On Saturday, a 10-year-old South Jersey girl became at least the fifth rider to be thrown to death since 2000 from the Sizzler, a spinning carnival ride. She wasn’t wearing a seat belt, which some other states require.

State investigators continue to probe how Hailey McMullen was ejected from the Sizzler, a ride that has been a staple at many traveling carnivals for decades.

Manufactured by Wisdom Rides of America in Merino, Colo., and operated by Skelly’s Amusements of Williamstown, Gloucester County, the Sizzler turns in one direction as people sitting in its carriages spin the opposite way. Experts in the safety of amusement rides described it as safe, despite the fatalities.

“You have to keep your fanny in the seat, your back against [the] seat-back, your feet on the floor, and your hands on the lap bar,” said Ken Martin, a Virginia-based safety consultant. “When the ride is operated per the manufacturer’s instructions and the patrons follow the manufacturer’s instructions, it is one of the safest rides on any midway.”

Martin said in his opinion all amusement rides should have seat belts.

“The key thing,” he said, “is it has to be operated properly and the people operating it and the people using it have to follow the rules.”

After a 2004 accident in which a man was fatally ejected from the ride at a Massachusetts church fair, that state shut down the Sizzler until operators installed seat belts. A spokesperson for the Massachusetts Department of Public Safety said there has not been a serious incident since it required belts.

Members of the Deerfield community have expressed grief and shock over the death of McMullen. A man who answered the door of the fifth grader’s home Monday evening declined to talk. “Please let my family grieve,” he said.

One family friend posted on Facebook how she loved watching the “sweet little girl” grow up:

“No more watching her climb trees, play hide n seek, drawing in the driveway, climbing my red maple tree, the giggles and the bond she had with her sister. I cannot put into words the heartbreak I feel for the family most of all but also for our Community, Committee members and Skellys Amusement Rides. I know first hand the devastation of this tragedy they feel and will struggle with. Prayers and heartfelt condolences will help with healing not anger!" The friend didn’t respond to a reporter.

A Dollar General store near the festival tied balloons around a parking poll — a unicorn, Disney princesses, L.O.L surprise dolls. A note to customers said:

“Remember to kiss + hug your kids + tell them you love them.”

Skelly’s Amusement said that this was the first time that someone had been ejected from the ride it calls the “Xtreme” in the 27 years it has operated it in New Jersey, Pennsylvania, and Delaware.

“Nothing even close to this,” said Rick Marchione, the company’s concession manager. “Common incidents ... are bruised knee or bruised elbow — minor incidents.”

Marchione said riders are secured with a lap bar that locks in place.

Experts also said New Jersey is one of the strictest states when it comes to overseeing amusement rides.

The state Department of Community Affairs (DCA) inspects all rides at the beginning of the season. For rides that move from festival to festival such as Skelly’s Super Sizzler, the agency’s Carnival and Amusement Safety Unit also inspects the ride after they are assembled at each location. In addition, according to a state spokesperson, inspectors often inspect rides while in operation.

The DCA did not respond Tuesday to questions about seat-belt requirements. Nor did the department provide public data on amusement-ride accidents in the state.

Three members of the New Jersey Carnival Amusement Ride Safety Advisory Board said that in their years on the board, no issues had come up regarding the Sizzler.

Al Belmont, who sits on the advisory board but spoke as an industry expert from his years operating children’s rides, said that before a ride is allowed to operate in New Jersey it goes through rigorous testing by engineers and inspectors.

“I know rides that weren’t allowed to operate in the state that were coming from Europe that [state officials] didn’t feel" were safe enough. “I know for a fact they have refused licenses and permits. ... They don’t cut corners.”

Investigators have released the ride to Skelly’s and the company has since dismantled it, Marchione said. Pending investigation, the company has not been cleared to operate the Sizzler. The Deerfield festival was its last event of the season.

State police and the DCA said their investigations are ongoing. The U.S. Consumer Product Safety Commission, which has regulatory oversight of mobile amusement rides, is also investigating Saturday’s fatality.

Before this weekend, the most recent death on the ride appears to have occurred in 2016 when 16-year-old Samantha Aguilar was killed at an El Paso, Texas, church festival. A lawyer for the Aguilar family said that because a lawsuit against the operators of the ride and festival organizers settled, there wasn’t a determination why the teen died — despite the ride having both a lap bar and a seat belt.

“We had our theories. Defense counsel had their theories,” Steven Ortega said, declining to specify. “We felt there was some negligence.”

In 2007, Wisdom put out a bulletin recommending that operators install seat belts on the Sizzler to prevent further incidents. Wisdom did not respond to multiple requests for comment.

Marchione, who has worked for Skelly’s for 20 years, said that "to best of our knowledge we’ve never been notified that there was an option” for a seat belt on the Sizzler.

Staff writer William Bender contributed to this article.