Gas fume smell coming from air vents

So I have been having this problem for a while now. Whenever I have the air or heat on in the car, the smell of gas fumes comes through the vents, it stinks really bad. It’s only when the ac/heat is off or its on recirculation that the smell doesn’t come through. Also, when standing outside even a decent distance away from the car this strong smell is noticeable. One other symptom is a loud humming towards the front of the car. Since this is most likely an exhaust problem, could it mean I have been breathing in carbon monoxide or basically huffing gasoline fumes? How toxic to the health of the driver/passengers is this car problem?

Please check the exhaust system and fuel system for leaks.

The smell of gas is different from the smell of exhaust. If you are smelling raw gasoline when the vents are pulling air from the base of the windshield, that likely means you have a fuel leak under the hood. That's very dangerous as there is a lot of heat under the hood and your car may catch on fire. That's very dangerous for the driver/passengers, bystanders, fire fighters, first responders, etc.

If you're smelling exhaust fumes, you likely have an exhaust leak somewhere under the hood as well (exhaust manifold, pre-catalytic converter, flex pipe, down pipe, EGR tube, etc.). This is also dangerous to the driver/passengers for the reason you mentioned.

Either way, you know something is not right with the car and you should either get it fixed or stop driving the car. If it's a fuel leak, it may not even be safe to stop driving the car without getting it fixed.

-Rod

Cabin filter?

I had this issue with a GMC Safari a while back.
When I replaced the "charcoal canister" .

I think it filters the gases from the gasoline.

I had this issue with a GMC Safari a while back.
When I replaced the "charcoal canister" .

I think it filters the gases from the gasoline.

Right, the carbon/charcoal canister collects fumes from evaporation and will introduce them in to the intake when the engine is running. The canister can take on fuel if someone overfills the fuel tank, such as folks who like to round to the nearest dollar after the gas pump shuts off when refueling. Often the fumes from a saturate carbon canister will also be noticeable from outside the vehicle, and usually from the rear of the vehicle.

-Rod