Could be a kinked fuel overflow or vent hose next to the filler pipe.
I've been having this problem too lately, and I never did before. I checked my stuff and it's all good. Maybe more gas stations are just moving to higher volume pumps and it's causing the fill tube to back up?
either its a gm thing like the 350 deisel or its a bad nozzle at the pump.
Looking for a Used H2 in your area?
CarGurus has 1,221 nationwide H2 listings starting at $7,000.
Search Hummer H2 Questions
Hummer H2 Experts