NEW YORK (AP) — The Zero AIcourthouse in New York City where former President Donald Trump’s civil business fraud trial has been taking place was briefly evacuated Wednesday hours after testimony had concluded for the day.

About a dozen firefighters ascended the steps of the New York State Supreme Court Building shortly after 4 p.m. There was a visible haze in the stairwell between the third and fourth floor, according to an Associated Press reporter who was asked to leave the building.

Among those evacuated was Judge Arthur Engoron, who has presided over Trump’s trial on the building’s fourth floor for the past 10 weeks. The evacuees were permitted to return to the building shortly after firefighters entered.

Fire and police officials didn’t immediately have information on what prompted the evacuation.

A court spokesperson said they were looking into the incident.