A woman walks past as South Korean soldiers participate in an anti-chemical and anti-terror exercise as part of the 2023 Ulchi Freedom Shield (UFS) at subway station on August 22, 2023 in Seoul, South Korea. The 11-day exercise, which features drills including the handling of chemical and biological attacks, is a regular joint exercise between U.S. and South Korean troops. (Photo by Chung Sung-Jun/Getty Images)

A labourer pulls a cart loaded with sacks of spices at a wholesale spice and chemical market in the old quarters of Delhi, India, December 19, 2016. Picture taken December 19, 2016. (Photo by Adnan Abidi/Reuters)

Only after World War II did the secret spill: Ōkunoshima, located in the Inland Sea of Japan between Hiroshima and Shikoku, was the top-secret site for manufacturing chemical warfare. When the factories were closed down, a number of exotic wild rabbits were seen freely roaming the island. They were assumed to have been the test subjects for the chemical weapons, which the military failed to eradicate when the factory was demolished.

South Korean emergency services personnel wearing protective clothing participate in an anti-terror and anti-chemical terror drill on the sidelines of the joint South Korea-US Ulchi Freedom Shield (UFS) military exercise, at a shopping mall in Seoul on August 23, 2022. (Photo by Anthony Wallace/AFP Photo)

A general view of the landslide-hit Miancu Village on July 3, 2011 in Maixian County, Sichuan Province of China. Eight people are still missing after a dormitory building of a chemical plant was hit by a rain-triggered mudslide in Maoxian County on Sunday morning. Rescue efforts are underway. (Photo by ChinaFotoPress/Getty Images)