The Umatilla Chemical Depot, which covers 20,000 acres of land of arid eastern Oregon, contains 3,717 tons of material, stored in 89 highly secured earth-covered bunkers. No chemical shipments were received after 1969, but by law these stockpiles cannot be now moved anywhere else. Officials at Umatilla must decide how to get rid of them. Although Umatilla is only one of eight chemical depots scattered across mainland, it has the largest collection of GB-filled M55 rockets, which specialists consider the most dangerous to store.