Brockton Fire Lieutenant Edward Williams said Friday that the Thursday night fire was ignited when the children bounced up and down on two mattresses that were against a wall where a cell phone charger was plugged. He said the back-and-forth motion of the mattresses abraded a transformer for a cell phone charger which caused sparks or a short circuit.
Williams said the fire flared up just after 8 p.m. Thursday, causing $150,000 in damages to one building and $50,000 to a nearby apartment building.
Two firefighters suffered puncture wounds and cuts, but neither was hospitalized.
No other injuries were reported.