Retro petrol cansPhoto: Ko Backpacko (Shutterstock)

If you’ve stored gasoline (hopefully not in plastic bags or other random containers) the important thing to know is that it can get bad and after a while you won’t want to stick it in your car or lawnmower. But you shouldn’t throw it on the street either. Here’s what you need to know about safely disposing of old or expired gasoline.

How long does it take before the gasoline goes bad?

Gasoline is volatile, which means it is hardly a liquid. Its molecules all dream of escaping and floating freely in the air, and if the cap on the container is not tight enough, they will. Gasoline is also easily oxidized, meaning its molecules break apart when exposed to certain other chemicals, including oxygen. This is what makes it so flammable and so good in engines. If you oxidize fuel very quickly, it creates a fire – or a series of tiny explosions inside a car engine that move the pistons.

When gas slowly oxidizes – whether in a gas can in your garden shed – you get a series of molecules that are not exactly the same as regular gasoline. They may not propel your engine as well as they should and in some cases can clog the fuel lines.

For these reasons, you really can’t expect stored gasoline to last forever. Three to six months is about the best you can hope for when properly stored; If it’s in a loose can or has been exposed to heat, it may take even less time.

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What if you dump old gas somewhere?

You probably know intuitively that neither your city’s sewer system nor the local ecosystem will be very happy to gobble up the gasoline of an entire tank. Gas is corrosive, toxic, and flammable and just isn’t one of those places.

Draining gasoline is illegal almost everywhere – check your local laws – and the fines involved can be substantial. If you’re already trying to think of places to drain your gasoline without getting caught, you’re an asshole.

How to dispose of old gas safely

Your city or county should have a procedure for doing this, which you can look up on their website. You can also google hazardous waste disposal [your area]”To find more options.

Follow the directions, but typically here’s what you need to do:

  1. Make sure the gasoline is in an approved container (again, this is not included Plastic bags or random buckets).
  2. Call the landfill in advance to check opening times, rules, and other requirements. You might get rid of it in a moment old paint cans or car batteries at the same time.
  3. Drop it off in the right place using the approved methods and enjoy the security that comes when you remove a flammable liquid from your hands without poisoning the environment.