The X-Base Anthrax Trials of 1942 and 1943, held on Scotland’s Gruinard Island proved that airborne anthrax is highly infectious – a little too well. While the island is uninhabited, spores eventually made their way to the Scottish mainland, causing an outbreak. The island had to be completely sealed off to visitors, and locals report that the animals that remained on the island after the tests displayed genetic abnormalities for generations. The soil remained contaminated for decades until a group calling itself ‘Operation Dark Harvest’ began sending samples of it to government facilities across the UK, demanding that it be cleaned up. The entire island was sprayed with a solution of formaldehyde and seawater to inactivate the remaining anthrax, and by 1990, it was declared safe.