Required elements for strict liability based on failure to warn:

1. that the defendant manufactured or sold the product;
2. that the product had potentials risks that were known or knowable at the time of manufacture or sale;
3. that the potential risks presented a substantial danger when the product is used or misused in a reasonably foreseeable way;
4. that ordinary consumers would not have recognized the potential risks;
5. that defendant failed to adequately warn of the potential risks;
6. that plaintiff was harmed; and
7. that the lack of sufficient warnings was a substantial factor in causing plaintiff’s harm.

(CACI 1205.)

Required elements for negligent failure to warn:

1. that the defendant manufactured or sold the product;
2. that the defendant knew or reasonably should have known that the product was dangerous or was likely to be dangerous when used or misused in a reasonably foreseeable manner; a
3. that the defendant knew or reasonably should have known that users would not realize the danger;
4. that the defendant failed to adequately warn of the danger or instruct on the safe use of the product;
5. that a reasonable manufacturer or seller under the same or similar circumstances would have warned of the danger or instructed on the safe use of the product;
6. that the plaintiff was harmed; and
7. that the defendant’s failure to warn or instruct was a substantial factor in causing the plaintiff’s harm.

(CACI 1222.)

Cases Discussing Duty to Warn

Generally speaking, “manufacturers have a duty to warn consumers about the hazards inherent in their products.” (Anderson v. Owens-Corning Fiberglas Corp. (1991) 53 Cal. 3d 987 at 1003.) “The requirement’s purpose is to inform consumers about a product’s hazards and faults of which they are unaware, so that they can refrain from using the product altogether or evade the danger by careful use.” (Id.) “Typically, under California law, we hold manufacturers strictly liable for injuries caused by their failure to warn of dangers that were known to the scientific community at the time they manufactured and distributed their product.” (Id; see also Carlin v. Super. Ct. (1996) 13 Cal.4th 1104, 1108.)

Sophisticated User Defense

“A manufacturer is not liable to a sophisticated user of its product for failure to warn of a risk, harm, or danger, if the sophisticated user knew or should have known of that risk, harm, or danger.” (Johnson v. American Standard, Inc. (2008) 43 Cal.4th 56, 71; see also CACI No. 1244. Affirmative Defense—Sophisticated User Judicial Council of California Civil Jury Instructions (2017 edition).)

In order to demonstrate that the "sophisticated user" defense applies, the defendant must

1. “identify the relevant risk,
2. show that sophisticated users are already aware of the risk, and
3. demonstrate that the plaintiff is a member of the group of sophisticated users.”

(Buckner v. Milwaukee Electric Tool Corp. (2013) 222 Cal.App.4th 522, 535.)

Restatement Second of Torts, Section 388 and the Obvious Danger Rule

“Section 388 provides that a supplier of goods is liable for physical harm the goods cause if the supplier knows, or should know, the items are likely to be dangerous, fails to reasonably warn of the danger, and “has no reason to believe that those for whose use the chattel is supplied will realize its dangerous condition.” (Johnson v. American Standard, Inc.(2008) 43 Cal.4th 56, 71.) “Comment k to section 388(b), is entitled “When warning of defects unnecessary,” and it emphasizes this point.” (Id.) “It declares that although the condition may be one that only specialists would perceive, the supplier is only required to inform the users of the risk if the manufacturer has “no reason to believe that those who use it will have such special experience as will enable them to perceive the danger[.]” (Id. citing Sec. 388(b), com. k, p. 307.)