Campbellsville Police Chief Tim Hazlette said the power line was never touched Thursday morning, but it carried such a high voltage that it was able to energize the ladder truck, shocking the firefighters.
The two in the bucket were at a hospital burn unit early Friday. One was in critical condition and the other was in fair condition, the hospital said. The other firefighters were treated and released.
The firefighters had just taken part in the ice bucket challenge that helps raise money for ALS research. They dumped water on the Campbellsville University's marching band, but most of the students had already left the area and no students were hurt.
University nursing student Julie Smith said she was nearby and spoke to a couple of friends who saw the firefighters being shocked and said "they are taking it really hard."
"It's tragic, I feel for all the band members who were still there when it happened, that they had to see that," Smith said. Smith later led a prayer vigil with about 100 people on the campus Thursday night.
Taylor County Judge-Executive Eddie Rogers said Friday that the community was still reeling from the accident.
"We never know when something like this is going to happen," he said. "Everybody's heartbroken over it."
The ice bucket challenge has been sweeping social media websites. The ALS Association said it has raised more than $41 million.
Police said Capt. Tony Grider, 41, and Simon A. Quinn, 22, were in the fire truck bucket. Grider, a 16-year veteran of the department, was in critical condition at the University of Louisville Medical Center Burn Unit. Quinn, a part-time firefighter, was listed in fair condition there.
Campbellsville University, a private college, is a Christian institution that has about 3,600 students, according to its website. It is about 65 miles south of Louisville.
Elise Amendola / AP