The District government shut down its own public health laboratory yesterday because years of neglect had left the facility at risk of causing "a public health disaster," officials said.

D.C. Health Director Ivan C.A. Walks closed the lab because it was crippled by outdated and possibly contaminated equipment, supply interruptions, an absence of quality control policies and an obsolete physical layout.

"Let's stop what we're doing . . . before we have a public health disaster," Walks said.

Walks emphasized that he has not heard anything to suggest that the lab has unacceptable levels of false test results. He credited the lab's 15 employees with performing their jobs well in spite of overwhelming problems.

"People who are dedicated work harder when they are under substandard conditions, but we decided we will not accept any level of risk," he said.

The only lab employee who isn't remaining on board for the reengineering and reopening of the lab is James B. Thomas Jr., who decided in the last few days to retire after many years as the lab's director.

Thomas could not be reached for comment last night.

The laboratory is charged with performing a wide range of testing and surveillance for the Health Department and numerous city agencies, including screening for HIV, sexually transmitted diseases and other communicable diseases for city-sponsored health clinics.

Without a lab, the District cannot carry out infectious disease programs or monitor air, food and water on its own.

"States that contract out their lab work know very well it is not the most effective approach," said Bailus Walker, chairman of the city's health policy council and a longtime proponent of improving the laboratory. "It has to be in close proximity to where the services are provided. Shipping samples to some lab in Maryland and getting in line behind other clients is not an effective way."

The District received 300,000 specimens last year, officials said, but problems have been so great in recent years that the Health Department has shipped 70 percent of them to private or public labs throughout the area.

For example, blood tests to screen for lead in children are being sent to Children's Hospital in the District, and the Food and Drug Administration laboratory in Rockville steps in as needed to analyze food-borne illnesses for the District.

In recent months, the city public health lab tested only for sexually transmitted diseases, HIV and some other communicable diseases, officials said. Now those will be farmed out as well during the 90-day shutdown.

Walks said that he has heard persistently negative comments about the lab since he assumed the city's top health job in September. He said yesterday's move is part of a broader effort to "turn over all the rocks" in his department in the coming months to address other problems that need immediate attention.

The public health lab, which occupies 15,000 square feet on the sixth floor of the city's police headquarters at 300 Indiana Ave. NW, was closed earlier this year for asbestos abatement. Repairs were needed after roof damage caused the hazardous material to disintegrate into dustlike particles.

But yesterday's closure was caused by larger issues, such as low funding by the city (the lab had a $650,000 budget last year) and repeated purchasing foul-ups that allowed the lab to run out of necessary supplies.

More importantly, said Walks and his chief deputy for health assurance, Ted Gordon, the lab had no written procedural guidelines or quality control rules.

"Without any safety and quality protocols, it was impossible for us to let operations continue," Walks said.

Walker praised Walks for ordering the shutdown. Walker has been urging city officials to overhaul the operation for years because the District had lost the ability to handle so many testing functions.

For example, the city cannot check the safety of refrigerated foods in delicatessens or determine whether fish are infected with the Pfiesteria piscicida contamination that has occurred in tributaries of the Chesapeake Bay in recent years, Walker said.

"It's unbelievable," Walker said of the lab's conditions. "I'm hoping that this action will mean a renewed effort to put in place a comprehensive public health laboratory, which is needed for a city of this size."

After the 90-day hiatus, the lab will resume as much of its recent workload as possible, Walks and Gordon said.

The city also will hire a consultant to carry out a $500,000 evaluation of the city's lab needs, a prelude to building a state-of-the-art public health laboratory. The goal, Walks said, is to bring all lab work back in house, including drug testing and other screenings performed for the police, fire and corrections departments.