It has been 24 years since Minnesota Viking Korey Stringer collapsed on the field at training camp — a shocking event that eventually reshaped the NFL.

His family says he died from exertional heat stroke, and experts say it didn't have to happen.

"We met at Ohio State. I was not impressed at all," said Kelci Stringer, the wife of Korey Stringer.

But eventually, Kelci Stringer started dating her future husband, an up-and-comer in the world of professional football.

"People are asking for his autograph, and I'm like, 'He's no celebrity! What's happening? It's Korey!'" Kelci Stringer said.

Korey Stringer, an All-American lineman, was drafted in the first round by the Minnesota Vikings in 1995.

"We got married on June 10, 1998, at Hennepin County Courthouse on a Saturday morning," Kelci Stringer said. "We have one picture. We didn't have a camera, we didn't have anything. And the court officer asked, they had polaroids, then and he asked if we wanted a photo, we were like, 'Yeah, please.'"

In Minnesota, they'd welcome their son, Kodie.

"We were just very happy together in our life with Kodie," Kelci Stringer said. "And of course, the team was very good during that time, so that helped."

Fast forward to July 31, 2001.

"That was his seventh season. It was a shorter training camp," Kelci Stringer said.

While he went off to camp in Mankato, Kelci Stringer took their son to visit family in Atlanta.

"I got a phone call from one of his teammate's wife and it was just so matter-of-fact, and she's like, 'Well what's going on with Korey?' And I'm like, 'What are you talking about?'" Kelci Stringer said. "She's like, 'His lungs collapsed and he's in a coma.'"

Kelci Stringer was shocked and confused.

"Honestly, he was at the peak of his career and the best shape of his life," she said.

She wanted to make it to Minnesota, but there was only one flight there that day and she was going to miss it.

"I'll forever be indebted to Randy Moss, who was a very good friend of Korey's as well. He was like, 'Hey I found a plane for you.' And it was this medic plane," said Kelci Stringer. "We flew out to Minnesota that night."

Kelci Stringer arrived at the hospital 15 hours after Korey Stringer collapsed.

"I get in the elevator. Daunte Culpepper, at the time, gets on the elevator and I'm like, 'Pepp, how is he?' And he's like, 'He's OK,' but he's crying," said Kelci Stringer. "I'm thinking, 'Well, maybe he's not as good as they're saying.' I get off the elevator and Coach Tice just looked at me. He puts his hands on my shoulders and he's like, 'We lost him.' He had died an hour before I got there. I just felt that I let him down by not being there. He deserved that."

Doug Casa, a professor at the University of Connecticut, was an expert witness for the Stringer family during their decade-long litigation with many entities, including the NFL, over Korey Stringer's death. He eventually became the CEO of the Korey Stringer Institute.

"Monday was the first day of practices. It was July 30, and they had two-a-day practice. On that first day, it was super hot. Full gear and made no modifications even though it was brutal," Casa said. "It was near, like, 100 degrees — just the regular temperature. The morning of July 31, which was a Tuesday, they had another full practice in extreme heat. He suffered the heat stroke at the end of that Tuesday morning practice."

Casa says when Korey Stringer went down, they brought him into an air-conditioned trailer, but failed to aggressively cool his body — the gold standard for treatment.

"They didn't do the aggressive cooling," said Casa. "Exertional heat stroke has been 100% survivable if someone's temp gets under 104 within 30 mins of presentation. When he got to the hospital, it was in the 108s still. That means he was even hotter when he went down."

"What I found out was there was just really basic protocols that could have been done," Kelci Stringer said. "I mean, it just simply came out that his death was preventable. They had plenty of ice and water, and a tub is $150 at Tractor Supply. It's not a difficult intervention. That's why we lost Korey."

From tragedy came action as Kelci Stringer vowed to do something in Korey Stringer's name.

"Korey was a very giving, very selfless person. Only thing I tried to do from then on is to mirror him," said Kelci Stringer.

In the wake of Korey Stringer's death, his wife founded the Korey Stringer Institute at the University of Connecticut in 2010. It does cutting-edge research, education and advocacy work to protect athletes, laborers and military members.