Product liability exceptions: misuse, modifications, inadequate warnings, and obvious dangers can bar manufacturer or seller claims. A product liability action is barred against a seller when harm arises from misuse, alteration, or modification. A manufacturer is not liable for failure to warn if warnings were given to an employer purchaser, to a purchaser of a component later incorporated into an end product, to the relevant expert class when the product is for expert use, or where the complainant was under the influence of alcohol or an unprescribed prescription drug. Manufacturers are likewise not liable for failing to warn about dangers that are obvious or commonly known to users given the product's characteristics.