Two problems related to other fuel system tank filling/charging have been reported for the 2004 Chevrolet Trailblazer. The most recently reported issues are listed below.
After completely filling the gas tank, fuel began heavily pouring out from underneath the vehicle. It appears that there is a leak where the fuel hose (not sure of the exact part names) meets the fuel tank. It seems that this is a manufacturers defect as other complaints pertaining to this issue are very numerous.
Began to smell gas fumes inside the car after filling my 2004 Trailblazer. Noticed it for about 4 weeks then had the oil changed at the dealership where we purchased the car new. They informed us that there was a crack in the top of the fuel tank, where the filler tube is, and would need to replace the tank.