The use of 1080 in New Zealand as a pesticide is a contentious issue, with the majority of the debate occurring between conservationists and hunters. Concerns are also raised about security of potable water supplies in areas where 1080 is applied. Worldwide, New Zealand is the largest user of 1080 (sodium fluoroacetate). 1080 is a commonly used pesticide since it is very effective on mammals. New Zealand has no native land mammals apart from two species of bat and there are many introduced mammal pests that require control. The first trials were carried out in New Zealand in 1954, and by 1957 its use had become widespread. 1080 baits are used through ground based and aerial application to control possums (an animal pest introduced from Australia) and other introduced mammalian pests.