Could be true but I've never heard of a fire cause be refrigerate refridgerant.
That's because in the US other non flammable refrigerants are used. The CFC (Chlorinated flourocarbon--AKA: Freon) refrigerants worked fine, but supposedly were making a hole in the ozone layer.
Other gasses which are volatile will work, including propane and butane, but are not used here in the States, precisely because of the fire danger.