A woman has been injured in a fridge explosion in a college canteen.
Fire chiefs said a refrigeration unit blew up on the first floor of the Tower Building in the North West Regional College in Derry at about 8.40am.
There was no fire.
The Northern Ireland Fire and Rescue Service (NIFRS) said gas monitors were used to asses whether there had been a leak in the canteen, while firefighters isolated the power and ventilated the area.
An investigation was launched by the Health and Safety Executive and the woman was treated in hospital.
Meanwhile, five people escaped injury in two house fires.
In one suspected arson attack, old furniture was piled up against the front door of a house in Drumard Park, Derry city, and set on fire.
Detectives investigating the blaze said the alarm was raised at about 3am.
Four people who were in the house at the time were able to escape through the back door after a smoke alarm went off.
The front of the home was badly damaged.
Detective Sergeant Brian Reid said: “It appears some old furniture was deliberately placed against the front door of the property and set alight, blocking the doorway.”
“A motive for the incident has not yet been established and we are keen to hear from anyone with information regarding this crime.”
Meanwhile, on the Coast Road in Larne, Co Antrim, a woman escaped from a house after a smoke alarm alerted her to a fire.
Firefighters received a call at 2.19am after the blaze broke out and described it as severe.
A spokesman for the NIFRS said the woman was out of the house by the time fire crews arrived.
The blaze gutted her two-storey detached home and also involved the oil tank.
The exterior of a second property was also damaged after the fire spread and set fire to a second oil tank.
Two appliances from Larne, another two from Ballyclare and an aerial appliance from Knock Fire Station in east Belfast attended.
“The cause of the fire is under investigation,” a spokesman for the NIFRS said.