If you're referring to practicing it with killer whales, no one has ever died from waterworks. Also if you're referring to the incidents involving Tilikum: the trainer fell in the sea pen and it was never proven that he caused the attack. A visitor stayed after night and jumped into the tank with an animal that was already prevented from performing waterworks. Lastly, Tilikum grabbed a trainer off of the deck and brought her into the pool. The other incidents at the parks, which are very few, happened with known causes. Each one had an answer from the park and precautions were taken. Typically resulting in ending waterworks with that particular animal. There were many animals such as Kalia, Corky, Ulises, Katina (the most dominant whale), Keet, Nakai, and Kayla reportedly never having an incident. In 2014, a video was released of the trainers practicing an in water session with Ikaika (including the trainer riding on him). Work with Ulises had to stop because he supposedly liked them too much - if you understand what I'm trying to say. I'm not saying it's not a risk, but no trainer at SeaWorld has ever died from waterworks.
I was not aware that the trainers were not in the water during those incidents, so I will retract my statement about waterworks being responsible for those two deaths. It does not, however, change my opinion in the slightest.
Two of the incidents I was referring to involved Tilikum. Whether he was responsible for that trainer’s death or the other orcas were is irrelevant; it was a death by captive orca attack. The trainer killed at SeaWorld was initiating direct contact with the orca at the time, which to me carries a lot of the same risk that waterworks does. I was not referring to the incident with Dukes (note that I said “marine park employees”) because that was clearly a different situation. The other death I was referring to was at Loro Parque.
I would not say “very few” incidents have occurred from working with orcas as a whole. There have over 35 reported incidents since 1970, which averages to more than one incident every 1.5 years, and this is probably lower than the true number. I don’t know how many happened due to waterworks, but I have no doubt that bringing it back would increase the number.
Personally, I think that there’s a lot of merit to ending orca shows altogether, but I think that a protected contact, hands-off approach is at least better. Waterworks has the potential to produce deaths and injuries for no tangible benefit. Claiming that it hasn’t caused much problem yet is not a good argument: something *could* happen, and I think it would just be a matter of time and not overall likelihood.
The “cause” of the known incidents is simple: orcas are large predators whose behavior can be aggressive and/or unpredictable. All orcas are capable of hurting or killing humans, regardless of whether they have displayed such behavior. When contact occurs, it is an accident waiting to happen. Reputable zoos stopped doing shows with large carnivores a long time ago; I wish that SeaWorld would follow suit.