This post was updated Oct. 20 at 11:34 p.m.

A fire broke out in Young Hall Oct. 10, causing a partial shutdown of the building’s third floor.

The fire began on the second-floor foyer of Young Hall, according to an emailed statement from a spokesperson for UCLA. The fire – caused by an electrical fault – distributed potentially carcinogenic nanoparticles, causing the closure of the west third-floor corridor in the building, according to a sign in the building.

Janette Kropat, the facilities and operations manager of the Department of Chemistry and Biochemistry, said a custodian was vacuuming the rubber mat near the entrance to the right of Young Hall CS24 when it sparked and caught fire.

Kropat added that the custodian could not put the fire out with a fire extinguisher because the vacuum contained lithium-ion batteries and instead let the mat burn until the fire dwindled.

The fire did not spread beyond the mat, but the smoke it produced covered the third floor in soot, she said.

“There was a five-foot flame coming out (the vacuum) and that filled the corridor with black smoke and penetrated everything,” she said. “The custodian tried to clean it up, but it’s a big job.”

Nobody was injured by the incident, and classes remain in session, Kropat said.

She added that the Office of Environment, Health & Safety blocked off the corridor to facilitate cleanup and prevent potentially harmful particles found in the mat and vacuum from being disturbed and aerosolized.

“The Los Angeles Fire Department removed the melted vacuum cleaner to the courtyard outside of the building,” UCLA Media Relations said in an emailed statement. “Cleanup of the soot in the affected areas was initiated and that area has been temporarily closed but is expected to open sometime next week.”