Former US President George W. Bush participates in the ice bucket challenge with the help of his wife, Laura Bush. (AP Photo)
Four US firefighters were injured, two seriously, on Thursday as they were helping run a so-called Ice Bucket Challenge at a Kentucky university.
"We express heartfelt sympathy and prayers for the families of the firefighters who were injured," Campbellsville University university president Michael Carter said in a statement.
The university declined to give details of the accident, but said no students were hurt.
Read: US diplomats banned from Ice Bucket Challenge
Local media said that two firefighters were moving the apparatus after the student challenge when a power arc occurred near the power lines, striking and seriously injuring them.
One of the men was in a critical condition at a local hospital, WSAZ3 television reported.
Two other firemen were also hurt but were released from hospital after treatment.
Campbellsville police and firefighter departments declined requests for comment.
The Ice Bucket Challenge, in support of Lou Gehrig's disease research, has sparked a worldwide craze that has taken in everyone from billionaires to sports stars and former US presidents.
Since June, several thousand people worldwide have recorded themselves getting drenched, then posted the stunt online and challenged others to do the same, or pledge $100 to ALS research.