Do you remember the scene in Night of the Living Dead, where the humans try to refuel the truck so they can drive into town to get medical help? Well, instead of becoming well-done zombie food, they might have made it - if Pennsylvania had had stricter environmental laws.
To set the stage, Ben (hero) and Tom and Judy (cute teen couple) have broken through the encircling zombie horde and driven Tom's truck out to the gas pump in the yard. However, the key they took from the hook marked "gas pump" doesn't work. Ben shoots off the pump lock. As Ben holds the zombies at bay with his rifle, Tom grabs the gas nozzle and runs to the truck. Unfortunately, the thoroughly rattled teenager grabs the nozzle by the trigger and sprays gas (leaded! Ugh) all over the ground and truck. Ben's torch ignites the gas on the ground. Tom jumps back in the truck to get away from the gas pump (never a good place to be in case of fire) but before he can drive off, the flames have spread to his truck. By the time he and Judy realize the truck's on fire, it's too late. The truck explodes with them in it.
Had this little drama played out in California 2008 instead of Pennsylvania 1968, the teens might have gotten away and lived to be eaten by zombies on another day. Since Night of the Living Dead was filmed, air pollution laws have been passed in many of the more polluted areas of the country to require the use of "vapor recovery" nozzles. These nozzles are designed to collect and capture the gasoline vapors that would otherwise be emitted to the air. Most vapor recovery nozzles are equipped with "insertion interlocks" which prevent gas from being dispensed unless the nozzle is stuck into the car and the vapor recovery equipment engaged.
If Tom had grabbed one of these nozzles by the trigger, it would have just clicked harmlessly no matter how hard he pressed it. He wouldn't have spilled a single drop of gasoline. His only worry would have been getting the nozzle into his truck's fill pipe just right with the zombies closing in.
Unfortunately, this minor defense against the zombie apocalypse is slowly going away. Not only are many new vapor recovery nozzles designed so that an insertion interlock isn't necessary, the need for vapor recovery nozzles of any kind is going away. All new cars these days are equipped with built in vapor recovery systems, rendering nozzle-based recovery systems moot. Requirements for vapor recovery nozzles are expected to be phased out over the next several years. Could this be what the zombies have been waiting for?