Small engine oil changes are a source of oil pollution that is easy to overlook. A properly maintained engine should have an oil change every 25 hours, multiplied by millions of engines world wide the scope of the problem becomes apparent. Briggs and Stratton alone makes 9 million engines a year just for the North American market. The process often requires tools, drain pans, tarps, and containers. Once the oil has been changed there is an oily mess to clean up. The items used during the change each become a potential source of contamination that require careful handling.