Cardinal Newman College on Larkhill Road in Preston has been closed today due to a potential gas leak.
Students have been advised to stay at home and the building has been evacuated following reports of a smell of gas at the sixth form college this morning (2 December).
Staff from Cardinal Newman alerted the National Grid of a potential problem at around 8am this morning.
Cardinal Newman College's Principal, Nick Burnham said: "This morning at 8.10 am the college was made aware of a potential gas leak which was detected across the St Wilfred's and St Bedes buildings.
"The buildings were evacuated and all appropriate agencies called immediately. As student and staff safety is paramount the decision was made to close the college.
"The college remains closed and National Grid are currently on scene."
The incident has affected around 3,500 pupils and 270 staff who were due to attend the sixth form college today.
Cardinal Newman student Ashley Woodall, 18, said: "I went in this morning and had to find out from other students that it was closed because Newman put it on their Twitter and web page but didn't notify us directly.
"I got there and there were a lot of students waiting to go in and getting angry as they had to travel but the teachers were telling them to wait until they had more information.
"I'm not upset by the day off, but I am worried that I will fall behind in my coursework so I'll be spending today revising my subjects."
The college is expected to remain closed for the rest of the day.