WASHINGTON (Reuters) -Hundreds of thousands of U.S. federal workers have been ordered not to report to work, while others have been told to stay on the job during the U.S. government shutdown, which started on October 1.

Here is an overview of who has been furloughed at major government agencies, based on their shutdown plans.

DEFENSE DEPARTMENT

The 2 million active-duty members of the military remain on duty.

Roughly 55% of the Defense Department's 740,000 civilian employees have been furloughed, including those involved in training, procurement and administrative support. Civilians working on cybersecurity, medical care, weapons systems maintenance, intelligence and logistics are still working.

DEPARTMENT OF HOMELAND SECURITY

Only 5% of the Department of Homeland Security's 271,000 workers have been furloughed, including those involved in research, planning, training, and auditing.

Secret Service agents, immigration and border officers, airport security screeners, Coast Guard personnel, and Federal Emergency Management Agency emergency workers remain on the job.

DEPARTMENT OF JUSTICE

About 10% of the Justice Department's 115,000 employees are furloughed, mainly in administrative and policy roles.

Prison guards, FBI agents, criminal prosecutors and other front-line law enforcement are required to work.

DEPARTMENT OF STATE

The State Department has furloughed 62% of its 27,000 employees, including those awarding new grants and contracts.

All U.S. embassies remain open, and those working on visas and passports will continue to do their jobs. 

TREASURY DEPARTMENT

All 74,000 employees of the tax-collecting Internal Revenue Service remain on the job through Tuesday, October 7. It is not clear how many would be furloughed after that.

Outside of the IRS, Treasury would continue to distribute Social Security checks and tax refunds and service the nation's $37.5 trillion debt, while it would cease other duties, such as audits and government-wide accounting. Treasury does not specify how many non-IRS employees would be furloughed. 

DEPARTMENT OF HEALTH AND HUMAN SERVICES

Roughly 41% of HHS's 78,000 employees are furloughed. 

The Centers for Disease Control and Prevention, where 2 out of 3 workers have been furloughed, is continuing its core outbreak response, but is not providing guidance to states and has paused much of its research and surveillance work.

The Centers for Medicare & Medicaid Services has furloughed half of its employees and has paused much of its oversight work.

The Food and Drug Administration, where 14% of employees are furloughed, continues safety-critical work like product recalls and import screening, but has paused research and is not accepting most new drug and medical device submissions.

The National Institutes of Health, which has furloughed 3 out of 4 of its workers, has paused its research activity and is not issuing new grants, but continues patient care. 

DEPARTMENT OF COMMERCE

The Commerce Department has furloughed 81% of its 43,000 employees.

Employees of the National Oceanographic and Atmospheric Administration will continue weather forecasting, fisheries enforcement and other safety-critical activities, but 9 out of 10 NOAA employees will be furloughed, including those involved in research, grants and contracts and animal/laboratory maintenance.

Most employees at the Census Bureau and the Bureau of Economic Analysis have been furloughed, which halts surveys, statistical releases and economic data publication.

The 14,000 employees of the U.S. Patent and Trademark Office will remain on the job until funding from reserves and fees runs out.

SOCIAL SECURITY ADMINISTRATION

Most Social Security workers are still on the job, with only 12% of the agency's 52,000 employees furloughed. That could change if the shutdown drags on, the agency says.

Some workers at field offices and those handling benefit applications and appeals have been furloughed, while those who handle benefit payments are still working.

DEPARTMENT OF TRANSPORTATION

Roughly 23% of the Transportation Department's 54,000 workers are furloughed, including those involved in research, policy and regulations.

Air traffic controllers, safety inspectors and those overseeing highway and transit funds continue to work.

NATIONAL AERONAUTICS AND SPACE ADMINISTRATION

NASA has furloughed 83% of its 18,000 employees, including those involved in research, public affairs, grants and contracts. 

Those involved with the International Space Station and satellites remain on the job.

DEPARTMENT OF AGRICULTURE

Some 49% of USDA's 86,000 employees have been furloughed, including those handling grants and loans and those producing statistical reports.

Food safety inspectors, Forest Service firefighters, workers responding to disease or pest outbreaks, and workers overseeing nutrition programs are still working.

ENVIRONMENTAL PROTECTION AGENCY

The EPA has been hit hard by the shutdown, with 89% of the agency's 15,000 workers on furlough, including those involved in permitting, research and civil enforcement.

Security guards, criminal investigators, and those involved in emergency response are still working.

DEPARTMENT OF EDUCATION

Roughly 87% of the Department of Education's 2,450 employees have been furloughed, including those involved in regulations, new grants, and civil rights investigations.

Workers who distribute student aid and grants to low-income schools are still working.

FEDERAL TRADE COMMISSION

All but 5% of the FTC's workers have been furloughed, including those working on consumer protection investigations and antitrust review. Attorneys and investigators involved in ongoing litigation will keep working.

SECURITIES AND EXCHANGE COMMISSION

Likewise, 91% of the SEC's 4,300 employees have been furloughed, including those reviewing corporate filings, oversight of investment advisers, and routine enforcement.

Market monitoring teams and those handling urgent fraud matters will continue to work.

SMALL BUSINESS ADMINISTRATION

Roughly 24% of SBA's 6,200 employees have been furloughed, including those who approve new loans and work on entrepreneurial development. 

Workers who handle existing loans and disaster loans continue to work.

FEDERAL COMMUNICATIONS COMMISSION

Some 81% of the FCC's 1,300 workers would be furloughed, including those handling consumer protection and complaints, licensing services, equipment authorization and spectrum management. Those involved in spectrum auctions and critical security and technology would remain on the job. 

DEPARTMENT OF VETERANS AFFAIRS

The VA is largely insulated from a shutdown as most of its budget does not come from annual appropriations. Only 3.2% of the agency's 462,000 workers have been furloughed, including those involved in research, communications, and oversight. Medical workers and benefits administrators remain on the job. 

DEPARTMENT OF HOUSING AND URBAN DEVELOPMENT

Roughly 67% of HUD's 6,100 employees are furloughed, including those issuing new grants and those involved in fair-housing investigations.

Those handling Federal Housing Administration insurance and ongoing rental-assistance payments continue to work.

DEPARTMENT OF LABOR

Roughly 75% of the Labor Department's 13,000 workers are furloughed, including those involved in economic data reports and civil rights enforcement.

Those involved in workplace safety, workers' compensation payments and unemployment insurance continue to work.

DEPARTMENT OF ENERGY

Some 63% of the Energy Department's 15,500 employees are furloughed, including those involved in grant and research work. 

Those working on nuclear security, cybersecurity, and power safety continue to work.

DEPARTMENT OF THE INTERIOR

The Interior Department has furloughed 50% of its 58,000 employees, including maintenance and customer service workers at the National Park Service, fish biologists, and those handling new energy or land use permits.

Teachers and other workers at the 55 schools run by the Bureau of Indian Education are still on the job. Law enforcement officers at national parks, wildlife refuge rangers, firefighters, and dam and power operators continue working