MP Michael Dugher has demanded answers from Alton Towers after a Barnsley couple were seriously injured.
Mr Dugher has written to Nick Varney chief executive of Merlin Entertainments which runs Alton Towers.
Leah Washington, 17, from Gawber, and Joe Pugh, 18, from Ardsley, were both hospitalised after suffering serious injuries on The Smiler rollercoaster on Tuesday, June 2.
Miss Washington has since had her leg amputated and Mr Pugh has suffered two knee fractures and extensive hand injuries.
Mr Dugher said: "It is simply horrifying that this young Barnsley couple travelled to Alton Towers for a day of fun and were involved in a terrible incident like this. We need answers now from Alton Towers."
Health and Safety Executive Officials are working on site at Alton Towers and have since closed The Smiler and two other attractions as their investigation into the incident progresses.