Green Living

Don't Top Off Your Gas Tank

When you put gas in your car, do yourself and the environment a favor by not topping off your tank.
Don't Top Off Your Gas Tank
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Next time you put gas in your car, do yourself and the environment a favor by not topping off your tank. It may be tempting to round off your sale, but those few extra clicks can compromise the pump's vapor recovery system—and your health.

When it's working properly, the vapor recovery system creates a seal between the gas nozzle and your car to capture and safely store underground 95 percent of toxic gasoline vapors like benzene, toluene, and xylene. But when you top off, the gasoline you think you're adding to your tank gets trapped in the hose or in the rubber boot of the nozzle, which not only makes a potentially dangerous mess, but damages the system for the next customer in line.

Those lost drops have a big impact on the environment. "Spilling one ounce of gasoline produces the same volatile emissions as driving a 1996 model car 56 miles," says Bobble Bratz, project coordinator with the Santa Barbara County Air Pollution Control District in Southern California. The spillage seeps into the ground (and the water supply), and the released vapors contribute to air pollution.

Meanwhile, the Agency for Toxic Substances and Disease Registry reports that exposure to benzene (a known carcinogen), toluene, and xylene adversely affects the lungs, heart, kidneys, bone marrow, and immune and central nervous systems. And the ozone produced from volatile organic compounds that escape from gasoline into the air irritates and may damage the respiratory system.

So skip the top-off. To further reduce your exposure, use the nozzle's hold-open latch when available, stand upwind while fueling, and tighten your gas cap to prevent leaks. It couldn't be simpler to do so much good for the environment and your own health.