13-1425. Warning or directions; causation.

            If, in light of all the circumstances of this case, [an adequate warning] [adequate directions for use] would have been noticed and acted upon to guard against the danger, a failure to give [an adequate warning] [adequate directions for use] is a cause of injury.

                                                  DIRECTIONS FOR USE

            This instruction must be given in all products liability cases, whether founded upon negligence or strict liability, where failure to warn is a submissible jury issue. The instruction is to be given immediately following UJI 13-1424 NMRA. Where failure to warn or product misrepresentation are not submissible jury issues, UJI 13-1424 is the only instruction to be given on causation.

                                               COMMITTEE COMMENT

            Whether presented in negligence or strict liability, products liability based upon failure to provide an adequate warning presents special problems of causation. The jury is required to evaluate the contribution, if any, which an inadequate warning made to the plaintiff's injury. The traditional causation definition does not adequately focus this issue and, therefore, the committee has drafted this separate instruction on causation in warning cases.

            Other courts have dealt with the causation issue in a variety of ways. In Technical Chemical Co. v. Jacobs, 480 S.W.2d 602 (Tex. 1972), causation in warning cases is resolved by reference to the principle that where warning is given, the seller may reasonably assume that it will be read and heeded. A corollary of that presumption is the presumption that the plaintiff would have read and heeded a warning which the jury determines should have been provided. The presumption of causation, used in Technical Chemical Co. v. Jacobs, supra, does not conclude argument on this element of plaintiff's case. Because the presumption may be invalid, the supplier is permitted to defeat proximate cause by producing evidence that, because of some circumstance, improper use of the product would have occurred regardless of a warning. Without limiting the possibilities, this could include evidence that the user was blind, illiterate, intoxicated at the time of the use or irresponsible or lax in judgment. Cunningham v. Charles Pfizer & Co., Inc., 532 P.2d 1377, 1381-82, 94 A.L.R.3d 739 (Okla. 1974); Technical Chem. Co. v. Jacobs, supra.

            A related but separate issue is whether the product's purchaser or user should be permitted to testify as to what would have been done had a warning been provided. Such testimony can be regarded as objectionable on the grounds that it is both speculative and self-serving. Drackett Prods. Co. v. Blue, 152 So.2d 463 (Fla. 1963). Dicta in several New Mexico appellate decisions suggest that the question is proper. Demers v. Gerety, 85 N.M. 641, 651, 515 P.2d 645, 655 (Ct. App. 1973), rev'd on other grounds, 86 N.M. 141, 520 P.2d 869, on remand, 87 N.M. 52, 529 P.2d 278 (Ct. App.), cert. denied, 87 N.M. 47, 529 P.2d 273 (1974); Woods v. Brumlop, 71 N.M. 221, 229, 377 P.2d 520, 525 (1962). Advocates of a presumption of causation in warning cases argue that if such a presumption is used then plaintiffs will not be faced with the necessity of offering self-serving testimony as to what would have been done had an adequate warning been provided.

            Recognizing that this position leaves unresolved difficult evidentiary issues, the committee has determined that a presumption of causation should not be included in UJI 13-1425 NMRA until the Supreme Court of New Mexico has passed on the question raised by Technical Chemical Co. v. Jacobs, supra, and other comparable cases. The committee has simply stated a rule of proximate cause, without reference to the burden of proof, which focuses the jury's attention on that evidence which will assist the jury in determining whether an adequate warning would have been heeded.