The Dangers A leaking fuel oil tank can become a serious fire and environmental hazard. Whether the tank is located inside or outside the home, a spill can contaminate groundwater affecting private wells or other nearby drinking water supplies. One cup of fuel oil can contaminate enough water to fill an Olympic-size swimming pool, and in many cases hundreds of litres of oil seep into the ground before a spill is discovered. Fuel oil that has spilled into a residential basement can also pose a serious health hazard, threatening indoor air quality. Anyone who owns a fuel (2 comments)