Three construction workers at Thurston Hall were transported to local hospitals Wednesday morning with serious but non-life threatening injuries after concrete sealant fumes reportedly caused them to lose consciousness in the building.

D.C. Fire and Emergency Medical Services said first responders responded to a call reporting unconscious workers in a below-ground window well, and a tweet from the department states the workers inhaled concrete solvent in an enclosed space. The workers are said to have serious non-life threatening injuries. University officials began renovating Thurston Hall in May of 2020, and the building is scheduled to house more than 800 freshmen this fall.

Vito Maggiolo, FEMS’ public information officer, said a fourth worker was evaluated by EMS after they were exposed to the fumes, but declined further medical treatment.

The GW community received a GW Alert detailing police and medical activity near Thurston Hall from the University’s emergency alert system at about 10 a.m. before an all-clear statement was issued around 11 a.m.

University spokesperson Tim Pierce did not immediately return a request for comment.