​On October 17, 2016, shortly after 9:00 p.m. local time, an 8-inch-diameter underground transmission pipeline ruptured and released 2,587 barrels (108,654 gallons) of liquid anhydrous ammonia on private property adjacent to milepost (MP) 263.32 on County Road P in Burt County, near Tekamah, Nebraska. The pipeline was owned and operated by Magellan Midstream Partners, LP, (Magellan). Upon release and exposure to the atmosphere, the ammonia vaporized and produced a toxic plume. A local resident who had left his home to investigate the accident scene died of respiratory failure due to exposure to the ammonia vapor; additionally, two people sustained minor injuries. A total of 29 households, involving 49 people, were evacuated. U.S. Highway 75, a main roadway in the area, was closed for several days.

The ammonia pipeline was operated and monitored from a control center located in Tulsa, Oklahoma. Low pressure alerts were received in the control center at 9:03 p.m., and a rupture alarm first occurred at 9:14 p.m.At 9:21 p.m., control center personnel received a third-party report of strong ammonia odor and a vapor cloud located 8.5 miles north of Tekamah, Nebraska.

Image Credit: NTSB