668.1  Fault defined.
  1.  As used in this chapter, “fault” means one or more acts or omissions that are in any measure negligent or reckless toward the person or property of the actor or others, or that subject a person to strict tort liability. The term also includes breach of warranty, unreasonable assumption of risk not constituting an enforceable express consent, misuse of a product for which the defendant otherwise would be liable, and unreasonable failure to avoid an injury or to mitigate damages.
  2.  The legal requirements of cause in fact and proximate cause apply both to fault as the basis for liability and to contributory fault.
84 Acts, ch 1293, §1
See also §619.17