What is the legal test for determining whether prison officials were aware of a risk to the safety of an inmate?

Baldwin, 70 F.3d 1074, 1077 (9th Cir. 1995). Prison officials are not liable, however, if evidence is presented that they lacked knowledge of a safety risk. See Farmer, 511 U.S. at 844. The knowledge element does not require that the plaintiff prove that prison officials know for a certainty that the inmate's safety is in danger, but it requires proof of more than a mere suspicion of danger. See Berg v. Kincheloe, 794 F.2d 457, 459 (9th Cir. 1986). Finally, the plaintiff must show that prison officials disregarded a risk. Thus, where prison officials actually knew of a substantial risk, they are not liable if they took reasonable steps to respond to the risk, even if harm ultimately was not averted. See Farmer, 511 U.S. at 844.