NASCAR legend Kyle Busch died of severe pneumonia, his family said Saturday.

The 41-year-old driver died Thursday after he was hospitalized with a “severe illness,” his family said. In a new statement, they said Busch died of pneumonia that progressed “into sepsis, resulting in rapid and overwhelming associated complications.”

On Wednesday, he was coughing up blood and lying on a bathroom floor at a General Motors training facility in North Carolina, according to a 911 call obtained by NBC News.

“I’ve got an individual that’s, uh, shortness of breath, very hot, thinks he’s going to pass out and is producing a little bit of blood — coughing up some blood,” the caller could be heard saying around 5:30 p.m. Wednesday.

Busch was on a simulator at a training facility that day, NASCAR CEO Steve O’Donnell said.

Earlier this month, Busch radioed his crew near the end of a NASCAR Cup Series race in Watkins Glen, New York, and asked a doctor to give him a “shot” after he finished, The Associated Press reported. Busch had been struggling with a sinus cold that was worsened by the intense G-forces and elevation changes at the road course on May 10, according to the TV broadcast of the race.

Five days later, he won the NASCAR Craftsman Truck Series race in Dover.

Busch, who was known as “Rowdy” and “Wild Thing” for postrace fights, leaves an indelible legacy as a two-time NASCAR Cup Series champion and the winner of 234 races across the sport’s three national series — the most in racing history.

His death led to a wave of tributes from the racing community, celebrities and fans.

“A future Hall of Famer, Kyle was a rare talent, one who comes along once in a generation. He was fierce, he was passionate, he was immensely skilled and he cared deeply about the sport and fans,” the Busch family, Richard Childress Racing and NASCAR said in a joint statement.

“NASCAR lost a giant of the sport today, far too soon,” the statement said.

He’ll be honored at Sunday’s Indianapolis 500 race, with the pylon lit in his honor for Lap 18, the number of his car.

Busch is survived by his parents; his wife, Samantha; son, Brexton, 11; and daughter, Lennix, 4.

In their brief statement on Saturday, Busch’s family asked for privacy in the near future.