The U.S. Army research facility in Utah, which shipped live anthrax samples to several labs in the country and abroad, including South Korea, Australia and Canada, lacked effective procedures for killing the bacteria, USA Today reported Wednesday, citing an investigation by the Centers for Disease Control and Prevention (CDC).

The research base at the center of the scandal -- Dugway Proving Ground -- was initially reported to have shipped live anthrax to at least 51 labs in 17 states and three countries. However, the CDC report accessed by USA Today allegedly shows that the deadly bacteria was shipped out at least 74 times to dozens of labs in the U.S. and at least five foreign countries between January 2005 and May 2015.

Moreover, the procedure for deactivating anthrax using radiation “did not account for the variable amounts of spores treated in the gamma cell irradiator,” CDC reportedly noted in its latest investigation. The procedure was also not standardized using “control spore samples at varying concentrations, volumes, and levels of irradiation.”

According to an earlier report by USA Today, the research facility also faced potential sanctions in 2007 for failing to properly kill anthrax specimens and ignoring test results that indicated its killing process, which used a chemical method, was not effective.

Anthrax, caused by the bacterium Bacillus anthracis, can cause a deadly illness if it becomes airborne. In 2001, letters containing anthrax spores, which are capable of surviving in harsh conditions for decades, were sent through the U.S. mail to government and media targets, killing five people and infecting at least 17 others.