well, if (as you claim) no real testing has been done, how can you say it is NOT safe? It goes both ways.. it may be, it may not be. But that is an aside, the reality is that there has been scientific research on the chemical.
Based on long term empirical observation, it is safe and has not caused a single problem (it has been in use for a hell of a lot longer than you've known about it).
if you want information on the pharmalogy / scientific research on salvia and its effects on humans, read the books "Ethnopharmacognosy and Human Pharmacology of Salvia divinorum and Salvinorin A." by johnathan ott, and
"Salvinorin;
The Psychedelic Essence of Salvia Divinorum" by D.M. Turner (ISBN: 0964263629)
If you want to view more non empirical scientific data, start here:
http://www.sagewisdom.org/ and scroll down, the site cites over 70 scientific journals on salvia.
Please don't talk about it if you dont know it, thanks.