BEN CLASSON/Herald photo

A University of Wisconsin building was evacuated Friday after several gallons of chemicals were spilled in a 12th-floor laboratory.

UW professor of materials science and engineering John Perepezko, responsible for the lab in the Engineering Research Building, said some of his post-doctoral students were etching metal samples, a process that requires a small amount of acid.

When the student returned a bottle of reagents to the cabinet, one of the glasses was broken and some of the chemicals escaped. The reaction produced fumes that spread mostly in the room and parts of the floor.

Though the initial Madison Fire Department report claims passersby heard a popping noise on the 12th floor, Perepezko said there was no explosion involved, but only glass cracking.

At 3:48 p.m., MFD arrived at the scene and evacuated the building. Minutes later, the call was upgraded to a Hazardous Material call, and the UW Environment, Health and Safety Department also arrived at the scene.

Upon arrival, UW Safety used a sodium bicarbonate to neutralize the acid and make it harmless, according to Perepezko. No one was injured.

?They did the right thing. The fire alarm was pulled and the building was evacuated, which is standard procedure for a thing like that,? said Andy Garcia-Rivera, UW Safety director.

Though the cause for fumes remains unclear, Garcia-Rivera said UW Safety would meet with chemists today to figure out what exactly caused the incident.

?What we believe may have happened could?ve been that somewhere along the line somebody could?ve poured an incompatible chemical into one of the bottles that were being stored there,? he added.

According to Perepezko, the reagents stored in the cabinet were acetic acid, ammonium hydroxide and nitric acid ? concentrated chemicals available for experimental purposes.

The professor said the incident was a ?small event in retrospect,? adding he was overwhelmed by the response of UW Safety and MFD. He added the building was evacuated ?to remain on the safe side.?

?I don?t mean to minimize anything, but it wasn?t a major event that caused anybody harm,? Perepezko said. ?Nobody even had breathing difficulties because we acted quickly. The safety mounted a full response, which is nice to know, but in this particular instance, it was more than necessary.?