More than 600 million gallons of used motor oil are generated in the U.S. each year. Approximately 250 million gallons are disposed of improperly each year. Used motor oil pollution is a quiet but dangerous problem. Used oil contains toxic substances that can kill plants and animals, spoil water supplies and even cause cancer.
"SP268-J-Proper Disposal of Used Motor Oil," The University of Tennessee Agricultural Extension Service, E12-4315-00-003-01 SP268J-IM-10/00 (Rep), http://trace.tennessee.edu/utk_agexmach/2