No one is injured after an apartment unit catches fire last night in Mankato. Firefighters were called to Glenwood Terrace Apartments around 6:45 last night on a report of a grease fire on the third floor of one of the buildings. Witnesses say a resident was making popcorn on the stovetop when the fire began. They say water was used to put out that fire, which caused it to spread. Firefighters were able to contain the fire to the single apartment unit. No injuries were reported. Details on the extent of damage have not been released.