A SpaceX Starship rocket exploded in a huge fireball on a test stand late Wednesday during preparations for its next launch at the Elon Musk-led company’s base in South Texas.

The upper stage Starship vehicle experienced a “major anomaly” before starting a test fire at around 11 p.m. local time, SpaceX said on social media.

All personnel were safe and there were no hazards to the residents of nearby communities, SpaceX, a commercial space launch company, said. It warned people to not approach the area while it was conducting safety operations in conjunction with local officials at the test site and the surrounding area.

In a posting on the social platform X, Musk said initial analysis indicated a storage container containing pressurized nitrogen failed.

“If further investigation confirms that this is what happened, it is the first time ever for this design,” he wrote.

The Federal Aviation Administration, which issues commercial space licenses, did not immediately respond to a request for comment made outside business hours.

The largest and most powerful rocket ever built, Starship is central to Musk’s dream of one day sending humans to Mars. It has had a mixed record so far, however, with multiple setbacks. Some test flights have ended in dramatic explosions.

The last Starship test mission in May sent the rocket’s upper stage to space but a propellant leak caused the vehicle to spin out of control and break up, leaving debris falling into the Indian Ocean.

Starship’s seventh and eighth tests previously ended with the rockets exploding.

The rockets are launched from SpaceX’s complex in the recently incorporated town of Starbase in Cameron County, Texas.

The Cameron County Precinct 1 Constable’s Office said on social media that the rocket had exploded during a routine static fire test, and that no injuries were reported. It said an investigation into the explosion was underway.