As you can imagine, over the years we have cleaned a countless number of oil tanks. From time to time we encounter strange things inside a tank, from alarming items such as lighters, to the remains of a makeshift dip stick. One thing we do also encounter on occasion are dead birds. During a tank clean in Liverpool this morning which involved a small 700 gallon tank in a ground floor room, we discovered no less than 10 birds that had suffered a terrible fate inside the oil tank. The cause of this was the external vent pipe from the tank, which was a simple open 2 inch pipe protruding from the wall. A bird can easily mistake that pipe as a safe place to nest and find themselves trapped inside the tank. If possible, a simple mesh covering the end of the vent pipe would allow the tank to breathe, but prevent any wildlife from entering the tank.