Soldiers claimed that they were used against their will as human guinea pigs to test out Cold War chemicals

In the years between 1945 and 1989, more than 3,400 people were exposed to nerve gas at the base, giving the site the dubious distinction of having tested more human subjects with nerve gas than any other place on the planet. Tests involved repeated exposure, entering gas chambers, tests on bare skin, and tests of mental performance.

Aerial release trials have also been held at the site, which the government says can help the U.K. prepare for potential biological or chemical attacks by air. The government says the experiments were harmless and that they did not cause adverse health issues for locals. However, many are skeptical after they admitted that World War II trials by Porton Down scientists contaminated a coastal Scottish island with anthrax.