(Update 2:15 p.m.)—Eight people who were at a Johns Hopkins administrative building in Keswick were hospitalized Monday after reporting trouble breathing.

At about 9 a.m., an ambulance responded to the South building at the location after one person complained of trouble breathing, Connor Scott, a spokesman for the Mayor's Office of Emergency Management, said during a press conference. Later, there were additional reports of 17 people struggling to breathe, eight of those individuals were taken to the hospital.

"At this point the city fire department has done monitoring and testing and found nothing," Scott said. "Again the cause of the illness of the 17 people is under investigation at this time."

The South building was initially evacuated, and those employees have been allowed to go home for the day. They were advised to call 911 if they feel sick and report it to their immediate supervisor.

A total of 1,050 of people work at the North and South buidlings at the complex.

Fire officials initially reported the cause of the incident was carbon monoxide exposure.

Stay with Patch for updates.