My 96 4runner has the Evap charcoal canister buzz issue that I have learned to live with. But last week I was out in the desert and the every second buzz turned into a constant loud buzz and gas could be smelled under the hood. Opening the gas cap resulted in a large wushing release of pressure but once the cap was put back on the constant buzz would instantly come back at full force.

All this happened under a baking sun with temps of 105+. Later that afternoon and the next couple of days we were back to a slightly more bearable 100 and the canister was back to its normal occasional buzzing.

I don't like smelling gas vapors under the hood with everything being so hot. Is this a legitimate concern and if so what are the possible fixes?