When people in Redwood City hear of product liability lawsuits, they may quickly dismiss them as being the vindictive actions of unhappy consumers. However, the law does not simply allow an unsatisfied customer to summarily pin a problem on a manufacturer. Cause must first be established before one can have any hope of making a liability claim hold up to scrutiny.
The law recognizes two different types of causes that are related to liability: actual and proximate. Actual cause is fairly straightforward; it is the cause in fact, or the directly relatable reason as to why an accident or injury occurred. Proximate cause, however, can be somewhat trickier. The Cornell Law School defines it as the cause that is sufficient to support a claim of liability. It need not be the only cause, but rather the one viewed as being the primary reason a product injury occurred.
There are two methods for determining proximate cause: the "but for" test or the "substantial factor" test. The "but for" test is applicable when it is believed that but for the cause, a product would have never failed. For the "substantial factor" test, the court determines whether the factors in question materially (not incidentally) contributed to the issue in question. Per the state's Civil Jury Instructions, California follows the substantial factor standard.
An example of this in relation to product liability might be the collapse of shelving. If a storage shelf collapses due to a fastener failure, then the fastener is the substantial factor. Yet if the fastener is said to support a certain weight limit, and the user exceeds that weight limit, then the fastener failure may be said to only have contributed incidentally to the collapse.