Shortly after 7 a.m. yesterday, Customs Commissioner Robert C. Bonner sent his agency's 22,000 employees a message that tried to embrace the past and look to the future. Customs, a proud agency for 213 years, will develop even richer traditions as part of the Department of Homeland Security, Bonner said.

At the Federal Emergency Management Agency, Director Joe M. Allbaugh wrote his 5,100 employees that the transition to Homeland Security "will undoubtedly present new challenges" but also "outstanding new opportunities." Allbaugh concluded his memo by reminding FEMA employees that "our country depends on your continued enthusiasm, commitment and good work."

Across the government yesterday, Bush administration officials, in various ways, tried to reassure those who are scheduled to move into the new department. More than 170,000 workers are being swept up in the reorganization, the largest since the creation of the Defense Department.

"We're trying to set the tone, that we don't have all the answers but we are moving forward with an important mission," one agency official said.

The Senate approved legislation creating the department late Tuesday after a lengthy fight that ended mostly on President Bush's terms. In addition to Customs and FEMA, the Immigration and Naturalization Service, the Coast Guard, the Transportation Security Administration and the Animal and Plant Inspection Service are among the large agencies merging into the department.

The Bush administration will have broad power to determine how Homeland Security employees are hired, fired and paid. In particular, administration officials will be able to reassign workers more quickly than is possible under standard work rules.

The fight on Capitol Hill over those and other issues appears to have exacerbated the uncertainty that normally accompanies a reorganization.

According to the agency official, employees are asking: What is going to happen to me? Who is my boss going to be? Is my quality of life going to change, for better or for worse? "The longer that lingers, the longer the anxiety lingers. We've got to answer those questions as quickly as possible," the official said.

Some answers may take time. Agencies will move into the department over the course of a year, administration officials said. It could take six months "to address the personnel changes of the department," Sen. George V. Voinovich (R-Ohio) said yesterday. It may take years to realign computer systems, budgets and business procedures.

Administration officials agree that they do not want a cumbersome, disruptive reorganization that distracts employees who should be focused on terrorism and other threats to the nation.

Yesterday, Tom Ridge, the president's homeland security adviser, acknowledged that the reorganization will take time but expressed confidence in the many employees who will make up the government's third-largest department.

"We're going to make sure that they continue to do the great work they've done in the past," Ridge said on ABC's "Good Morning America."

Kay Coles James, director of the Office of Personnel Management, said unions and professional groups will have "significant input shaping the personnel systems for the department."

The legislation creating the department "preserves basic civil service principles and the sanctity of the merit system and veterans' preference, and protects federal employees from prohibited personnel actions," she said.

At the same time, she added, Congress also has given the administration "the agility needed to get the right people to the right place at the right time."

Labor leaders, who failed to limit Bush's power to abolish union contracts by invoking national security, questioned whether the reorganization can succeed if unions are not at the table when the department is established.

"The two most important things needed to improve homeland security are frontline employees with a real voice in how the work gets done and the funding and resources to bolster personnel, equipment and technology. The homeland security bill contains neither," said Colleen M. Kelley, president of the National Treasury Employees Union.

Internet Talk Show Leon Schachter, director of the Defense Department's office of hearings and appeals, will discuss security clearances on "FEDtalk" at 11 a.m. tomorrow on federalnewsradio.com.

Stephen Barr's e-mail address is barrs@washpost.com.