But the Department of Public Safety and the Department of Environment, Health and Safety have responded to about 20 emergency calls on campus regarding suspicious mail in the last week.
In every case, the DPS officers determined there was no credible threat.
University Mail Services, the sole recipient of all University mail, said regardless of the precautions it takes, its system is not foolproof.
"We are doing our best to screen and watch for suspicious packages, but it is incumbent on faculty and staff to be alert," said Tommy Brickhouse, manager of University Mail Services.
EHS Director Peter Reinhardt said the reports of suspicious mail were made by faculty, staff and students.
The deans' offices at the College of Arts and Sciences and the School of Medicine each received two of the 20 suspicious pieces of mail last Wednesday.
Reinhardt said people are being cautious about the mail they receive in light of the recent anthrax scares.
"We are cautious because we never know when it may be a credible threat," Reinhardt said.
University Mail Services staff are also being careful to look for "red flags" when manually sorting mail, Brickhouse said.