This article was reproduced with the kind permission
of the British Broadcasting Corporation
8 November 2007, 09:59 GMT
Cathy and Luke Frankland were watching television downstairs on Tuesday night when they heard glass breaking upstairs - where their two sons were sleeping.
The firework went into the room next door to where the toddlers were in bed.
East Sussex fire service urged people to attend public displays, and to hold private displays in a "safe area".
Thank goodness it wasn't the boys' bedroom
Mr Frankland said: "Once I first set eyes on the fire, I tried to subdue it, but realised I was fighting a bit of a losing battle - then my main concern was to get everybody out the house."
He said the extent of the damage showed he had made the right decision.
Mrs Frankland said: "This was obviously somebody who didn't know what they were doing - whether it was a private party or whether it was people mucking about, we don't know.
"But this is the trouble they've caused. This is the damage they've caused.
"And thank goodness we weren't in the room at the time, thank goodness it wasn't the boys' bedroom, because if it had been, I don't like to think about what would have happened."
Fire teams believe the incident was an accident.
Spokesman Andrew Gausden said: "We would recommend you attend organised displays but obviously fireworks are available for private displays.
"If you are going to have a private display, please ensure you do it in a safe area and in a safe manner and bear in mind the associated risks of using fireworks."