After four riders were injured last week, Six Flags Magic Mountain’s Ninja roller coaster is still being examined without an expected reopening date.

Sue Carpenter, a park spokeswoman, said the rest of the Valencia amusement park is operating as normal, but declined any further comment.

The California Division of Occupational Safety and Health is investigating the July 7 accident but did not respond for comment.

Riders were left dangling from the suspended swinging roller coaster after reports it hit a tree branch in the evening. Four riders sustained minor injuries, and 22 people were stuck on the ride for upwards of two hours.

A lawsuit has been filed against the park in Los Angeles Superior Court by attorney Barry Novack, who also is representing a rider who sustained injuries to his fingers this month on the Splash Mountain ride in Disneyland.

The Six Flags lawsuit alleged that the park’s neglect caused the roller coaster to be “dangerous, defective, hazardous and unsafe.”

The amusement park is owned by Six Flags Entertainment Corp., a publicly traded company in Grand Prairie, Texas.