SS Sansinena was a Liberian oil tanker that exploded in Los Angeles harbor on 17 December 1976 at 7:33pm.

The blast shattered windows for miles around, flung the entire midship bridge on the wharf, and triggered a fire that spread across the dock and around the tanker.

The Los Angeles Fire Department soon arrived on the scene to contain the blaze and rescue survivors.

A United States Coast Guard investigation later concluded that the incident was caused by flammable hydrocarbon vapor buildup on the deck of the ship caused by a poorly designed and deteriorating venting system as well as an unsafe practice (leaving all vents open during ballasting).

The official casualty count was: The explosion of Sansinena and technical details of the incident were featured as the first segment of the Engineering Disasters in an episode of History Channel's Modern Marvels television series.