Several seriously injured passengers from the Singapore Airlines flight that encountered severe turbulence earlier this week will require spinal surgery, according to a Bangkok hospital on Thursday.

Twenty people remain in intensive care, and a 73-year-old British man died after the Boeing 777, flying from London’s Heathrow Airport to Singapore on Tuesday, hit bad turbulence over the Andaman Sea. The turbulence sent items, passengers, and crew members flying around the cabin.

A public relations officer for Samitivej Srinakarin Hospital, where most of the 104 injured people were treated, told The Associated Press that other local hospitals have been asked to lend their best specialists for the treatments. The officer spoke anonymously due to hospital policy.

Hospital director Adinun Kittiratanapaibool stated at a news conference on Thursday that none of the 20 ICU patients were in life-threatening condition. These patients include six Britons, six Malaysians, three Australians, two Singaporeans, and one person each from Hong Kong, New Zealand, and the Philippines.

Passengers have described the “sheer terror” of the aircraft shuddering, with loose items flying and injured people lying paralyzed on the plane’s floor.

The exact cause of the turbulence, which caused the plane carrying 211 passengers and 18 crew members to descend 6,000 feet (around 1,800 meters) in about three minutes, remains unclear. The flight was subsequently diverted to Thailand.

Amelia Lim, a 43-year-old Malaysian, described the chaos onboard: “I was so afraid … I could see so many individuals on the floor, they were all bleeding. There was blood on the floor as well as on the people.” She noted that the woman next to her was “motionless in the aisle and unable to move, likely suffering from a hip or spinal injury.”

Thai authorities reported that the British man who died possibly suffered a heart attack. Passengers described how the flight crew attempted to revive him with CPR for about 20 minutes.

Of the 41 people who remained at Samitivej Srinakarin Hospital on Thursday morning, 22 had spinal or spinal cord damage, six had skull or brain injuries, and 13 had damage to bones or internal organs, according to director Adinun. The injured include 19 men and 22 women, ranging in age from 2 to 83 years.

This incident underscores the unpredictable nature of air travel and the critical importance of emergency preparedness.