About 75 Atlanta-based workers for the Centers for Disease Control and Prevention may have been unintentionally exposed to anthrax, the agency said Thursday.
They are being monitored or provided antibiotics.
"Based on most of the potential exposure scenarios, the risk of infection is very low," the agency said in a statement.
"CDC believes that other CDC staff, family members, and the general public are not at risk of exposure and do not need to take any protective action."
Early reports show that a lab did not adequately inactivate samples, which were then moved and used for experimentation in three laboratories not equipped to handle live Bacillus anthracis, or anthrax.
Believing the samples were inactivated, workers in those labs did not don adequate protective equipment, the CDC said.
The unintentional exposure was discovered June 13.
Sometime between then and June 6, procedures in two of the three labs may have aerosolized the spores, the CDC said. Hallway and lab areas were decontaminated.
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