One look at the rising mercury is a reminder that summer is here, time mow the lawn and cool off when the chores are done with a boat ride around the lake. Fueling many of these staple to-do’s of summer is gasoline.

Although seemingly indispensable in our modern lifestyle, gasoline is one of the most dangerous chemicals with which we routinely come in contact because all of its compounds are toxic. It is extremely flammable and noxious and, when spilled on the ground, can be highly harmful to the environment and to the water we drink to beat the summer heat.

Recently there has been much concern about engine performance and storage issues with gasoline containing ethanol or E10. Because of ethanol’s affinity for water, improperly stored E10 gasoline can undergo something called “phase separation.” Phase separation occurs when the ethanol in the gasoline absorbs excess water until it actually separates from the gasoline. The gasoline then floats on top of this water/ethanol combination that sits in the bottom of the tank. Because most small engines receive their fuel from the bottom of the tank, the engine will not work. Ethanol is also a powerful solvent that will clean out the gunk and “build up” in fuel tanks and engines, resulting in clogged fuel filters and carburetors.

How to prevent these issues from occurring? Properly storing gasoline in approved containers away from living areas is one way to make sure that groundwater contamination and fire from gasoline spills don’t cause endangerment. The flammability of gasoline is also important to keep in mind. Starting a brush fire with gasoline is begging for trouble. The initial flash from burning gasoline catches many off guard and can cause major burns when the gasoline vapors in the air also catch fire.

Only buying what is needed for each job ensures not being stuck with “old” gas at the end of the season. If one stores gasoline for more than 30 days, add a stabilizer, available at most hardware and small engine repair shops, and approved for use with ethanol.

Keep the container or tank 95 percent full to allow for thermal expansion of the fuel and limit the air space, which reduces condensation and therefore water build up. If you do find yourself with old gummy or phase separated gasoline, consider it a hazardous waste. The only safe way to dispose of it is to take it in on local hazardous waste drop-off day or an approved hazardous waste disposal site (call your town office for the one nearest you).

Where gasoline is concerned, less is best, storing only what fuel we need and preventing spillage. It’s best that to limit exposure to gasoline, no matter how useful, because it is, and always will be, a hazardous material. For more information on the safe use and storage of household gasoline, visit

Most importantly, if gasoline or any other fuel or hazardous waste leaks or spills, report it immediately to the Maine Department of Environmental Protection, 1-800-482-0777. The sooner we know about it, the sooner we can determine the risk and prevent any threats to the environment and human health.


David McCaskill, is a senior environmental engineer with the Maine Department of Environmental Protection’s Bureau of Remediation and Waste Management.