Up to 40 university students had to be evacuated from an accommodation block in Preston during the night after smoke triggered an alarm.
Firefighters raced to the iQ Kopa block in Moor Lane to deal with the incident in one of the apartments at around 2.30am on Friday.
And later a brigade spokesman praised the on-site security team for taking swift action to get the University of Central Lancashire students out.
“The staff did a great job - all the occupants were out when we arrived,” said watch manager Dave Robinson.
“It turned out not to be a serious incident, but they weren’t to know.
“An immersion heater in one of the flats had over-heated and produced some smoke which activated an alarm. We just isolated the heater and checked things out before the students were allowed back in.”