Environment & Energy

...the alternative of placing them on rooftops on combustible buildings makes this toxicity issue a very real concern, since even the ashes of the fires will be toxicological issues in the form of distributed pollution. This is especially an issue where large suburban fires at the edges of forests or grasslands take place and a large number of houses burn. We are seeing more and more of this sort of thing, particularly because of droughts driven by extreme global heating.

Cadmium ores are often sulfides, and the way to liberate cadmium is often by roasting, so the risks are clear.

There is evidence of toxicology associated with indium, chiefly represented as lung pathology.

Among many papers on the subject, which I pulled up at random among many, there is this: I-Jen Chang, Chuan-Yen Sun, Wei-Chih Chen, Ting-An Yang, Hao-Yi Fan, Yang-Chieh Brian Chen, Yu-Chung Tsao,Associations between serum indium levels and preserved ratio impaired spirometry among non-smoking industrial workers: A nationwide cross-sectional study in Taiwan Respiratory Medicine, Volume 236, 2025, 107908.

Most of the studies associated with lung disease focus on indium tin oxide (ITO) so it is not clear that indium in solar cells would have the same issues, but neither can it be ruled out.