Dario Franchitti will spend the night in hospital after suffering back and leg injuries following a terrifying crash in the second race at the Grand Prix of Houston.

Franchitti’s Honda-powered Chip Ganassi machine was launched into the air, slamming into the catch fencing on the  last lap of the race at the Reliant Park circuit.

Takuma Sato and EJ Viso were also involved in the massive wreck but escaped unscathed.

The incident happened when Sato had a moment off line coming into turn five at the temporary street course.

“I got into the marbles and I lost the back end in turn five and then Dario got into me and I just hope he is okay,” Sato said.

Franchitti was extricated from his destroyed machine and transported to hospital with Ganassi reporting that he was conscious.

“I asked him if he was okay and he said ‘yeah, ah well no’, and he said his back and ankle were sore,” Ganassi said.

IndyCar has reported that Franchitti has suffered a spinal fracture, a fractured right ankle and concussion however doctors do not believe the fractures require surgery. Franchitti is expected to remain in Memorial Hermann Texas Medical Centre overnight.

Immediate concern then focussed on the crowd with debris including a large section of twisted fencing flung into the grandstand with up to 13 people suffering injuries.

Another piece of fencing was reported to have landed in front of the grandstand with the other landing on the top tier.

The Houston Fire Department reported that most of the injured were treated at the scene with two transported to hospital.

American-based Australian Leigh Diffey who was commentating on the race for NBC Sports said the Houston police had cordoned off the entire accident area and debris field.

“The local police are on the scene and had the whole area cordoned off as we were leaving the track,” Diffey told Speedcafe.com

“It was a horrific and very frightening accident for everyone concerned.

“For Dario to come away from an accident of that magnitude is a huge escape and I’m sure he would agree that it is the biggest crash of his career.”

The sickening crash took the gloss off race winner Will Power’s victory after he beat Scott Dixon with James Hinchcliffe claiming the final podium spot.

Power’s Penske team-mate Helio Castroneves suffered another gearbox drama forcing out after 53 of the 90 laps and seeing him surrender his long-held lead in the points standings.

Castroneves started from pole after qualiyfing was washed out leaving the starting order to be determined on points positions.

The Brazilian damaged his gearbox early in the race with the team performing repairs in the pits before sending Castroneves out in the hope of salvaging points however it proved futile.

Castroneves went into the race with an eight-point lead but will now go to the final race at Fontana in two weeks spotting Dixon a 25-point advantage.

“I have faith in this team that we can still do it,” a floored Castroneves said.

There is a maximum of 54 points on offer at the season-ending race at the Auto Club superspeedway.

See below for Race 2 result

Points standings