Ardent Leisure Group Ltd said on Tuesday a prosecutor in Australia’s Queensland state filed three charges against it for an accident at a theme park on a river rapids ride in 2016 that killed four people. The accident was referred to a prosecutor earlier this year by a coroner who said the Dreamworld theme park owner, Ardent Leisure, ignored warnings and failed to make adequate safety checks. All three charges come under the Work Health and Safety Act 2011 and carry a maximum penalty of A$4.5 million. Two men and two women, including a brother and sister, died almost instantly when two rafts collided then flipped onto the mechanical ramp of the Thunder River Rapids Ride at Dreamworld on the Gold Coast. Ardent said on Tuesday that Dreamworld had taken steps to improve safety at the park.