Lead has many uses in society. Lead can be found in batteries, in paint and in building materials. But lead environmental concerns have spurred new regulations concerning the element. About ten to 20 percent of lead exposure comes from our drinking supply, health officials said. Because of that, the Environmental Protection Agency (EPA) has regulated the amount of lead that can be found in drinking water. Until 1978, lead was found in many paints. But concerns over children ingesting the paint chips and contracting lead poisoning (among other concerns) resulted in a ban on lead based paints in 1978. However an estimated 38 million homes still contain lead based paint. The EPA is considering new methods of removing the paint safely from homes. Gasoline also contained lead until the 1970s when it was phased out due to concerns about the environment. Studies show that long-term exposure to lead can lead to some cancers, but the EPA only lists the element as a "probable" carcinogen.