The Internal Revenue Service headquarters in Washington, D.C. (Andrew Harrer/Bloomberg)

Three of the largest federal agencies will close to the public on Friday, the first time since the government shutdowns of the 1990s that large corners of the government have ceased operations on a weekday.

The mass furlough of 115,000 employees at the Internal Revenue Service, Environmental Protection Agency, Department of Housing and Urban Development and the small Office of Management and Budget — 5 percent of the federal workforce — is happening because of the budget cuts known as sequestration.

Even in a government shutdown, thousands of essential employees are still called to work. In this case, the only ones in the office will be a small number of Senate-confirmed presidential appointees who are exempt from furloughs and emergency responders.

The closures, the first of several around summer holiday weekends and other days this fiscal year, were conceived as a way for furloughs to do the least damage to employees and the public. The Friday before Memorial Day is a vacation day for many, and the volume of calls for tax help, housing assistance or to report an environmental problem is relatively low, officials said.

“From a public service perspective, it means there will be no service,” said Colleen Kelley, president of the National Treasury Employees Union, which represents some EPA workers as well as employees at the embattled IRS. (The agency is the focus of congressional hearings for its targeting of conservative groups seeking tax exempt status.)

Service at the agencies will be limited Friday.

Some Web-based tools and phone-based automated services will continue to function for taxpayers. At the housing agency, hotlines at the Federal Housing Administration and at a program for low-income families called HOPE will be open because they are run by contractors. HUD officials cautioned, though, that those staffs will have limited authority to answer questions and resolve problems.

But homeowners looking for housing counseling and developers and local governments with technical issues or questions about pending projects will have to wait until next week, officials said.

The EPA will still respond to environmental emergencies but will be “unable to perform core functions” like site inspections and some criminal investigations, spokeswoman Alisha Johnson said in a statement.

And close to 400 taxpayer assistance centers across the country will be closed, as will the IRS’s toll-free hotlines and Taxpayer Advocate Service. No tax returns will be processed, and there will be no enforcement. But tax-payment deadlines will not be pushed back.

But the reality is that much of the work that gets done every day at the EPA, HUD and the Washington-based budget office does not serve the public directly. Most agencies are requiring staggered furloughs under sequestration, and they are cutting into missions and paychecks.

But some say closing down may not be such a disaster for the public.

“Unless something dramatic occurs such as the Great Lakes catching fire, I don’t think the public will think much about it . . . unfortunately,” said John O’Grady, president of the American Federation of Government Employees Local 704, which represents EPA employees.

The EPA makes many grants to state, local governments and nonprofit groups to enforce federal environmental laws. HUD does the same thing, overseeing local housing authorities and voucher programs, for example.

Both have large enforcement roles. But the mission is long-term rather than immediate.

“We could have done better customer service and provided employees with more flexibility to choose all of their days off,” said Carolyn Federoff, an attorney and AFGE official at HUD’s Boston office. “But in the overall scheme of things, the impact will be small.”

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