Checks of the postal facility did not begin until Friday and checks of workers did not start until Sunday, according to Deborah Willhite, with the U.S. Postal Service.

CNN: Postal workers angry over response

"We followed the advice of the CDC and other public health officials who advised us that until there was an evidence chain that indicated that there was anthrax present in the facility, that it was not necessary to test our workers, " Willhite said.

CNN: Postal workers angry over response