Karolyn Nunnallee still remembers that morning 25 years ago when her husband called to ask if she knew where to find their 10-year-old daughter Patty's dental records.
The authorities needed them, he told her, to identify Patty's body in the charred wreckage of what turned out to be the nation's worst-ever drunk driving crash.
"I still think about it, but not every day," Nunnallee says in a quiet voice choked with sadness. "That's a good thing, I guess. It means I'm healing."
The May 14, 1988, crash that claimed Patty's life – along with that of 26 other passengers (mostly children) in a school bus returning to Radcliff, Ky., from a church group amusement park outing – horrified the nation and paved the way for tougher drunk driving laws.
Now, to mark the 25th anniversary, one of the survivors, partnered with MADD (Mothers Against Drunk Driving), has put together Impact: After The Crash – a powerful, gritty documentary on the tragedy.
"I never wanted her to die in vain," says Nunnallee, a 62-year-old grandmother, who was so transformed by the tragedy that she later served as national president of MADD. "I don't want anyone to forget."
With that in mind, PEOPLE spoke with three others whose lives were forever changed by the crash.
HAROLD DENNIS: "I don't know why I survived and so many didn't"
"I couldn't breathe," says Dennis, who was 14 at the time. "I knew my life was over and felt that frantic feeling that can't be described unless you've gone through it."
In the chaos, time seemed to slow down and Dennis, hoping to escape through the front door, ran toward the front of the bus, already engulfed in flames. As each moment passed, the temperatures inside climbed, eventually hitting 2,000 degrees.
He tried to open a window in order to crawl out, but it wouldn't budge.
Seconds later, Dennis stumbled over a tangle of bodies as he tried to make it to the back of the bus, only realize that the tiny emergency exit was clogged with many of the other 66 passengers desperately trying to escape.
"Someone on the outside grabbed my arm, put their foot on the bumper and literally pulled me out," Dennis says. "I hit the asphalt and started running, even though I couldn't see anything because my eyes were swollen shut. I could hear the screams and the explosions."
Dennis, who suffered third-degree burns on 20 percent of his body, spent years undergoing multiple skin-graft surgeries. "Going through this," he says, "forced me to grow up and mature a lot faster."
He eventually threw himself into athletics and made headlines years later while playing wide receiver for the University of Kentucky football team.
Now 39, married and the father of three, Dennis – whose best friend died in the blaze – hopes the movie he produced about the tragedy will not only remind people about the dangers of driving drunk, "but how the choices we make can affect our lives and the lives of countless other people around us."
QUINTON HIGGINS: "I knew I was going to die"
Like Dennis, Higgins was pulled from the back of the burning bus with burns covering much of his body. "Doctors told my parents I had a 50-50 chance of living," he recalls.
After the accident as he lay in his hospital bed recuperating, he grappled with a jumble of feelings, made even more complicated by the fact that his alcoholic father had been involved in several drunk driving accidents.
This, he insists, was one of the reasons why he was able to eventually forgive Larry Mahoney, the driver who spent nearly 10 years (of a 17-year-sentence) in prison for the 27 deaths.
"One of my first thoughts when I woke up was, 'This could have been my dad,' " says Higgins. "That's how I was able to forgive Larry. I know he didn't wake up that morning saying he was going to kill 27 people."
Like Dennis, Higgins, who also lost his best friend in the blaze, has tried to use the trauma to transform the way people think about drunk driving. "When I tell kids my story," he says, "they always say to me, 'I'll never drink and drive.' So hopefully I'm helping to change some lives."
If nothing else, the tragedy has made Higgins much more obsessive about bus safety. "I'm definitely strict about safety on my bus, especially when it comes to blocking aisles and emergency exits," he says. "Sometimes the kids ask why I'm so serious about it. But once they hear what I went through, they understand."
LEE WILLIAMS: "I lost my wife, two little girls and all the memories I wanted to make"
Six hours later, he learned the awful truth.
"I'd lost all of them," he says. "Words can't even begin to describe the loneliness, hurt and complete emptiness that I felt."
Not long after their deaths, Williams, now 63, pulled all his family photographs off the walls of his home and packed them away in boxes.
At night, he would sit in the empty house alone, sometimes wandering into his daughters' bedrooms to stare at their Barbie dolls or their clothes still strewn across the floor, touching the items because he knew his daughters had.
"Some nights," he says, "I'd stay out all night driving around because I didn't want to go home."
Nine months after the crash, Williams got up the nerve to ask Dotty Pearman to eat lunch with him at a local restaurant. Pearman's husband, killed in the accident, had been the bus driver; her daughter Christy, a passenger on the bus, nearly died from the burns she received in the blaze.
"I didn't care what anyone thought," Williams recalls. "I just wanted to be with someone who had lost somebody, who knew what it was like to wake up in the middle of the night and know your spouse is no longer there."
Williams and Dotty, 59, married five months later and he went to work becoming a father to Dotty's three children. The couple now have 11 grandkids.
"I have a blessed life," says Williams, an associate pastor at the Radcliff First Assembly of God Church. "All this has made me slow down and appreciate what I have. When you lose one treasure and God gives you another, you do everything you can to take care of it."