Unfortunately, there is no easy answer. It takes only 500-billionths of a gram of this snake's venom to produce a 50 percent chance of killing the average mouse. Nonetheless, it is fair to say that untreated human envenomations from this species are almost always fatal. Many sea snakes have very toxic venoms, but almost never bite, even when handled roughly. The hands-down winner for fang length is the African gaboon viper, with fangs up to two inches long.
Several species are notorious for their readiness to bite humans.
One such species is the Russell's viper of India and Southeast Asia, which kills many people. I have watched an angry Russell's viper in Myanmar striking wildly at anyone or anything that came near it. All of the world's ten most toxic snakes are elapids, and half of these are sea snakes. One must go pretty far down the list to encounter some of the venomous snakes familiar to Americans. One generalization that emerges is that elapids are more toxic than viperids.