WASHINGTON — Intruders could easily break into two U.S. laboratories where researchers handle some of the world’s deadliest germs, according to congressional investigators. The Associated Press identified the vulnerable lab locations as Atlanta and San Antonio.

The serious security problems at the two labs were described by the Government Accountability Office in a report expected to be released publicly as early as today. The GAO, Congress’ investigative and auditing arm, did not identify the labs except to say they were classified as Biosafety Level 4 facilities, but the report included enough details for the AP — and others knowledgeable about such labs — to determine their locations.

Biosafety Level 4 labs conduct research on deadly germs and toxins.

In Texas, the Southwest Foundation for Biomedical Research features an outside window that looks directly into the room where the deadly germs are handled. The lab, which is privately run, also lacks many security cameras, intrusion detection alarms or visible armed guards at its public entrances. Officials there said they will tighten security.

“We already have an initiative under way to look at perimeter security,” said Kenneth Trevett, president of the lab in San Antonio. “We’re waiting for additional input but we’re not waiting long. The GAO would like us to do some fairly significant things. They would like us to do it sooner rather than later.”

The other lab described with weak security in the report is operated by Georgia State University in Atlanta. That lab lacked complete security barriers and any integrated security system, including any live monitoring by security cameras. During their review, investigators said they watched an unidentified pedestrian enter the building through an unguarded loading dock.

“Georgia State clearly wants its BSL-4 to be as safe as possible,” said DeAnna Hines, assistant vice president for university relations. “We are already taking steps that will enhance the lab’s safety and security standards.” Hines did not confirm the school’s research lab was the one mentioned in the congressional report as lacking proper security.

Investigators said the lab in San Antonio used unarmed guards inside antiquated guardhouses with a gate across the access road. An outside company monitors alarms at the lab and calls police in emergencies, which investigators said could delay a quick response in a crisis. They called the San Antonio lab the most vulnerable of all the labs they studied.

The federal Centers for Disease Control and Prevention approved the labs in San Antonio and Atlanta to handle the deadly organisms despite the security weaknesses. The three other BSL-4 labs in the U.S. feature impressive security, the report said. Those include the CDC’s own facility, also in Atlanta; the Army’s lab at Fort Detrick, Md.; and the University of Texas Medical Branch in Galveston.

Fort Detrick is on a secure military base, but it is known for a recent internal problem. Bruce Ivins, a scientist at the Army’s biodefense lab at Fort Detrick, killed himself in July as prosecutors prepared to indict him for murder in the anthrax letter attacks, which killed five people.

The CDC lab is on the agency’s high-security campus.

The viruses researched in the highest security labs include ebola, marburg, junin and lassa. All can cause incurable illnesses.

The chairman of the House Energy and Commerce Committee, Rep. John Dingell, D-Mich., urged the CDC to quickly identify all security weaknesses at the high-containment research labs and fix any problems. Dingell has been investigating security problems associated with such labs around the country. He said at least six additional high-containment labs are under construction.

The Associated Press reported in October 2007 that U.S. laboratories working with deadly organisms have experienced more than 100 accidents and missing shipments since 2003 — and the number is increasing as more labs do the work.

A CDC spokesman, Von Roebuck, said each of the five labs described in the new report has its own security plan designed to fit the lab’s particular security assessments.