Centers for Disease Control (CDC) microbiologists are suiting up in order to access the interior of the organization’s Biosafety Level-4 (BSL-4) laboratory in Atlanta, Georgia, U.S. in 2007. Courtesy James Gathany/CDC/Handout via REUTERS

Last Friday, ( 17th february 217) The U.S. Centers for Disease Control and Prevention has closed down its highest security biosafety laboratories after discovering that hoses that supply air to scientists wearing special protective suits were never approved for that use.

Stephan Monroe, associate director for laboratory science and safety at the CDC said he was confident scientists were not exposed to pathogens because the air they breathed passed through HEPA filters. The suits they wear also use positive air pressure to prevent pathogens from entering the suit.

CDC is now conducting safety tests to determine whether the scientists might have been exposed to harmful chemicals that passed through the air hoses.

The problem stems from the original construction in 2005 of the Biosafety Level-4 laboratories, in which scientists handle the most dangerous biological agents.

CDC officials learned about the problem when they ordered replacement hoses, and were told by the manufacturer that they were not certified for breathing air.  

However Monroe said he was confident scientists ( former and current ones)  were not exposed to pathogens because the air they breathed passed through HEPA filters.

Replacement tubing have been now ordered that it is expected to be installed this weekend and plans to bring the labs back online next week.