Congress is questioning the ability of the Center for Disease Control to oversee dangerous research after internal reports revealed two incidents of researchers being exposed to anthrax and bird flu.

Following a report of 80 researches being exposed to live anthrax in a government lab in Atlanta last month, a new internal report Friday revealed the CDC transported samples of a dangerous strain of the bird flu to the U.S. Department of Agriculture in March, according to Reuters.

CDC Director Dr. Thomas Frieden said he was upset the bird flu incident had not been reported to senior officials.

"We need to look at our culture of safety throughout all of our laboratories," Frieden said. "I'm upset, I'm angry. I've lost sleep over it, and I'm doing everything I can to make sure it doesn't happen again."

Since the incidents have come to light, the CDC has suspended any transfers of biological materials from and to high-biosecurity labs.

Both the CDC bioterror lab that handled the anthrax bacteria and the agency's influenza lab are closed pending further study of what happened.

But the lab in Atlanta in which researchers may have been exposed to anthrax had a similar breach in 2006, which caused some experts to raise eyebrows.

"That the same kind of incident can recur shows that the CDC does not learn from its own mistakes," molecular biologist Richard Ebright of Rutgers University and an expert on biosafety said in a telephone interview to Reuters.

In the investigation into the most recent incident, officials found that there is a lack of guidance for decontamination procedures.

As a result, a new position has been created -- lead laboratory science -- to improve the CDC's accountability for safety and includes a directive to set up an external advisory committee on biosafety.