The device struck photographer Darren Kidd and the steward was treated for shock.
The Irish FA could face UEFA action should the incident be included in the match delegate’s report.
Kidd told Sky Sports News HQ: “I have a ringing in my ears and a sore head. It hit me on the back of the neck where it burnt me and then burnt through my jacket burning me under the arm before exploding on the ground. My camera took the full force of it. I was lucky.”
The game between the top two sides in Group F finished goalless.