Two Kentucky firefighters were seriously injured when the fire truck's ladder got too close to a power line as they helped college students take part in an ice bucket challenge.
Campbellsville Police Chief Tim Hazlette said that one of the firefighters is in critical condition and the other is stable.
They were in the truck's bucket as it was being lowered when they received electric shocks.
He says two other firefighters on the main part of the truck were also shocked. They have been treated and released.
Campbellsville University asked the local fire department to help spray its Tiger marching band with cold water to raise awareness for ALS.
No students were hurt.
Meanwhile President Barack Obama declined to take part in the ice bucket challenge that is sweeping America to raise money and awareness for amyotrophic lateral sclerosis, or ALS.
The challenge asks people to post videos of themselves being doused with cold water and publicly call on others to do the same within 24 hours, or donate money to the ALS Association. It has raised more than 40 million dollars (£24 million).
The disorder, also called Lou Gehrig's disease, attacks nerve cells and can lead to complete paralysis and death. Average life expectancy is two to five years after diagnosis, according to the ALS Association.
The challenge calls on people to post videos on social media of themselves dumping a bucket of ice water on their heads - or having someone else handle the chilly chore.
Well-known participants include former President George W Bush Ethel Kennedy. The 86-year-old Kennedy family matriarch challenged Mr Obama after recently dousing herself at her family's Massachusetts estate, knowing that the president would be nearby on vacation.
Mr Obama participated financially by donating an undisclosed sum, the White House said.
"This is all about awareness. We appreciate him donating to the cause," ALS Association spokeswoman Carrie Munk said.
The president is not the only US government official who is unlikely to participate.
The US State Department has banned participation by US ambassadors and other high-profile foreign service officers.
Department lawyers say participation would violate ethics rules barring officials from using public office for private gain "no matter how worthy the cause," according to an unclassified cable sent earlier this week.