Here's the simple answer: if you think it's dangerous, don't eat it. I think it's dangerous. I don't eat it. Many people don't think it's dangerous. They eat it. If I'm wrong, I end up giving the Splenda, Sweet-n-Low, and other manufacturers a bit more money. Or I end up a little fatter from real sugar. If they're wrong, they all die horrible contorted fiery deaths, and I will be left to go into their homes and take all their stuff (while sipping a non-aspartame diet soda).
Is it dangerous? I don't know. Yes, it supposedly breaks down into components that can be found in formaldehyde and nerve gas. But apparently the procedure to make Splenda involves a step that includes chlorine.
We're dealing with forces we still don't fully understand. (Hence all the issues of pharmaceuticals that are supposed to be wonder drugs, and six months later you see commercials that say, "Did you die taking Yufuktup
TM? If so, call the offices of Wee, Fukim, and Howe.")
If I understand the story correctly, saccharine was widely used in the earlier half of the 20th century. Then around mid-century, someone determined it was The Debbil. It was labeled a cancer-causing agent to the point that it had to have a pink "THIS WILL F***ING KILL YOU!!" warning on each Sweet-n-Low packet. It literally caused people to go develop other "safer" sweeteners like Nutrasweet. Then, not too long ago, a funny thing happened; they apparently figured out that, yes, saccharin does indeed cause cancer in lab rats... because it interacts with a certain protein found in rat pee. Saccharin to my knowledge has never caused one instance of human cancer. So they took the pink warning off the packets. Thus, Sweet-n-Low (previously labeled as dangerous) is now probably better for you than it's "safe" replacement, Nutrasweet (currently discussed as dangerous).
Sugar makes you fat. If you don't mind being fat, drink regular soda. Or, even better, just drink water.