Hundreds made the most of the Whanganui Fire Brigade's electric blanket testing initiative with 724 getting tested.
Of those 43, or 0.5 per cent, failed.
"Electric blankets can be a fire risk if they aren't not stored properly, are used unsafely or there are signs of wear and tear," fire risk management officer Bob Wills-Rawlings said.
"It was great to have such a big response to the event and see so many people aware of the fire risks and wanting to check their electric blankets are safe. It's especially important coming into winter when more people use their electric blankets as the nights get cooler."
Two testing tables were set up with electricians and four on duty firefighters, carrying out visual checks and a portable appliance test on the electric blankets.