Can long term exposure to certain chemicals cause hair loss?

Yes: Whether or not a particular chemical is causing the hair loss would depend on the chemical. You should discuss with your doctor to make sure there's no other medical reason for the hair loss.

Unlikely: Thallium poisoning is famous. Do you have any enemies? Hopefully you are not around plutonium. If you're having hair loss that's not male pattern baldness, the usual workup is in order, especially a thyroid check. If this is unproductive, it's unlikely that any chemical exposure will be found as the cause.