What is the firefighter's rule?

In Lipson v. Superior Court (1982) 31 Cal.3d 362, 370, 182 Cal.Rptr. 629, 644 P.2d 822, the court stated that the firefighter's rule is primarily based on the principle of law known as assumption of risk. However, "a [firefighter] does not assume every possible risk he [or she] may encounter while engaged in his [or her] occupation. [Citations.] A [firefighter] assumes only those hazards which are known or can reasonably be anticipated at the site of the fire. [Citations.]" (Id. at p. 371, 182 Cal.Rptr. 629, 644 P.2d 822.)