Few pesticides arouse such intense feelings as those between users of 1080 and opponents of the toxic substance.
Partly this is because pest-baiting campaigns in the past have killed non-target species such as dogs, cattle and deer. Graphic images of animals suffering cruel deaths feature in internet campaigns against the pesticide, which has been widely used New Zealand against pests such as rats, stoats and opossum.
But few other poisons, at least in the New Zealand context, have been studied so intensely as 1080. A strong majority of scientists support the use of 1080 in pest control, and their work has been important in devising more effective ways to spread 1080 baits and to reduce the amount of actual poison in pellets laced with the substance.
Last year the pesticide was back in the headlines with the Department of Conservation's massive poison campaign to deal with an expected explosion is pest numbers. Hundreds of tonnes of pellets containing 1080 were dumped on native forests.
Despite opposition from back-country anglers, environmentalists and some deerstalkers the programme went ahead.
In June 2011 Commissioner for the Environment Dr Jan Wright issued perhaps the most significant study on the use of 1080 in New Zealand. It was released at a time supporters and opponents of 1080 were at loggerheads with calls for a moratorium on its use. Her conclusions significantly pushed the debate towards continued use of the pesticide, though she stressed the need for its safe application.
Dr Wright said New Zealand did not have an alternative method of effectively killing possums, rats and stoats.
"While there may be an alternative to 1080 one day, if we want to keep our forests for future generations we simply cannot afford to stop using 1080. Time is not a luxury we have," she said.
"So many of our native forests, birds, reptiles and insects are unlike those found anywhere else in the world and form a distinct part of our identity. It would be a travesty to allow these to disappear."
What is 1080?
Sodium monofluoroacetate, commonly known as 1080, is a fine white powder. It has a slight odour and taste and is said to dissolve easily in water.
While manufactured 1080 is a highly lethal poison to many species, the active ingredient, fluoroacetate, is identical to a substance that occurs naturally in many poisonous plants.
These plants are found in Brazil, Africa, and Australia.
1080 comes in several forms, usually in small dyed green pellets, but also sprayed carrot baits, pastes and gels.
How long has it been used here?
1080 has been used in New Zealand for pest control since the mid-1950s and is the only poison registered for aerial drops. It is also used in Australia, the united States, Mexico and Israel. New Zealand uses about 80 per cent of the world's production of manufactured 1080.
How does it work?
Whether laid on the ground, or dropped from the sky in large remote areas, the 1080 is eaten by the animal.
If enough is ingested, the poison disrupts the process of breaking down food to provide energy for cells to function. Once the animal has run out of energy, it dies from heart or respiratory failure.
Herbivores like possums become lethargic, and usually die within 6-18 hours from cardiac failure. Carnivores experience problems with their central nervous systems and may suffer convulsions before dying.
What are the risks?
1080 is extremely toxic to many animals, and dogs are particularly sensitive.
In 2007, West Coast man Ryan Fitzmaurice's pet Labrador, Tigger, died after eating a possum that had 1080 in its system.
The possum had been poisoned by a drop near his home. Mr Fitzmaurice was offered undisclosed compensation by the pest control company. Humans are also at risk if they ingest 1080.
What measures are taken to keep the public and their animals safe?
DoC must meet strict Ministry of Health conditions before getting a permit for a 1080 operation.
DoC must also talk to communities where 1080 operations are planned, let the public know an operation is going ahead and put up signs to show areas where poisoning has taken place.
* Sources: Department of Conservation, NZ Herald, 2007