A lawsuit has been filed against Six Flags after a roller coaster accident resulted in head injuries for 2 riders. The accident occurred on July 7th when one of the carts on the coaster partially derailed. The roller coaster accident occurred when a tree branch fell on the track, hitting the first car and causing the cart to derail. According to NBC Los Angeles, 22 riders were left suspended for several hours and four people were later treated for injuries.