A suspicious smell prompted a brief evacuation at North Dakota State University on Monday, Feb. 20. Fire crews responded to reports of a natural gas odor about 2:30 p.m. at the NDSU library. They cleared everyone out of the building as a precaution. Firefighters soon discovered the odor was actually sewer smell. They say both dried out sewer traps and natural gas smell like rotten eggs. "About this time of the year, we start getting a few of these where it sat all winter and no water running inside of the trap, so they dry out," said Battalion Chief Lee Soeth of the Fargo Fire Department. One person complaining of dizziness was checked and cleared by paramedics.