I attended three different high schools and did not feel that any of them had a dangerous environment. The main reason for this is that there was not any great degree of bullying or anything like that. Of course, there were fights at all of the high schools I attended. If you said the wrong sort of thing to the wrong sort of person, you could get in a fight. But that is pretty normal and not the sort of thing that I would classify as dangerous. My high schools did not have gang presences and while there were drugs around, it was not as if anyone was forcing them on us or having fights over them.
Overall, my high schools were pretty mellow places. People could be mean and there could be fights, but they were not dangerous places.