A pair of NFL helmets were severely damaged Monday in an explosive head-on collision during a broadcast of ABC's Monday Night Football. 'We are still reconstructing the incident, searching for any clue as to what could have gone wrong,' Monday Night Football play-by-play announcer Al Michaels said of the catastrophe, which occurred minutes before kickoff and was seen live by an estimated 17 million television viewers. 'The helmets were securely chained to their respective space-platforms by four safety tethers, and there was no reason to suspect they would be able to break free.' Witnesses said the chained helmets, which directly faced each other on their platforms, seemed increasingly angry and agitated in the moments leading up to the disaster. 