Kyle Busch’s cause of death has been revealed.

The legendary NASCAR driver died at age 41 on Thursday, May 21, from severe pneumonia that progressed into sepsis.

“The medical evaluation provided to the Busch Family concluded that severe pneumonia progressed into sepsis, resulting in rapid and overwhelming associated complications,” Busch’s family said in a statement, per ESPN.

“The Family asks for continued understanding and privacy during this difficult time,” the statement concluded.

Busch died on May 21. Shortly before, his family announced that he had experienced a “severe illness resulting in hospitalization.”

“On behalf of the Busch family, everyone at Richard Childress Racing and all of NASCAR, we are devastated to announce the sudden and tragic passing of Kyle Busch,” the joint statement from NASCAR, the Busch family and Richard Childress Racing read.

“Our entire NASCAR family is heartbroken by the loss of Kyle Busch,” the statement continued. “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.”

According to audio from a 911 call obtained by PEOPLE, Busch was coughing up blood and lying on the floor of a bathroom when an ambulance was called on his behalf on Wednesday, May 20.

“I’ve got an individual that’s [got] shortness of breath, very hot, thinks he’s going to pass out, and he’s producing a little bit of blood, coughing up some blood,” the caller told emergency responders around 5:30 p.m local time. “He is awake. He’s awake on the bathroom floor right now.”

Busch had been scheduled to race in the NASCAR Craftsman Truck Series race in Concord, N.C., on Friday, May 22, and in the Coca-Cola 600 on Sunday, May 24, at Charlotte Motor Speedway.

Busch was hospitalized days after he requested medical attention after finishing a race on May 10 at Watkins Glen International. He was heard over the radio asking his team to have a doctor ready to meet him at his bus because he was going to “need a shot.”

During the television broadcast, it was said that Busch was struggling with a sinus cold that was exacerbated by the “intense G-forces and elevation changes” at the course, according to the Associated Press.

Busch quickly found success in racing, having won the NASCAR Cup Series Championship in 2015 and 2019.

He is survived by his wife, Samantha Busch, and their two children, son Brexton, 11, and daughter Lennix, 4.