Part of the campus at Bishop Grosseteste University was evacuated after a suspicious letter was found.
Lincolnshire Police said a suspicious letter was delivered to the campus.
A cordon was set up around the Robert Hardy Building on the university campus in North Lincoln.
An EOD (explosive ordnance disposal) team arrived at the scene and investigated the contents just after 1.20pm.
The cordon was lifted at around 1.35pm.
There were also a number of primary school children on campus taking part in a sports tournament.
The Hardy and BG Futures buildings were evacuated.
A spokesperson for the university said at the time: “Bishop Grosseteste University are working with Lincolnshire Police to investigate a suspicious package sent to campus this morning.
“At this time our main concern is the safety of our staff and students and therefore we have evacuated our Hardy and BG Futures buildings along with our Sports & Fitness Centre.
“The rest of campus is currently unaffected.
“Thank you to all our students and staff for reacting swiftly to this incident. We will update you as soon as more information is available.”