Lucy,
There are programs specifically targetted towards the fire-starting behaviors. They are normally through the local fire marshalls office or the nearest big town office.
There are also home video and instruction packets for parents of firestarters that live too far from any program to attend.
Here is a link to one program
http://www.springsgov.com/Page.asp?NavID=1104
As to the question, fire-starting has an underlying cause. If the underlying cause can be treated, and the behavior stopped. Of course the child should be available for adoption.
There are varying degrees of the intensity of the fire-starting behaviors though. Just like the list for the difference between a sexually reactive child and a sexual perpetrator.....
there is a difference between children who start fires and plan them out days in advance with the intent to destroy and the child that acts out of "I am (hurting, angry, confused etc) and stumbles across the matches and sets a fire.
I have met some very "successful in life" adults that were juvenile firestarters. So it can be treated.
We did decide to disrupt our adotpive placement, but not just because of the firestarting.
The scarry part of his fire-starting was ----the planning involved to start the fires, the intent days beforehand, the having another child bring matches to school, hiding the matches in the hem of the pants so that I couldn't find them. The intensity of desire to start a fire at all costs, his almost setting himself purposely on fire (lighting the blanket he was under on fire), was more than I felt safe for the other children in home.