Police, fire and ambulance were called to level six of the Rutherford Building, which houses the chemistry department, just after 12.30pm, said fire communications shift manager Brent Dunn.
University spokesman John MacDonald said its' response to the incident had now been scaled back to a health and safety matter and the university will be monitoring the students' progress this afternoon.
He added that as a result of coverage of the incident the university has been receiving inquiries from friends and family of staff and students.
"The university is advising staff and students to let friends and family know they are safe if they think they may be concerned."