A manufacturer is required to warn consumers about a danger from a product’s foreseeable use of which the manufacturer knew or reasonably should have known and that a reasonable user would not expect. But a manufacturer is not required to warn about a danger from a product’s foreseeable use that is generally known and recognized.

If a manufacturer fails to warn consumers when it has a duty to warn, the manufacturer will be strictly liable in tort for damages caused by the failure to warn—also known as a marketing defect.

Products liability laws vary from state to state and may be in a state’s statutes or in its court opinions (also known as case law or common law).

In California, product liability law requires manufacturers to provide warnings about dangers associated with the foreseeable use of their products if the dangers are known or should be known by the manufacturer and are not obvious to a reasonable user. This obligation is rooted in the principle that consumers should be informed about non-obvious risks that could affect their safety. If a manufacturer fails to provide such warnings, and a user is harmed as a result of an unforeseen danger, the manufacturer can be held strictly liable for any resulting damages. This type of liability, often referred to as a 'marketing defect,' does not require the injured party to prove negligence on the part of the manufacturer; it is enough to show that the product was defective due to inadequate warnings or instructions. California's product liability laws are a combination of state statutes and judicial decisions, and they are designed to protect consumers by ensuring that manufacturers are accountable for the safety of their products.