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How To Recycle or Dispose of Old Gasoline

July 12, 2023

Suppose your business uses a lot of gasoline-powered equipment. In that case, part of that business is managing gasoline. Particularly those gasoline cans your crews haul among job sites to motivate mowers, edgers, trimmers, pruners, augers, compactors, gensets, chainsaws, heaters, and other tools of your trade. This blog entry provides information about storing gasoline safely, salvaging stale gasoline, and how to dispose of old gas. Q&As include:

1. Can gasoline become stale?

2. How long can you store gasoline?

3. How should you store fresh gasoline?

4. How does gasoline become contaminated?

5. What is a fuel stabilizer?

6. How does stale or contaminated gasoline affect engines?

7. Can old gas be recycled?

8. How do you safely dispose of small amounts of stale gasoline?

9. How do you safely dispose of larger amounts of stale gasoline?

10. Where can you get help disposing of large quantities of stale gasoline?

­1. Can gasoline become stale?

Yes, in a big way. Especially if it languishes in old gas cans that aren’t airtight. This is because gasoline deteriorates over time when it’s exposed to oxygen. Such oxidation changes the hydrocarbons in gasoline into alcohol. These get further oxidized into aldehydes and ketones, which themselves become acids. 

This chemical drama causes the gasoline to become less combustible, so engines will not run very well, if at all. It can also cause gummy resins to form, which can clog carburetor jets (in tools) and fuel injectors (in cars & trucks).

(BTW, when you hear your neighbor’s lawn mower revving up and down uncontrollably all by itself (called surging by small-engine mechanics), it’s probably due to bad gas (see source).)

2. How long can you store gasoline?

Short answer: three months. Longer answer: pure gasoline typically lasts up to six months before it begins to degrade from oxidation. Any water that finds its way into the gasoline sinks to the bottom of the can or tank. Thus, you can avoid putting water into your tool or vehicle simply by not using the last dribble of your gasoline. 

But today, over 80 percent of all U.S. stations sell gasoline containing up to 10 percent ethanol (E10). Ethanol tends to absorb water so that water effectively becomes part of the gasoline, making it less combustible. Given this liability, it’s accurate to say that most gasoline sold at your local filling station will only last up to three months (see source).

(N.B. Many automotive technicians caution that you shouldn’t let your vehicle’s gasoline tank get below one-quarter full, just so the fuel pump doesn’t suck up all that water.)

3. How should you store fresh gasoline?

You can’t prevent gasoline from going stale. But you can put off the inevitable. So what does a fuel stabilizer do, and how can it help?:

Using a fuel stabilizer will retard harmful oxidation (see Q.5), and manufacturers generally recommend that you find “premium” gasoline that’s ethanol-free for your small gasoline engines, as well as for your Lamborghini. There’s even a “pure gas” website that can direct you to the nearest station that offers it.

Another strategy is to methodically mix older gasoline with fresh gasoline. For example, if you have a four-gallon container, top it off with fresh gasoline when it’s down to one gallon. This way, the older gasoline is fortified by, the newer, and contaminants are less concentrated across the mixture.

4. How does gasoline become contaminated?

Gasoline can become tainted with algae, water, rust, sediment, and organic matter that collects toward the bottom of its container. This is a danger if you store gasoline in your tank onsite to fill individual cans.

5. What is a fuel stabilizer?

A fuel stabilizer is a solution of petroleum antioxidants and lubricants that protects the fuel as it languishes in a can or tank. It bonds with gasoline to prevent evaporation and thus prevents it from forming gummy resins.

6. How does stale or contaminated gasoline affect engines?

Firstly, when gasoline becomes less combustible (see Q.1), it contains less energy to exert upon the piston during its power stroke. This reduces engine torque. For example, your lawn mower might stop when it hits a patch of thicker grass (where it usually wouldn’t). Or your chainsaw might keep stalling while you’re trying to do your Paul Bunyan thing.

Also, contaminants can starve an engine of gasoline by blocking the fuel filter; those that nonetheless find their way past the filter can clog injectors (in vehicles) and carburetor jets (in tools). Additional symptoms are rough idle, surging, and generally poor performance.

7. Can old gas be recycled?

Okay. Full disclosure. Hazardous Waste Experts is in the business of hazardous waste disposal. So, we admittedly have a pecuniary interest in advising you on gasoline disposal and how to dispose of bad gas professionally, with good attention to RCRA requirements. But if you insist…

You can try reconditioning stale gasoline yourself. But remember kids, gasoline is highly flammable and extremely toxic. Use caution. Work outside. Stay far away from any heat source or open flame. And bear in mind that smoking is bad for your health. All that said:

To remove foreign particles from gasoline, pour it into a new container through a coffee filter or two layers of thin cloth. (Allow the filter to dry fully, then place it in the trash.) 

Next, pour the gasoline into a transparent container. Wait until the water settles to the bottom. Then, carefully pour off as much of the gasoline as possible, leaving the water in the original container. Add isopropyl alcohol to the reconditioned gasoline to break up any remaining water: about 12 ounces of isopropyl alcohol for every 10 gallons of gas (see source). 

Of course, you wouldn’t want to pour this stuff directly into your new $6,000 Cub Cadet (or $40,000 Subaru) and hope for the best. Instead, you must mix this reconditioned gasoline with fresh gasoline in a 1:5 ratio (see source). Then start hoping for the best.

8. How do you safely dispose of small amounts of stale gasoline?

Suppose you have only a small amount of gasoline; you may ask yourself… is there a way to get rid of old gasoline? Can you dump old gas on the ground? NO. Your best bet is to take it to your local hazardous waste disposal center. If that’s not on your speed dialer, call your town or city hall. They’ll put you in touch. (Your call is important to them.) But bear in mind:

  • You should only transport gasoline in approved gas cans, preferably in the open bed of a pickup or on an open trailer. The above can also help with how to dispose of old gas cans. 
  • Never put gasoline containers inside the passenger compartment of your car or truck. If the fumes don’t get you, the ensuing explosion might.
  • If you must use the trunk of your car (not recommended), make sure the cans are well sealed, tie them down so they don’t fall over, and remove them from the vehicle ASAP after you get to where you’re going.
  • Never leave gasoline containers in a hot, enclosed space (such as in a vehicle passenger compartment or trunk).  
  • Also, it would be a good idea to steer clear of sparks, flames, or hot surfaces.

­9. How do you safely dispose of larger amounts of stale gasoline?

Suppose you have larger amounts of gasoline to manage. In that case, the Federal Motor Carrier Safety Administration (FMCSA) has an existential interest in how you go about doing so. They would remind you that gasoline is a listed hazardous material and that any private motor carrier aiming to transport it must have a minimum of $1,000,000 insurance coverage.

Also, the FMCSA is fussy about who’s splashing around in gasoline. Anyone who ships, packages, loads, unloads, labels, and or transports fuel must have hazmat certification and proper hazmat placards in place. Also, remember that the proper rules for disposing of old gasoline will vary by state and localities within that state, so check with your local hazardous waste management facility near you.

10. Where can you get help disposing of large quantities of stale gasoline?

Hazardous Waste Experts can help you with all facets of gasoline management, safely and efficiently collecting and transporting your unusable or unwanted gasoline to ensure you’re in full RCRA compliance. If you want more information on “gasoline disposal near me” Contact us today or call 877.200.2029

Disposal of hazardous waste doesn’t have to be painful.