The Port Neal fertilizer plant explosion occurred on December 13, 1994 in the ammonium nitrate plant at the Terra International, Inc., Port Neal Complex, 16 miles south of Sioux City, Iowa, United States. Four workers at the plant were killed by the explosion, and eighteen others were injured. The seven-story building at the seat of the blast was completely destroyed, leaving only a crater, and significant damage was inflicted to the surrounding structures. Four nearby electricity generating stations were disabled by the explosion, and the effects of the blast were felt up to 30 miles away. A high-voltage line running adjacent to the plant and over the Missouri River was damaged, disrupting power in the neighboring state of Nebraska. Two 15,000-ton refrigerated ammonia storage tanks were r