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.

The huge blast enveloped the craft as it stood upright at Starbase, before massive plumes of flames and smoke mushroomed into the night sky, video footage of the incident late Wednesday showed.