Washington, June 9 (IANS): Up to 66 laboratories received samples of active anthrax by mistake and are located in 19 different US states, the District of Columbia, Australia, South Korea and Canada, according to the Pentagon.

The last estimate from the US Department of Defense on June 3, placed samples sent to 51 facilities in 17 states.

The two new states to have joined the list include Pennsylvania and Rhode Island, which also received samples from the US army facilities of Dugway Proving Ground in Utah, Efe news agency reported.

Steve Warren, the spokesperson for the Department of Defense, said that 31 people who have been exposed to active anthrax are receiving preventive treatments, though no one has been infected and there is no risk to the general public.

The Pentagon, which has opened an investigation into what happened, mistakenly distributed samples of this bacillus to the laboratories thinking they were inactive and harmless.

Despite the anthrax being active, the possibility of infection is very low, since the vials did not have a high concentration, were sealed and were in liquid form, making it almost impossible to get infected by inhalation.

The investigation, the results of which are expected by the end of June, will review more than 400 submissions of anthrax throughout the country that were classified as inactive, something that is now under question.

The Center for Disease Control and Prevention in Atlanta is also collaborating in the investigation.