13 riders were injured on Six Flags Great Adventure’s El Toro roller coaster Thursday, the second safety incident on the coaster in the past two seasons.

According to an unnamed park employee who spoke to CBS New York, the injuries happened at a known rough spot, or “pothole,” just before the ride’s last turn. “From what I know, maintenance has known about it and they have tried fixing it. But for how it is, it just keeps happening,” the employee said. “The employees keep telling them that there is an issue with the pothole and maintenance has done nothing about it.”

The New Jersey Department of Community Affairs told the Asbury Park Press the witnesses reported hearing a loud bang and seeing the coaster train jolt during the run on which guests came off injured — but the coaster did make it back to the station.

“Several guests reported back pain and minor injuries after riding El Toro last evening,” Great Adventure spokesperon Garbriel Darretta said. “Thirteen guests were evaluated at the park, of which five were taken to a local medical facility for evaluation, where they were treated and released.”

In a statement released Friday, Six Flags Great Adventure said:

The ride completed its normal cycle and all guests exited the ride without need of assistance. The ride will remain closed for inspection. Any maintenance and repairs necessary will be completed and the ride will be re-inspected by our engineers, maintenance professionals, our 3rd party independent safety inspectors and the state of New Jersey prior to re-opening.

The 181-foot-tall El Toro opened in 2006 and is one of only pre-fabricated wooden coasters built by Intamin, the coaster firm behind rides such as Jurassic World VelociCoaster at Universal Orlando. The 4,400-foot-long coaster, with its 76-degree first drop and 70 miles per hour top speed, has been consistently named by Amusement Today’s Golden Ticket Awards as one of the world’s best wooden coasters.

In June 2021, a coaster train on El Toro had partially derailed, with the rear wheels of one car coming out of position. While no one was injured, the ride remained closed for the rest of Great Adventure’s 2021 season, and the state fined the park $5,000 for failing to immediately notify the state Department of Community Affairs. The ride reopened in April.