Nops Meditation is not completely safe to practise and must be done with care, and with proper guidance from a teacher. There are thousand ways to do right things in wrong ways. Similar question can be is water a safe liquid to drink and again the answer is nops water is not completely safe to drink. Drinking too much water at the same time can be fatal as well as it dilutes digestive system acids and must be taken in small amounts. Now back to meditation safety, yes you will find lots of positive effects of meditation, developing intuitive capabilities, relaxation of mind and body and lots more, but as meditation is an exercise, it cannot be labelled as completely safe.
In India there are lots of myths or stories which says that a sadhu meditated for years and then god appeared and granted him / her any wish of his / her choice. Yes the sadhu may have meditated for long or even for years, but were we there when the sadhu was doing meditation ? When we hear a story, we draw a picture in our mind about how he / she might have done meditation for so long, but as there is no proof or video footage, our imagination picture may have loopholes & we must not follow anything that is not completely proved or is just a story.
In case you are interested in doing meditation for whatsoever purpose, the first step must be taken with extreme caution and care. Grabbing a book and joining a meditation course can be a good idea. A Meditation book can give you the much needed information, clear out any misconception and having a teacher to answer your questions can be wonderful. Out of all things, you must understand that you are not the only person who is planning to learn meditation and lots of other people have learn the art of meditation and in case some teacher is ready to impart you training and answer your questions, there seems to be no reason as to why not you should spend few bucks for the course fee and learn from his / her experience. Yes various books and audio / video cds can provide you information about various meditation techniques, but who is going to answer your questions ? On internet you may find meditation forums where people share their experience, but still as any other type of exercise, meditation should not be done with unanswered questions and you must proceed ahead with extreme caution and care.