Testifying at a congressional hearing in Washington, CDC Director Dr. Tom Frieden said the agency had long thought of the lapses as unrelated accidents. But two particularly serious mistakes this year caused officials to re-examine lab safety in a new light.
"In hindsight, we realize we missed a crucial pattern" of a lax safety culture, Frieden told lawmakers on the House Energy and Commerce Committee, which was seeking details about a series of lapses reported over the last decade at labs run by the Atlanta-based agency.
One incident happened last month at a CDC lab that handles bioterrorism agents. The lab was supposed to completely kill anthrax samples before sending them to two other CDC labs that had fewer safeguards for containing dangerous germs. But the higher-security lab did not completely sterilize the bacteria.
Dozens of CDC workers were potentially exposed to anthrax, but no one got sick. An internal CDC investigation released last week found serious safety lapses, including use of unapproved sterilization techniques and use of a potent type of anthrax in an experiment that did not require that germ.
In the other incident, relatively harmless bird flu virus was accidentally contaminated with a much deadlier strain. The contaminated virus was then sent to a Georgia lab run by the U.S. Department of Agriculture. The contamination was discovered in May, but the incident was not reported to CDC's top management until last week, Frieden said.
No one has been reported infected. But Frieden has said the second incident was particularly worrisome because flu — unlike anthrax — is a germ that can potentially spread easily from person to person.
CDC officials are still not sure how the contamination occurred, Frieden said.
Both Republican and Democratic lawmakers decried the lapses.
"This is not sound science. This will not be tolerated. These practices put the American public at risk," said Rep. Tim Murphy, a Pennsylvania Republican.
The committee cited several breaches at CDC labs in the last decade, including broken doors between containment rooms and hallways, inadequate air pressure to keep airborne bugs in the safest rooms and poor provisions for backup electrical power.
But lawmakers seemed most alarmed about repeated incidents in which CDC scientists shipped to other labs germs they thought were benign but were actually potent.
Another expert at the hearing noted that the CDC is considered the gold standard for lab sophistication and safety. If these kinds of problems exist at the CDC, they probably also happen at the more than 1,000 other high-level U.S. labs that handle dangerous biological agents, said Richard Ebright, a biochemist at Rutgers University.
The number of labs should be whittled down to 50, which would allow more focus and control over this kind of work, he said.
An official with the General Accountability Office did not go that far. But she said there's an urgent need for better oversight of the laboratories.
There's been no comprehensive evaluation of how many of the labs are necessary and whether adequate planning is in place to make sure they stay up-to-date, adequately staffed and safe, said Nancy Kingsbury, the GAO official.