My son at age 4 and 5 played with matches whenever he got a chance (like when I was putting my little one down for a nap, he would scale the cupboards and frisk them searching for matches). I tried talking sternly with him and explaining the consequences, not to any avail. He still admitted to lighting matches (until I was smart enough to not have ANY at the house), then dropping them on our hardwood floors because he got scared while I was laying the baby down. Sigh.
I tried taking him to the fire station. They referred me to the central office. I asked if he could see a video or something, instead the put us in two different rooms and grilled me and he individually on parenting styles. They asked him if he ever got spanked with a belt. What the heck does that have to do with fires and little boys? I should have stopped the whole thing, but I didn't know what to do. AFter feeling totally let down bythe fire department, I removed all matches from the house. Did that stop my son? NOOOOOO! He learned that people throw match books down on the ground particularly in grocery store parking lots, and made it a point to look for them. For his effort, he usually found one to three matches per book.
Since limiting access didn't seem to work, I decided to try to channel his fire energy into something positive...learning to build fires from scratch using bow and hand drills. Its now a year later, and venting his energies by building fires from scratch with him every week have made a huge difference. Plus, if we ever need to have a fire made in a survival situation, he should be an expert by the time he is 8!
I don't know if this will help, but it worked for us.