"Black" magic is as dangerous as any other form of magick is. The thing with magick is that people forget that magick has no morals of right or wrong attached to it. There are no moral rules that deem what you can and cannot do within the practice itself. Different paths, yes, have different rules they place upon the practice of magick within that particular path, but it is not all-inclusive.
Many people will say intentions make the magick black or white. I disagree fully. Black and white are merely the labels that some practitioners place upon magick, and how they place these labels is dependent on their path. For instance, if I were to do a spell for money or for a job, some could consider it black if it requires that another must lose his/her job. However, a path that teaches the importance of not being materialistic will consider it black across the board. I, personally, may consider it white because I need it in order to survive myself.
Such is the complexity for these two overused labels. I would say, in all honesty, that it doesn't matter what label you label your magick as, it is what it is; black, white, purple, blue, orange, green, etc. To me, to call it one thing or another, to consign it to one region or another is not being true to the label itself, and one would be more accurate if you described a category of magick as what it is or what it entails, such as calling magick involving money, money magick.
Yes, your actions do have consquences, good or bad. This is true within magick as well as within the physical world. It is simple, what you do has both a cause and an effect. Whether you see that effect or not, whether you notice it at all, whether you acknowledge it, it has a cause and an effect. Sometimes those effects cause effects, such as doing something such as cursing someone on themselves. How the curse turns out may turn itself on you, if you are not careful.
There is a balance in the world, and we cannot break out of the physical laws within the universe, no mater how much we try and strive and pretend. We cannot do the things we cannot do. We cannot escape physical reality without leaving the phsyical.
No, you won't die using "black" magick, but your life could become less happy than it is now, or it could become more happy than it is now. Simply remember that your actions have consequences, consider those consequences before you do a working, and take responsibility for any action you take.
This goes for the rest of your life as well as magick.