DALLAS (Reuters) - A SpaceX rocket that burst into flames on its launch pad at the beginning of this month likely suffered a large breach in its upper-stage helium system, the company said on Friday.

An explosion on the launch site of a SpaceX Falcon 9 rocket is shown in this still image from video in Cape Canaveral, Florida, U.S. September 1, 2016. U.S. Launch Report/Handout via REUTERS/File Photo

SpaceX, owned and operated by technology entrepreneur Elon Musk, was fueling a Falcon 9 rocket on the launch pad in Florida on Sept. 1 in preparation for a routine test-firing when a bright fireball suddenly emerged around the rocket’s upper stage.

“At this stage of the investigation, preliminary review of the data and debris suggests that a large breach in the cryogenic helium system of the second stage liquid oxygen tank took place,” SpaceX said in a statement posted on its website.

SpaceX spokesman Dex Torricke-Barton declined to speculate on what triggered the breach of the helium system, saying the company was still investigating a range of possible causes.

No one was hurt in the explosion, which could be heard 30 miles (48 km) away from SpaceX’s launch pad 40 at Cape Canaveral Air Force Station. The cause of the accident is under investigation.

SpaceX said it had learned enough to conclude that whatever triggered the fireball was not related to a June 2015 accident that occurred about two minutes after liftoff. That accident destroyed a load of cargo heading for the International Space Station.

The company traced that problem to a faulty bracket that was holding a bottle of helium in the oxygen tank of the rocket’s upper stage. SpaceX replaced thousands of brackets throughout its fleet and resumed flying six months later.

“We have exonerated any connection with last year’s … mishap,” SpaceX said in Friday’s statement.

The Sept. 1 launch pad fire damaged “substantial areas” of SpaceX’s primary launch site but key areas were unaffected. The company did not provide an estimate of what repairing the damage would cost, nor how long it would be out of service.

Pad 40 would be repaired, Torricke-Barton said, adding it was too early to say when it would be completed.

The California-based firm said it would shift some missions to a new launch site at NASA’s Kennedy Space Center, adjacent to the Air Force base. SpaceX also operates a launch site at Vandenberg Air Force Base in California, which it uses for high-inclination and polar-orbiting missions.

The company is aiming to resume flights in November.

SpaceX has more than 70 missions on its manifest, worth more than $10 billion, for commercial and government customers.

(Corrects paragraph one to “at” instead of “ate”)