Summary: "In 1968, thousands of sheep died mysteriously in Skull Valley, Utah. The cause was traced back to a nerve agent test conducted by the US Army at the Dugway Proving Grounds. The test involved an airplane spraying a potent nerve agent called VX over a remote section of the Utah desert. However, due to a malfunction, the chemical continued to leak from the plane as it climbed to a higher altitude. Strong winds carried the nerve agent to Skull Valley, causing the death of the sheep. Despite evidence pointing to the nerve agent as the cause of the deaths, the Army has not officially taken responsibility for the incident."