INDIANAPOLIS (AP) — IndyCar owner Roger Penske says he is certain series officials will investigate what led to a wheel coming loose during a crash in the Indianapolis 500, which ended up sailing over the catch fence and grandstands before landing on a parked automobile.

“We haven’t had a wheel come off in a long time,” Penske said. “We were very fortunate we didn’t have a bad accident.”

The cars are supposed to have a tether that keeps the wheel attached even in the event of a wreck. But when Felix Rosenqvist hit the wall in Turns 1 and 2 in the closing laps Sunday, and Kyle Kirkwood launched off the rear of his car into the catch fencing, the wheel went soaring over the fence and the corner of the grandstand before landing in the parking lot.

The wheel traveled about 350 yards before crushing into the front of a fan’s parked Chevrolet. With a crowd of more than 300,000 at Indianapolis Motor Speedway, and a full grandstand in Turns 1 and 2, it was fortunate nobody was injured.

“I saw what happened, saw it bounced on top of a building and went and hit a car over there, which obviously is very concerning,” said Penske, whose driver Josef Newgarden won the race, giving Team Penske its 19th Indy 500 victory.

Penske closed on the purchase of IndyCar and Indianapolis Motor Speedway about three years ago.

“We have tethers on the wheels, and it was a rear wheel that came off,” Penske said after Sunday’s victory celebration, “and I’m sure the guys at IndyCar will look at it, will determine what really happened.”

During the 1987 Indianapolis 500, one fan was killed when a tire flew into the top row of the grandstands. It had come off Tony Bettenhausen’s car, then bounced off the front of Roberto Guerrero’s car, before landing among the fans.

During a 1998 race at Michigan International Speedway involving CART — which later became part of IndyCar — Adrian Fernandez crashed and a tire and other parts flew into the stands. Three fans were killed and six others were hurt that day.

The next year, three fans were killed and eight injured at Charlotte Motor Speedway when a tire and other debris flew into the stands during an Indy Racing League event. The race was canceled, and IndyCar has not returned to the speedway.

Those incidents resulting in the development of the tethers that are supposed to keep the wheels attached.

The owner of the Chevrolet that took the brunt of the damage Sunday was Robin Matthews, a race fan from Indianapolis. Her car, which she calls “snowball,” had to be towed away because of the damage. She was treated with a chance to kiss the yard of bricks, and Indianapolis Motor Speedway President J. Douglas Boles gave her a lift home.

IndyCar said one person was struck by other debris from the crash but was checked and released from the infield care center.

“I was in this turn,” tweeted John Green, an author from Indianapolis. “Hugely relieved everyone appears to be OK. Watching a wheel fly over my friends at 150 miles per hour is not an experience I’m anxious to repeat.”

Rosenqvist and Kirkwood also were uninjured in the wreck, though the latter went on quite a ride. Kirkwood went airborne after contact and landed upside down against the wall, skidding several hundred yards as sparks flew from his car.

“That’s the scary part,” Kirkwood said. “You’re upside-down and you’re kind of stuck at that point.”