I had 4 loads of mulch loaded in my 2017 gmc canyon in early june 2019. some mulch fell between the cab and cargo box where it smoldered on top of the truck gas tank for weeks until it melted tubes prompting onstar to send me two emails 6-27-19 and 6-29-19 to see my gmc dealer within 7 days for "an issue with the emission system". the dealer ignored my first visit and may have ignored the second but now the vehicle would not allow me to pump gasoline due to a melted tube and other parts on top of the fuel tank. i discovered that the gap that all pickup truck have, had nothing to direct mulch away from the fuel tank. if i had any idea this was happening i would have covered the gap with a tarp while having mulch dumped in. i feel very lucky to be alive. my wife and i took a long drive and the truck then parked in our attached garage while we watched tv a few feet away. i can't help but wonder if this is the first time this has happened or have many been killed in mysterious explosions that destroyed the evidence. *js