Following an accident that injured four riders last week, Six Flags Magic Mountain’s Ninja roller coaster was cleared to reopen on Friday. The clearance followed the completion of an investigation by the California Division of Occupational Safety and Health into the July 7 accident. 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. Peter Melton, a Cal/OSHA spokesman, said the amusement park completed its repairs and an agency engineer gave the ride a final inspection. A spokesperson for the amusement park said the ride will restart on Saturday. 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 amusement park is owned by Six Flags Entertainment Corp., a publicly traded company in Grand Prairie, Texas.