The firefighters were taking part in extreme version of the challenge that helps raise money for ALS research by dumping water on members of the Campbellsville University's marching band from the top of a bucket ladder.
Two firefighters were in the bucket and two were on the main part of the truck when it got too close to the high-voltage wires.
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. One was in critical condition and the other was stable, Campbellsville Police Chief Tim Hazlette said. The other firefighters were treated and released.
None of the band members who participated and students who had gathered to watch were hurt.
“A number of our students, of course, the entire marching band, witnessed the event and so we’re concerned about them and the tragedy of this accident,” university president Michael Carter told WHAS-TV.
Power was knocked out for about an hour to 4,500 customers, including the school, said Natasha Collins, a spokeswoman for Kentucky Utilities, which owns the line. The Public Service Commission will investigate whether the line had the correct clearance from the ground, trees and structures, said Andrew Melnykovich, a spokesman for the state Public Service Commission.
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.