Environmental Impact
Gruinard Island

Gruinard Island is just off the mainland, in Gruinard Bay, half way between Ullapool and Gairloch in the Highlands. In 1942, it became the focus of the UK's secret effort to find a weapon capable of defeating the Nazis.

To test the potency of their biological arsenal, War Office scientists took a flock of 60 sheep to Gruinard and exposed them to a bomb packed with the anthrax spores.

The island, Gruinard, was so contaminated that it was deemed out-of- bounds for almost 50 years.


Anthrax can be contracted by skin contact, ingestion or inhalation, but it is through inhalation that it is at its most deadly and proves to be fatal in about 95% of cases, even with medical treatment.

Experts on biological weapons have suggested that 100kg of anthrax sprayed on a major city could kill more than 3m people.

When anthrax spores are inhaled death usually takes around seven days and will be as a result of symptoms like internal bleeding, blood poisoning or even meningitis.



Initial symptoms after inhalation might include mild fever, malaise, fatigue, coughing and, occasionally a feeling of pressure on the chest.

It was previously not uncommon for animal workers to become infected with anthrax through skin contact - it was called woolsorter's disease at one point - when a boil would appear which would eventually form a black centre.

When scientists experimented with anthrax on Gruinard Island a film was made of their work and it remained classified until 1997.

Sheep were taken to an open field, secured in wooden frames, and exposed to a bomb that scattered the spores. The sheep started dying three days later

In 1986 an English company was paid half a million pounds to decontaminate the 520-acre island by soaking the ground in 280 tonnes of formaldehyde diluted in 2000 tonnes of seawater.

Topsoil was also removed in sealed containers.

To prove that the cleanup was successful a flock of sheep was allowed to graze the island at the behest of an independent watchdog set up by the Ministry of Defence.

On 24 April, 1990, the then junior Defence Minister, Michael Neubert, made the half-mile journey from the mainland to declare Gruinard safe by removing its red warning sign - TOP SECRET.

A local, whose father's farm was one of those affected, says such was the secrecy surrounding the Gruinard tests, residents actually had no inkling of what was going on.

"There was lots of activity. It was a great fun, when you remember this is very quiet place. We just thought it was some military exercise."

With Germany defeated, 520-acre Gruinard Island was deemed off-limits and abandoned by the government.

"It wasn't for a long time after the war that we found out about the anthrax tests. We weren't worried at all about it. Nobody ever went there as far as I know,"

An unflappable breed, not all locals avoided "Anthrax Island" if there was a good enough reason. A local fisherman  admits to having ventured passed the 'Keep Out' signs.



"I've been there many times to recover loose buoys which had washed up on the beach. I didn't think anything of it."

It took the authorities the best part of 50 years to begin the decontamination of the island. Contractors were put in charge of the tricky operation of killing any remaining spores with tonnes of seawater and formaldehyde.

They were vaccinated against anthrax before they went, but were actually also at risk from the formaldehyde which is quite difficult to deal with.

Far from being a barren wasteland, the island was rich in wildlife and on a nice day very pleasant.

Having lived with anthrax for so long there was no noticeable sense of relief among the locals that the island was being cleaned up. People had even been having picnics on Gruinard's beach.