Electrolytic capacitor manufacturing process and the effect on the environment
I can't think of any electronic component that does not handle carcinogenic materials.  epoxy vapours, fuming arsenic, tantalum , instant adhesive, Hazardous polymerization etc.  But the MSDS sheets do not always indicate this.  ( The Chinese label just says  "Blue" and immediate toxicity to skin, inhaled or injested )

I recall a process engineer who setup many of the Gallium Arsenide (GaAs) processes in the early 70's. He said a thimble amount of fuming arsenic if released could wipe out an entire stadium. So they have stringent safety measures and airborne sensors.

Even in grid Power systems using SF6 insulation gas, creates toxic chlorine gas if it leaks.

More people died of chlorine affixiation during 3 mile island nuclear disaster from molten PVC insulation than from radiation.

Who knows how they process waste materials?