The phrase "product liability case" sounds complicated, but it's an old and pretty simple idea: The law says that a company that makes a product must make it reasonably safe. If the company doesn't do that, then it could be responsible for the harm it causes by making and selling an unsafe product. For example, if a car company builds a car and installs airbags in it, but the airbags do not deploy in a crash, then the company that made the car or the airbag, or the company that installed the airbag, may be responsible for the harm caused in that crash.   Or, what if a toy manufacturer makes toy that contains harmful chemicals or paint, doesn't tell anyone, says the product is safe, then sells it? If a child is harmed by that toy, then the child's parents may would have a claim against the toy company. Other examples would be artificial Christmas trees that are supposed to be fireproof but are not, fire alarm systems that don't send an alarm in a fire, power tools that don't shut off when they are supposed to, pharmaceuticals that shouldn't cause liver damage but do, and wheel chairs that should support a 250-pound person but break when 185-pound patients sit in them.