The Football Association are investigating the evacuation incident at Derby County's Pride Park on Friday night, WalesOnline has learned.
The stadium was evacuated just before kick-off ahead of Cardiff City's game against the Rams.
It is believed that flares set off in the away end at the stadium prompted the action, which saw every member of staff leave the arena.
The Sun are reporting that it is the first time flares have caused a whole stadium to be evacuated in England.
A message read over the address system said: "Attention please, this is an emergency. Please leave the stadium by the nearest available exit."
The FA confirmed to WalesOnline they were aware of the incident and were investigating.
The game between the two Championship sides finished 1-1, with the Bluebirds' Robert Glatzel scoring his first goal for the club via the penalty spot.
