Representatives from New Zealand have warned about the possible presence of picric acid crystals, picric acid solution and peroxide crystals in Antarctic huts used by the 20th century explorers Ernest Shackleton and Robert Scott. These chemicals are highly sensitive to disturbances and, if their existence is confirmed at the sites, will need to be disposed of carefully. But why would these potentially explosive chemicals be in Antarctica in the first place, and how big is the risk?
Where in Antarctica are Shackleton and Scott’s huts?
Shackleton and Scott’s huts are both on Ross Island. They were built just years apart, with Scott’s Terra Nova hut at Cape Evans constructed in 1911, and Shackleton’s Cape Royd hut in 1908 as part of the Nimrod expedition. These sites offered shelter to the expedition parties, and also provided space for scientific research.
In those early days of Antarctic exploration, little was known about the continent. The explorers made several discoveries, including finding new fossils, mapping the unknown South Pole and revealing the winter breeding habits of Emperor penguins – all of which were significant undertakings at the time.
What kind of work were Shackleton and Scott doing in their labs, and why would they have used picric acid?
‘Early expeditions on Ross Island carried out a wide range of scientific work encompassing fields such as chemistry, biology, geology, meteorology, ice physics, and gravitational physics,’ says Anna Clare, communications and engagement manager at the Antarctic Heritage Trust, New Zealand.
At the time of Scott and Shackleton’s expeditions, many chemicals thought of as hazardous today were used casually. ‘Picric acid was used in that era as a topical treatment for superficial burns and was sometimes a component of pre-packaged field dressings for medicinal purposes. Another use was in solution with other chemicals when fixing or staining biological tissue samples,’ Clare says. Bouin solution – a mixture of chemicals including picric acid – was especially popular at the time, and was used to preserve tissue morphology, even retaining nuclear and cytoplasmic detail.
Ether, potentially containing peroxide crystals, has also been identified at the huts. The solvent was commonly used in the late Victorian and early Edwardian era as an antiseptic. Clare notes that it was used during surgeries on humans, for example during dental procedures, and possibly also for operations on animals .
What are the new safety concerns?
In 2025, New Zealand told a meeting of signatories to the Antarctic Treaty that there were chemicals inside Scott’s hut and Shackleton’s hut that might be explosive. They noted the possible presence of picric acid crystals, picric acid solution and peroxide crystals. Sea ice conditions prevented their assessment and disposal during the 2025–26 season, and the issue was raised again this May.
Picric acid crystals can form as the water content in solution slowly evaporates. These crystals are often shock, friction or heat sensitive and when disturbed can trigger powerful explosions. Under the name melinite, picric acid was used frequently as an explosive for artillery shells after French chemist Eugène Turpin patented its use in 1885. Like picric acid solution, ether is not dangerous when liquid. But, when exposed to air, light or heat, the organic solvent can form highly explosive peroxide crystals.
However, Clare notes that the presence of picric acid and peroxides in the huts is still to be fully confirmed. ‘There is suspicion it is highly likely to be present, given the age of the collection, the common lab practices of the time, and the fact there are a small number of unidentified chemicals in the collection which bear similar physical properties to picric acid,’ she says. ‘There is confirmed ether in the collection, this is clearly packaged and labelled – however to date, crystals have not been observed.’
‘Picric acid is the perennial nightmare of laboratories,’ says Ivan Vince, chemical hazard expert at ASK Consultants. ‘It’s trinitrophenol, which, if you know your organic chemistry, is closely related to trinitrotoluene – that’s TNT. So when [picric acid crystals] blow up, it’s like TNT blowing up. In its pure form it’s not so bad, but you never get it in its pure form.’
‘And organic peroxides – similar problem,’ he adds. ‘Peroxides are unstable almost by definition.’
Vince explains that when assessing the bottles containing the chemicals, specialists would need to treat them as they would an unexploded bomb. ‘Thinking of picric acid crystals themselves: just opening the bottle – because the stopper is likely to be stuck – has caused these bottles to explode,’ he says.
What is being done to make things safer?
Antarctica New Zealand’s manager of policy and environment, Ceisha Poirot, told ABC Australia that officials had hoped to address the hazard last summer, but sea ice conditions prevented this. ‘We’re all working hard to remedy any potential risk and deal with it,’ she said.
According to Clare, experts overseeing the Antarctic huts have recommended that all identified ether is checked by a specialist chemist for any deterioration, and that any other unidentified chemicals be tested and identified to establish if there is any further deterioration risk.
New Zealand is planning work to be undertaken with the assistance of the NZ Defence Force, to identify, risk assess and carry out any mitigation required during the upcoming summer season. ‘Where a risk to humans or heritage safety cannot be managed through the safe storage of these original and unique historic artefacts, disposal may be considered,’ adds Clare.
Meanwhile, temporary rope barriers and signs have been installed to minimise chemical disturbance. Low visitor numbers further reduce the risk of disturbing the chemicals at the sites, with only 2000 people allowed to visit each year. Additional measures mean only 40 people can be in the areas surrounding the huts at any one time, with just eight people, under the supervision of a trained guide, allowed inside the huts together.
‘Safety is a priority for the Trust’s conservation teams working in the huts and work programmes have been modified until further assessment of the chemicals can be completed. Visitors to the huts also receive information about the possible chemical risk,’ Clare says.
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