7.4 JONES ACT NEGLIGENCE CLAIM—CAUSATION DEFINED
Negligence under the Jones Act is a cause of an injury if it played any part, no matter how slight, in bringing about the injury or damage, even if the negligence operated in combination with the acts of another, or in combination with some other cause.
See Ribitzki v. Canmar Reading & Bates, Ltd. P’ship, 111 F.3d 658, 662 (9th Cir.1997) (holding that "even the slightest negligence" is sufficient to support a Jones Act finding of negligence) (citing Havens v. F/T Polar Mist, 996 F.2d 215, 218 (9th Cir.1993)). This test is often described as a "featherweight causation standard" and allows a seaman to survive summary judgment by presenting even the slightest proof of causation. Ribitzki, 111 F.3d at 664.
The causal requirements for Jones Act negligence and under the doctrine of unseaworthiness are different. See Lies v. Farrell Lines, 641 F.2d 765, 769 n.7 (9th Cir.1981). Separate causation instructions, therefore, will be necessary when both claims for relief are asserted.