Rep. Tom Davis, R-Va., the ranking member of the House Committee on Oversight and Government Reform, called for the probe Tuesday in a letter to committee chairman Rep. Henry Waxman, D-Calif.

"The integrity of BioSafety Level 3 and 4 laboratory procedures," Davis wrote, referring to the highest security level facilities, "is emerging as a critical national and homeland security issue" in the wake of a series of revelations about equipment failures and the accidental release of dangerous germs and other pathogens.

There was no immediate response from Waxman's office.

Davis referred in his letter to two incidents at Texas A&M University's bioweapons lab in early 2006, in which staff were exposed to deadly bacteria, but which were not reported, as required, to the U.S. Centers for Disease Control.

Last month, CDC ordered the university to cease work on certain pathogens until an investigation into the matter was completed.

Davis' letter also referenced an incident at the CDC itself, where a power outage last month shut down a vital ventilation system in the centers' bio-terror laboratory.

Davis said the incidents raised questions about security and other regulations at level 3 and 4 facilities, which he said had proliferated since Sept. 11, 2001.

He also pointed out that the Government Accountability Office was looking into the issue and could provide testimony or other assistance to the committee.