Shipping giant FedEx no longer is willing to transport packages containing research specimens of potential bioterror pathogens in the wake of high-profile safety mistakes by an Army lab that unknowingly shipped live anthrax for years, according to a letter the company sent to federal regulators and obtained by USA TODAY.

FedEx’s refusal to transport these kinds of specimens is drawing concern among officials at major laboratories, who say it was the primary way they sent and received critical samples used to diagnose diseases and for the development of vaccines, treatments, tests and detection equipment. Neither UPS nor the U.S. Postal Service will transport the specimens.

“It potentially is a devastating blow,” said James Le Duc, director of the Galveston National Laboratory in Texas, a major high-containment research facility that has two to three shipments a month. Le Duc said much of infectious-disease research involves pathogens found in the wild in other parts of the world, which requires the shipment of specimens.

“Everybody is kind of dumbfounded that this has happened,” Le Duc said Wednesday.