Women who are exposed to mercury, cadmium, or vinyl chloride before conceiving seem to be especially likely to have autistic kids.

Alstom has therefore turned to tried-and-trusted nickel-cadmium ones instead, and GE is testing sodium and iron-chloride batteries.

To make these cadmium telluride cells, a thin layer of cadmium chloride is applied to the solar cell, and then heated up in a furnace.