The telescope itself bore a label “K-Mart” accompanied by the phrase “Quality Guaranteed.” Kresge, owner of K-Mart Discount Stores, the retailer, was the only named defendant. The Japanese manufacturer was not a party.
Among the components of the telescope, is a sun filter consisting of a dark lens labeled “Sun.” The only instructions or warnings received by plaintiff relative to use of the telescope to view the sun are contained in the instruction booklet which provides: “Sun and moon glasses are deposited in the eyepieces cases; screwed into the eyepiece bottom. Be sure to use sun glass for solar observation and moon glass for moon observation. Caution: Please refrain from looking up the sun [sic] without attaching the sun glass. Also the sun should not be seen through the finderscope.” The instruction book contains no diagramatic or pictorial illustrations of the proper installation of the sun filter. Upon reading the warning, plaintiff knew he should view the sun only through the sun filter. He also knew before purchasing the telescope that it was dangerous to look at the sun with the naked eye.
The telescope eyepiece consists of a hollow cylinder approximately three-quarters inch in length, one inch in diameter and open on each end. Screw threads on the inner aspect of each end are of identical size. The eyepiece lens, of clear glass, can be screwed into either end of the cyUnder as may be the sun filter. When so joined together, the circumferences of the sun filter and the cylinder are flush. The eyepiece lens, however, is flanged so that when joined to the cylinder the flange projects beyond the circumference of the cylinder.
*71 In the first two months that he had the telescope, plaintiff used it to view the sun 15 to 20 times, always through the sun filter. In preparing to do so, plaintiff would remove the eyepiece lens and replace it with the sun filter. Properly assembled for sun viewing, the eyepiece lens should remain in place and the sun filter be screwed into the opposite or bottom end of the cylinder. When properly assembled the system is safe for sun viewing. As assembled by plaintiff, however, harmful sunlight could leak around the sun filter into the eye of the viewer. Plaintiff’s evidence, including expert testimony, tended to show that in so using the telescope he sustained a solar burn on the retina of his eye, irreparably impairing his vision.
I.
A retailer engaged in the business of distributing goods to the public is strictly liable in tort for personal injuries caused by defects in the products it sells.
(Vandermark
v.
Ford Motor Co.
(1964)
Citing Restatement, section 402A, California courts have held that a product faultlessly made may nevertheless be deemed defective within the general strict liability rule if it is unreasonably dangerous to place the product in the hands of a' user without adequate warning.
(Canifax
v.
Hercules Powder Co.
(1965)
*73
A serious question has arisen whether the existence of a product defect may in any way be conditioned upon the satisfaction of criteria derived from the substantive law of negligence. After the trial of this case, our Supreme Court rejected the Restatement requirement that a product defect must be shown to be “unreasonably dangerous” to the user or consumer
(Cronin
v.
J. B. E. Olson Corp.
(1972)
As we recognized in
Oakes
v.
E. I. Du Pont de Nemours & Co., Inc., supra,
the prerequisite of actual or constructive knowledge of product dangers as a limitation upon duty to warn thereof engrafts concepts of substantive negligence law onto the element of defect in cases of strict liability for failure to warn.
Oakes
was a pleading case. The complaint alleged that plaintiff contracted a severe systemic skin condition from allergic reaction to chemical ingredients in defendant’s weed killer; that substantial numbers of people are allergic to these chemicals; and that defendants failed to give adequate warning thereof. Demurrer to the complaint was sustained because the complaint did not allege that defendants knew or should have known of this effect of its product on allergic people. We affirmed the ensuing judgment of dismissal on the ground that defendants had no obligation “to warn the user of unknown and unknowable allergies, sensitivities and idiosyncracies” (
We are not called upon to determine in this opinion the extent, if any, to which the Oakes holding has been eroded by Cronin. It is sufficient for present purposes to point out that Oakes does not control the instant case because it is factually dissimilar. In the Oakes case, the danger posed by defendants’ product was a function of an idiosyncratic physiological reaction shared by only a limited number who might use the product. To *74 the extent that there remains a valid distinction in the law of strict liability for failure to warn between “known” and “unknowable” dangers, the problems noted in the Oakes case survive the re-formulation of strict liability law announced in the Cronin decision.
By contrast, the defendant herein marketed a technically complex product intended for use by technically unsophisticated consumers, to be assembled and used by them in accordance with instructions prepared and supplied by the technically knowledgeable supplier. Failure to assemble or use the product in accordance with these directions may well cause physical injury and thus constitutes a potential danger. It begs the obvious to say that the supplier knows or reasonably should know that the directions furnished by him will form the unsophisticated consumer’s only guide to assembly and use. Thus a product requiring assembly and use in conformity with the supplier’s directions is defective if the supplier fails to warn adequately of conditions and circumstances created by such assembly or use which would render the product dangerous to the user. Therefore, the supplier is strictly liable for injury proximately resulting from composing and furnishing a set of instructions for assembly and use which does not adequately avoid the danger of injury.
It follows that plaintiff was entitled to jury consideration of the adequacy of the instructions for assembly and use of the telescope in the context of strict liability. That right, of course, was contingent upon plaintiff’s submission to the court of an instruction properly stating the law. Plaintiff’s offered instruction on the subject (see fn. 1, ante, p. 69) was rejected. It did not condition the duty to warn on the existence in the defendant of actual or constructive knowledge of danger. As we have held, however, in these circumstances the duty to warn is not conditioned upon siich knowledge where the defectiveness of a product depends on the adequacy of instructions furnished by the supplier which are essential to the assembly and use of its product. Nonetheless, as a statement of abstract law, plaintiff’s proffered instruction is overbroad. It purports to eliminate knowledge as an element in any case of strict liability for failure to warn rather than being limited to the relatively narrow fact pattern involving a product requiring assembly and use in conformity with the supplier’s directions. The question remains, however, whether it was so far inadequate for the particular case that the trial court was justified in refusing it. We hold that it was not. There was no issue of fact at trial that the telescope was indeed a product requiring assembly and use in conformity with the supplier’s directions. Thus *75 plaintiff’s proposed instruction in conjunction with undisputed evidence was sufficient as a matter of law to place a relevant and crucial issue before the jury. The trial court erred in rejecting plaintiff’s proposed instruction on failure to warn.
The jury’s consideration of liability for failure to warn was confined to the theory of negligence. The jury was instructed in that regard that plaintiff’s contributory negligence would bar recovery for defendant’s negligence. As we view the record, the evidence does not exclude the hypothesis that the jury determined that the telescope assembly instructions were inadequate but that plaintiff was contributorily negligent in applying them. Accordingly, there is a reasonable probability that a verdict for plaintiff would have resulted had the erroneously rejected instruction been given. That error was therefore prejudicial and requires reversal.
(People
v.
Watson
(1956)
The trial court instructed that plaintiff had the burden of proving that he was unaware of the claimed product defect. Plaintiff assigns this instruction as error. The trial was held prior to the decision in
Luque
v.
McLean
(1972) 8 Cal.3d. 136 [
The judgment is reversed.
Friedman, J., concurred.
Notes
The refused instruction states: “A product is also defective if the supplier fails to adequately warn of dangerous conditions or propensities which in the absence of an adequate warning make the product dangerous to the user.”
