The giant explosion that destroyed a SpaceX Starship vehicle on the test stand this week was likely caused by the failure of a pressurized nitrogen tank, the company said.

SpaceX says its Starship 36 exploded due to a “major anomaly” during a routine static fire test just after 11 p.m. local time on Wednesday night.

All of SpaceX’s Texas operations — including the explosion during Wednesday’s engine test — take place at the company’s Starbase facility in Boca Chica, a beachside community near Brownsville. The site sits along the Gulf of America, about 20 miles from the U.S.-Mexico border.