One out of 20 people who change their own motor oil ? or 2.3 million people ? use disposal methods that could harm the environment, according to a survey by the Bureau of Transportation Statistics (BTS).

These people who use improper disposal methods said they pour the motor oil ? several quarts at a time ? down a drain or on the ground or place it in their garbage. The U.S. Environmental Protection Agency (EPA) estimates that just one gallon of used oil has the potential of contaminating up to one million gallons of drinking water, meaning improper disposal methods could have serious environmental impacts.

Three-fifths of those using improper disposal methods said they had never heard of recycling used motor oil or there was no oil-recycling center in their town. The remaining 40 percent said they did not know where their recycling center was located or the location of the recycling center was not convenient.

About 43 million U.S. residents said they change their own oil. The majority ? 35 million ? said they dispose of their used motor oil by taking it to a recycling center or a gas or service station. EPA estimates that if improperly disposed oil were properly managed the United States could save thousands of barrels of oil each day. Used oil that is properly handled can be re-refined into lubricants, processed into fuel oils and used as raw materials for the refining and petrochemical industries.

The EPA suggests taking used oil to a public used oil collection center, such as a service station or lube center. Also, the public is urged to look for the ?oil drop.? It is the petroleum industry?s symbol indicating a location where used oil is collected for recycling or reuse.

BTS surveys 1,000 households regularly for its Omnibus Household Survey. The question about disposal of used motor oil was asked during three months earlier this year.

Complete results of this or other surveyed topics from the BTS Omnibus Household Survey can be found at www.bts.gov/omnibus.