A century-old tin of antiseptic, known as picric acid, was found at Waikawa & Districts Museum in the Catlins on Tuesday by a visiting Southland District Council roving museum officer.
The discovery led to a bomb squad being called to the museum yesterday.
Museum vice-president Janette Buckingham yesterday said the officer had spotted it in a medicine kit.
It had been at the museum since 1982, donated by a local, C. McKenzie.
"We’ve had it on display, quite harmless-looking."
"Until we have a conclusion, it could be just a great big storm in a teacup. We don’t know that it is hazardous, it is potentially hazardous."
Her understanding was that it could crystallise over time and become explosive.
"After she alerted me to it, we didn’t dare touch it.
"It hasn’t been handled, it’s just sitting there doing nothing. But it’s the fact that it’s there.
"Knowing what we know now, you would be very uneasy about it, so we had to evacuate the museum."
A Southland District Council spokesman said identifying possible hazards was ongoing work by the roving museums officer in conjunction with museum staff.
"It is not recommended that untrained staff should handle anything they think is potentially hazardous. They should contact emergency services immediately."
The officer who found it drew it to the attention of the museum attendant, who contacted the local fire chief.
The area was cordoned off and secured and the bomb squad alerted.
He said the officer recognised the acid as the possibly hazardous substance commonly used in World War 1 first aid kits as a treatment for burns and skin lesions.
A similar incident recently in Hawke’s Bay involved the substance being found in the collections at the MTG Hawke’s Bay museum and gallery building during a routine check.
The New Zealand Defence Force explosive ordnance disposal unit based in Christchurch was notified and sent a team down to Waikawa yesterday to assess the situation and dispose of the substance safely.
A defence force spokesman said the disposal unit recovered a small quantity of picric acid which was subsequently destroyed through a controlled demolition.
“Picric acid is a yellow, toxic substance. It is classified as a flammable solid when wetted with more than 30% water, and a high explosive when water content is below 30%. Dry picric acid is sensitive to heat, shock and friction.
“If a member of the public finds any items or substances that they are unsure about, they should contact the NZ Police to ensure their safety and the safety of those around them.”
Ms Buckingham said everyone was just doing their job.
"The fire crew is just doing their job, as was the museum officer yesterday who was working with me."
They were allowed back to the museum after the substance was taken care of.
