Workers, law enforcement and members of the National Transportation Safety Board investigate the bridge collapse.

The Florida pedestrian bridge that killed six and injured 10 when it collapsed onto the roadway last year, had significant design errors, the National Transportation Safety Review Board determined at a Tuesday hearing.

The 950-ton bridge, meant to eventually link Florida International University to the nearby Miami suburb of Sweetwater, came crashing down in March 2018.

At a federal hearing on the tragedy in Washington, D.C. Tuesday, the NTSB said it was outlining the “probable cause” of the collapse before putting out its final report, USA Today reported.

“The FIGG design made significant errors in the determination of loads,” NTSB staffer Dan Walsh said of the board’s findings at the hearing, referring to Tennessee-based FIGG Bridge Engineers.

The board determined a year ago that FIGG engineers overestimated how much stress the bridge could endure, the paper reported.

Only two days before the brand-new structure went down, an engineer left a voicemail with officials and warned that some cracking had been found at one end of the concrete span.

In the voicemail, FIGG’s lead engineer on the project, Denney Pate, acknowledged that the cracking would need repairs, “but from a safety perspective we don’t see that there’s any issue there, so we’re not concerned about it from that perspective.”

Walsh also noted that the construction was at “high risk” due to the bridge’s complex design — but that the university was overseeing the project and the state Transportation Department was not required to have an inspector present.

“Our recommendations address this issue, that FDOT should have more authority on this type of project,” he added, according to the report.

The $14.2 million structure, which would have been 289 feet long and 109 feet tall at completion, was being constructed under the university’s “accelerated bridge construction” methods.

Under those methods, larger pieces are constructed away from traffic, instead of having several smaller pieces placed together above a busy road, USA Today reported.

The collapse did not appear to be a consequence of those methods, Walsh said, according to the outlet.