The U.S. Postal Service plans yet another test of decontamination procedures for the Brentwood Road postal plant this weekend, but officials hope this latest in a series will lead to a complete fumigation beginning the following weekend.

At a meeting Tuesday of the Postal Service Board of Governors, Postmaster General John E. Potter said postal officials "expect to move forward with the decontamination of this facility on [the] weekend of November 16 to 17." If all goes well, the Northeast Washington facility will be fully operational by spring, Potter said.

The preliminary start date depends on the success of Saturday's test and on approval from the Environmental Protection Agency, which will monitor the test as well as the full fumigation, officials said. Postal and city officials plan a community meeting early next week to discuss the cleanup.

Postal officials preparing for the decontamination had been predicting in recent months that the fumigation process would begin much sooner, but they said subsequent tests were needed to ensure that the full fumigation was done right. In June, postal officials had said the cleanup would begin by the end of the summer. Thomas G. Day, the Postal Service's vice president for engineering, said shortly before the start of a June community meeting that the start date was weeks, not months, away.

Nothing has shown up in the testing to prevent the fumigation from starting sooner, postal officials said. They said the additional tests have been designed to make sure that the cleanup is effective and the building safe for returning workers. "Basically, we want to make sure that all of the systems are effective," said postal spokeswoman Deborah Yackley. "From the beginning, we always said that we don't want to do this fast. We want to do it right."

Yackley said the many agencies involved in the decontamination -- including the Postal Service, the EPA and the D.C. Department of Health -- decided that further testing was necessary. "The group decided to test a few systems a little more extensively," she said, "and everybody agreed that was a good idea."

Officials with the American Postal Workers Union said yesterday that their main priority is the safety of workers, not getting the cleanup done quickly. "Our primary concern is that when the building is open, it's completely safe," said union spokeswoman Sally Davidow, "and if that means that it's going to be a long and slow process, we will live with that."

Washington's principal mail-processing plant on Brentwood Road NE has been shut since Oct. 21, 2001, after two letters containing anthrax spores passed through the facility on their way to Capitol Hill. Two Brentwood postal workers -- Joseph P. Curseen, 47, and Thomas L. Morris Jr., 55 -- died of inhalational anthrax, and two others became seriously ill. Hundreds of other workers were urged to take preventive antibiotics and reassigned to five Washington area postal facilities.

The decontamination of the plant, which was recently renamed in memory of Curseen and Morris, is considered by experts to be the most ambitious reclamation of a biohazardous building in U.S. history.

In late July, tests began of the procedures and equipment that will be used. Four tests have been run to monitor the effectiveness of equipment that mixes and pumps chlorine dioxide gas, the effectiveness of the gas in killing anthrax spores and a so-called scrubber system's ability to render the gas harmless after fumigation. A three-hour test planned for Saturday will check humidity-control procedures in the building and a second scrubber system on the south side of the facility. A relative humidity of 75 percent and temperature of 75 degrees must be maintained inside for peak effectiveness of the gas.

Yackley said that so far, test results have shown "that the systems we have in place to kill the anthrax and to remove the chlorine dioxide from the building are all effective and safe."

A 17-hour test on Sept. 17 of the scrubber system was a success, said postal officials, but the EPA said it was not long enough. So a 24-hour test was done last month to ensure the effectiveness of the system.

"There has been testing and . . . retesting and additional trials that have been conducted throughout the summer in the interest of doing the fumigation right," said Patrick Boyle, a spokesman for the EPA's Mid-Atlantic Region.

The EPA must issue a "crisis exemption" for chlorine dioxide to be used during a full decontamination. Boyle said that if Saturday's test goes well, the exemption could be issued early next week, clearing the way for the fumigation to begin.

Corey Thompson, safety and health specialist for the American Postal Workers Union, has reviewed technical data from the tests and expressed confidence in the procedures. "So far, there's been a number of tests on a number of different processes," Thompson said. "From a technical perspective, those tests have gone well."

A number of Brentwood workers have said they are apprehensive about returning to work in the building after the fumigation. "Management has not convinced us that we can trust them and that they have our best interests at heart," said Terrell Worrell, 39, a forklift driver at Brentwood. Worrell said he worries that some spores might be missed.

Yesterday, several hundred Brentwood workers attended a remembrance ceremony in honor of Curseen and Morris. The service, at Greater Mount Calvary Holy Church in Northeast, was originally scheduled for Oct. 22 but was called off because of traffic gridlock that morning after a sniper shooting in Montgomery County.

Signs warn of anthrax spores at the Brentwood postal facility, which has been closed for more than a year. Officials hope to begin full fumigation there the weekend after next.