While I'm not a lawyer, if I understand it; once rescheduled as long as I have a prescription for it, it's a valid substance if I "fail" the test. I could be wrong, but that was the interpretation I understand (since you can take opioids and still maintain a CDL - they verify the script after you fail for it).
Alcohol isn’t scheduled, benzos aren’t schedule 1, doesn’t mean you can be strung out on them while driving. I can write a prescription for all, doesn’t mean shit.
Rescheduling doesn’t make you a protected class, a trucking company isn’t obligated to accept that liability.