Solar modules contain lead for soldering and some contain cadmium telluride (CdTe).[1] If handled and recycled correctly, the risk of exposure of lead and cadmium into the environment is minimal. However, there is a possibility that such materials are released by accident (fire, cracks) or improper disposal. That is why there are demands that solar modules containing CdTe should be basically abandoned, as there exist alternatives. However, the overall risk appears to be comparable to that of other products containing these materials, such as many consumer electronics.

[1] CdTe has a low toxicity. However, it may pose a significant hazard if its cadmium is released by some chemical reaction, which cannot generally be ruled out.