The scene of the fire and evidence of the firework
A firework caused a vegetation fire in a field off the N7, Dublin Fire Brigade said.
The fire fighters were called to the blaze in the Clondalkin area.
DFB said: "We've extinguished a straw fire in Clondalkin this afternoon.
"Unfortunately fireworks were found at the site of the fire."
The firefighters warned people not to light open fires or BBQs in the countryside as vegetation is dry and can easily ignite.