CHICAGO (CBS) – After several teens were hurt during a fire, firefighters want the public to know the dangers of pouring liquid fuel on a fire.

Glendale Firefighters demonstrated by pouring liquid fuel on a fire Wednesday. Once the liquid fuel was poured, you could hear balloons popping where people would be sitting nearby. Anyone in the chairs around the fire would have been badly burned.

Firefighters say that is what happened Saturday night in Glendale Heights when someone poured gas on a backyard fire pit, injuring 12 teens.

Greg Ostrand was one of the first firefighters to arrive.

“A lot of burned kids walking around in shock. Had that million mile stare, walking around not really knowing what was going on when we pulled up,” said Ostrand.

Officials say 5,000 Americans are burned by flames from barbeque grills and fire pits.