What's the chemical exposure from laptop repair? The biggest thing that comes to mind is flux smoke, which needs a fan or ideally a fume extractor to keep out of your face. Modern devices use lead-free solder, though I understand solder is mostly a concern for scrapping electronics for gold rather than repairing it (unless you don't wash your hands after soldering). I've gotten nasty effects from isopropyl/acetone vapors and super glue/epoxy too.

EDIT: Are they salvaging components from e-waste, or diving in dumpsters with non-computer waste as well?