Well Bruce.. I tried reading a bit on solar panel and Cadmium in general. Much of it is far too technical for me to evaluate, but I see pages claiming that Cadmium-Tellurium panels are about the most efficient, and the compound is fairly stable, requiring some pretty high temperatures to break down.
   The do say that is is prudent to develop Cadmium recovery systems IF we continue using Cadmium.

this page also suggests that it is not clear yet whether Silicon panels can be as efficient....

If I were betting man, I'd wager a nickle that both types...and maybe some others WILL be used for different applications. I'd wager whole dollar that solar will be a significant way of generating energy in the next few decades....and whatever the safety analysis, I'd wager $5 that overall, solar will be safer & cheaper than coal and nuclear. If I could live 200 years, I'd wager $20 that solar, wind, tides....etc., will be about the ONLY dependable sources beyond the falling water we now use.