– Multiple floors and corridors inside the Pentagon have been locked down and others are being evacuated due to a “hazardous materials incident,” three sources familiar and the local fire department said.Pentagon spokesman Sean Parnell confirmed Thursday that systems within the Pentagon “have detected an air quality issue necessitating precautionary measures until we determine its significance.”“The Department is executing standard protection protocols, including a shelter-in-place order for the affected area,” Parnell said. “Response teams are in place and ready to support building occupants.”

The Pentagon Force Protection Agency’s hazardous materials response team is responding to the incident with the assistance of the Arlington County Fire Department, according to the department spokesperson Capt. Jamie Jill. A post on social media from the Arlington Fire & EMS said Arlington County Fire Department Hazardous Materials Team is operating at the Pentagon “during a hazardous materials incident.” A message sent by the Pentagon’s security team said an “air quality issue” had been detected and additional testing is needed.

“This additional testing could take one to two hours. Response teams are in place and ready to support building occupants if necessary. You may observe response personnel from multiple agencies and precautionary measures taking place in the center courtyard. Please do not interpret these activities,” the message said.Floors two through five in corridors four through seven of the sprawling Pentagon complex have been locked down, two of the sources said. The third source told CNN that police in the building are wearing gas masks and full chemical protective gear.