What is the anime where a popular soft drink kills people who drink it X times? I've got this vague memory of an anime movie I saw once a very long time ago (around 1990?) and I'd like to find it—but I've no idea of any names that were mentioned. 

A particular unique aspect of the plot was that there was some kind of new popular soft drink that was actually made as a part of an evil plan as people died or disappeared (turned to green sludge?) after drinking it X times. The setting was near-future, and I believe that the focus of the action was on some kind of sea warships, but I don't recall much more—that's why I want to find it! :)
You may be thinking of an old Miyazaki movie called Sora Tobu Yureisen. In the movie, there was a drink called "Boa Juice" which is manufactured by the evil corporation and was really some kind of poison that made people dissolve if you drank enough of it. 



This blog post has a really detailed synopsis with lots of screenshots of the movie.