Wondering how to dispose of gasoline? Maybe you didn't quite use all of the can for your lawn mower before winter or you found an old gas can hidden at the back of the shelf. Exposure to oxygen, even safely inside a gas can, makes gasoline degrade and become less combustible over time. When that happens, it's time to get rid of it safely and legally.
Shelf Life of Gasoline
The shelf life of gasoline when it's stored properly is usually three to six months. Ethanol blends usually have a shorter shelf life, up to three months, since the ethanol oxidizes quickly. Gasoline with higher ethanol levels tends to go bad even faster. If you have pure gasoline, you can expect it to last at least six months if you store it properly.
When you add fuel stabilizers to the mix, you get more life out of the gasoline. When added to fresh gasoline, a fuel stabilizer slows the oxidation process and can make the gas last one to three years. Whether or not you add a fuel stabilizer, always store gasoline in gas cans to help them last as long as possible.
Determine If Gasoline Is Bad
Age is one determining factor in gasoline, but it can also become contaminated. A visual test comparing fresh gasoline with your older gasoline helps you evaluate it. Place a little bit of fresh gas in one clear glass container and some of the older gasoline in another clear glass container.
Old gasoline looks a little darker than fresh gas and usually has a sour smell. Contaminated gas, even if it's not old, often looks much darker. You might see sediment or sludge in contaminated gasoline. If you have an ethanol blend, you might notice that the gasoline and ethanol separate into distinct layers.
Dilute Old Gas
If your gas is old but isn't contaminated, you might be able to use it with some fresh gasoline. The old gas on its own might not have the combustibility it needs, but adding fresh fuel to it can make it usable. Use fresh gas to fill your lawn mower about three-quarters of the way and use the old, but not contaminated, gas to top off the tank. This is the easiest way to get rid of old gas, and it saves you money since you don't have to get rid of the old gas you already bought.
Dispose of Gasoline
Contaminated gasoline should be disposed of properly as it cannot be safely used even if you add fresh gas to it. Check for a hazardous waste center in your area. Contact them first to verify that they accept old gasoline. You can often call your local fire department to get help finding a disposal location. Hazardous waste centers will have a designated area where you dump the old gasoline.
Transfer the bad gasoline to an EPA-compliant gas can if it's not in one already. This ensures you can safely transport it to the disposal location. Be careful when transporting it in your vehicle to prevent it from tipping, and don't smoke while you're working with the gas or transporting it in your vehicle.
What Not To Do
Even though gasoline loses its combustibility as it gets older, it's still a hazardous chemical that you need to dispose of properly. Never toss old gas in the trash, even in a container. Don't pour it down your drain, in the sewer, in water or in the ground because it creates a fire risk and contaminates the soil and groundwater. Expect to pay a fine or even face criminal charges if you're caught dumping gasoline.
Shelley Frost combines her love of DIY and writing in her freelance career. She has first-hand experience with tiling, painting, refinishing hardwood floors, installing lighting, roofing and many other home improvement projects. She keeps her DIY skills fresh with regular projects around the house and extensive writing work on the topic.