I had a 2002 Santa Fe and we were smelling gas whenever we filled up. Tried a new gas cap, checked the lines, nothing.
Eventually we checked the filler neck. On the 2002 there was a cover to 'protect' the filler neck in the wheel well, but dirt could fly up and catch inside the cover. When I removed it, I saw the area where the filler neck was packed with dirt.
The dirt had retained moisture, and rusted out the filler neck. So, when we would fill up gas would soak into the dirt, thus the smell. But the dirt was enough to keep any leaks from dripping to the ground.
I never did get around checking the fuel filter (replaced it with a 2010 Tuscon), but replacing the filler neck solved the gas smell problem for us.