Petroleum products migrate to the water table many times and contaminate drinking water. Spent a good deal of my working life identifying and dealing with underground contamination. I am and am not a fan of the EPA. When it originated, a major river back east had caught fire. After doing a lot of good they ran out of good to do and then started looking for things to do to keep their jobs. I know one contractor in Arizona that had a 1,000' deep hole drilled and used that to pour his companies used petroleum products into. It penetrated 3 water tables. Locally, the asphalt manufacturing company picks up used oil from mechanic shops and uses it in the asphalt operations. There is a solution for about every problem however often it is too costly in time and money to accomplish.