This is not, of course, the only incident that has occurred at this secret base...

“In the days preceding the Dugway sheep incident the United States Army at Dugway Proving Ground conducted at least three separate operations involving nerve agents. All three operations occurred on March 13, 1968. One involved the test firing of a chemical artillery shell, another the burning of 160 U.S. gallons (600 liters) of nerve agent in an open air pit and in the third a jet aircraft spraying nerve agent in a target area about 27 mi (43 km) west of Skull Valley. It is the third event that is usually connected to the Skull Valley sheep kill.”