Frozen vials labeled “Smallpox” were recently discovered by a laboratory worker at a Pennsylvania facility that conducts vaccine research, federal officials said.

According to Centers for Disease Control and Prevention (CDC), the vials came out of a freezer that was being cleared by a worker at an unspecified location.

“CDC, its administration partners, and law enforcement are investigating the matter and the vials’ contents appear intact,” a CDC spokesperson told The Associated Press.

“The laboratory worker who discovered the vials was wearing gloves and a face mask. There is no indication that anyone has been exposed to the small number of frozen vials.”

The deadly smallpox disease was eradicated worldwide in 1980.

The variola virus caused smallpox to plague the world over centuries, killing nearly one third of its victims.

The World Health Organization has designated two locations in the world as the variolavirus research centers. One is in Atlanta, and the other one in Russia.

According to the CDC, smallpox research is centered on the development of drugs, vaccines and diagnostic tools that protect against this infectious disease.

With Post wires