A lab fire at the Wisconsin Energy Institute at UW-Madison prompted an evacuation on Tuesday.
Madison Fire Department crews responded to a fire alarm at around 1:20 p.m., though no smoke or fire could be seen when they arrived.
Crews were then told by a building manager that there was an active fire in an autoclave lab room. Firefighters were able to put out the fire, which was coming from an oven in the room.
An investigation showed that non-oven-safe plastic items used for cleaning the autoclave had accidentally been left in the oven.
A lab worker noticed smoke coming from the room, opened the oven, and the incoming oxygen caused the fire to flare up. After failing to put out the fire with a dry chemical extinguisher, the fire alarm was pulled and the building was evacuated.