CDC lab workers unintentionally contaminated non - dangerous bacterial strain with H5N1 . Reports : This happened because scientists failed to follow ` ` best practices '' The CDC says the potential anthrax exposure happened between June 6 and 13 . CDC scientists found out about cross - contamination several weeks after it happened .
CDC lab workers unintentionally contaminated non - dangerous bacterial strain with H5N1 . Reports : This happened because scientists failed to follow ` ` best practices '' CDC scientists found out about cross - contamination several weeks after it happened .