- All passengers on the ride have been rescued
- Part of the Ninja ride at Six Flags Magic Mountain was hanging off the track
- Six Flags: A tree branch fell on the track, obstructing the train
- Last year, a woman in Texas died after she was thrown from her roller coaster seat
Americans love roller coasters -- until something goes wrong.
Attention turned to amusement park safety after a tree branch that fell on the tracks derailed a roller coaster car at a Six Flags amusement park Monday evening, leaving it dangling precariously and its occupants stranded for hours.
Four people were injured on the Ninja ride at Six Flags Magic Mountain, the Los Angeles County Fire Department said. Two of the four were taken to a hospital as a precautionary measure.
It was an amusement park enthusiast's nightmare. "It was just a lot of leaf noise and then cracking noises and crashing noises and a lot of screaming," Brandy Chambers, who witnessed the incident from her vantage point on another ride, told CNN affiliate KTLA.
But worldwide, such incidents are very rare, and attendance at amusement parks has been increasing, experts say.
According to the International Association of Amusement Parks and Attractions, there are 4.3 injuries per million attendees at U.S. fixed-site amusement parks, citing 2011 statistics.
In 2011, the chance of being "seriously injured" at fixed-site amusement parks in the U.S. was 1 in 24 million, the IAAPA reported.
Still, it's hard to ignore images of a roller coaster car filled with people, drooping from the track.
The front part of the roller coaster detached from the track and dangled at about a 45-degree angle, pointing to the ground.
The car was about 20 feet in the air, Los Angeles Fire Department supervisor Ed Pittmann told KTLA.
Rescue workers climbed atop the track and used a thick rope to tie the front of the car to the track above.
By late Monday night, all 22 passengers had been rescued.
Twitter was abuzz Tuesday with people claiming they would never ride a roller coaster again.
Six Flags Magic Mountain is the 18th most popular amusement park in North America, with more than 2.9 million visitors in 2013, according to the Themed Entertainment Association and AECOM global attractions attendance report. The index lists the 25 most visited amusement parks and theme parks worldwide, based on attendance figures compiled by AECOM..
The derailment happened after a tree branch fell on the track, obstructing the train, Six Flags Magic Mountain spokeswoman Sue Carpenter said.
Six Flags describes the Ninja ride as a "stealth assassin" on its website.
"The black belt of roller coasters whips you into submission," the site says.
Passengers ride the swinging coaster suspended from the track instead of riding on top of the track.
The derailment is the latest in a series of high-profile roller coaster accidents in recent years.
Last July, Six Flags Over Texas in Arlington shut down its Texas Giant roller coaster after a woman was thrown from her seat and plunged to her death.
Between 1990 and 2010, more than 92,000 children were injured in amusement ride-related incidents, according to a study by the Center for Injury Research and Policy at Nationwide Children's Hospital in Ohio. That's an average of more than 4,000 injuries per year.
The IAAPA had lower estimates for amusement park injuries -- falling from about 2,500 in 2001 to 1,200 in 2011.
Safety is on the mind of riders following Monday's derailment, and the organization provides a number of common-sense safety tips.
Among those: Obey age and height restrictions, keep arms and legs inside the ride, and report any unsafe behavior or condition to an attendant.