Ammonia - again

Monday afternoon in Twin Cities: 1 trucker dies and another is seriously injured after a release of anhydrous ammonia. Wednesday afternoon on border between MN / SD: tractor-trailer accident carrying 40,000 pounds of anhydrous ammonia caused evacuation of SD town. No one killed; injuries from exposure for truck drivers. "... estimated that between 500 and 1,000 pounds of chemical leaked, creating only a small cloud."