CDC microbiologists suiting up to enter a BSL-4 lab, the agency's highest-security biosafety lab. The scientist on the left is attaching his air hose, which supplies filtered air and maintains positive air pressure inside his orange suit. (James Gathany)

The Centers for Disease Control and Prevention has temporarily suspended work at its most secure biosafety lab that handles dangerous pathogens because air hoses that are part of the required full-body protective suits worn by lab workers were not certified for breathable air, officials said Friday.

About 100 employees have worked in the labs, at CDC’s Atlanta headquarters, since the air hoses were introduced in 2008. There is no evidence that any of the employees were exposed to infectious agents or to hazardous material from breathing air through the hoses, said Stephan Monroe, CDC’s associate director for laboratory science and safety.

“There have been no reports of acute health effects during the entire time” the hoses have been in use in the labs, Monroe said.

The problem was discovered during a routine inventory check Monday, and work at the labs was immediately suspended out of an abundance of caution, he said. The three affected labs are part of CDC’s highest-security biosafety lab complex, known as BSL-4, where researchers work on some of the world’s most dangerous pathogens, including Ebola and Marburg viruses.

Workers in the labs must wear specially designed protective suits and may disconnect and reconnect to several air hoses while they are working inside the lab and when they go through a decontamination process to exit. The hoses are attached to an air supply in the ceiling.

Monroe said the agency’s swift response reflects how the culture of safety has changed at the agency, which experienced a series of incidents in 2014 involving the mishandling of dangerous pathogens, including Ebola, anthrax and botulism bacteria, at its labs.

CDC is testing the air from the hoses to determine whether it meets federal standards for breathable air. Officials held an informational meeting with employees working in the labs earlier this week, he said. About 180 hoses need to be replaced. Some of the equipment is expected to arrive next week and will be installed before work in the labs resumes.

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