The fire chief in North Sydney has had enough with arsonists in the town after several firefighters were injured while responding to calls for help.

Lloyd MacIntosh says the department has responded to 19 fires since March. Of those, 13 were caused by arson.

"One of these apartment buildings had a family of five people in it," MacIntosh said. "They were in that building when that building was set on fire. That's not right by any way, shape or form."

In another situation, two teenagers were charged with setting fire to an abandoned house. MacIntosh said several volunteer firefighters were nearly struck by a falling brick wall while responding to that fire.

"We've had injuries to firefighters," MacIntosh said. "We've had firefighters taken to the hospital with bumps and bruises, chest pains, strained muscles, for a variety of reasons. We've had roofs collapse on them, walls fall in."

One of the injured was Elizabeth LaFosse, who was standing on the top of two flights of stairs in a home when the ceiling collapsed.

"I didn't realize the landing was so short," she said. LaFosse fell down the stairs, leaving her badly bruised and with a knee injury.

MacIntosh said some fires are set by thrill-seeking kids, some are retribution, and some are set to collect insurance. But he said no reason is good enough to justify starting any fire. He's pleading with people to stop before someone is killed.