How many hours can a Haz mat cdl driver work in one day?

The HOS is the same as for any other CDL driver. The 14 hour clock starts when you do your pre-trip inspection. From that point, you can drive up to 11 hours within that 14 hour time period. Once that 14 hour period is up, or you've driven your 11 hours, you must take 10 consecutive hours off duty before you can drive again.