Magellan Pipeline Anhydrous Ammonia Release

What Happened

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.

What We Found

We determined that the probable cause of the pipeline rupture was corrosion fatigue cracks that grew and coalesced under disbonded polyethylene tape coating. Contributing to the location of the cracking was external loading that caused bending stress in the pipe in addition to the cyclic stresses in the pipe from the internal pressure of the ammonia transported.

​​

Video

 
 
 
 
 
 
 
 

​​​​​​