(Reuters) -U.S. government services would be disrupted and hundreds of thousands of federal workers furloughed without pay if Congress fails to provide funding for the fiscal year starting Oct. 1. Workers deemed "essential" would remain on the job, but without pay.
Many government agencies have not updated shutdown plans they have prepared in the past. Here is a guide to what would stay open and what would shut down:
MILITARY
The 2 million U.S. military personnel would remain at their posts, but roughly half of the Pentagon's 800,000 civilian employees would be furloughed.
Contracts awarded before the shutdown would continue, and the Pentagon could place new orders for supplies or services needed to protect national security. Other new contracts, including renewals or extensions, would not be awarded. Payments to defense contractors such as Boeing (NYSE:BA), Lockheed Martin (NYSE:LMT) and RTX, formerly known as Raytheon (NYSE:RTN), could be delayed.
The Department of Energy's National Nuclear Security Administration would continue maintaining nuclear weapons.
LAW ENFORCEMENT
According to the Justice Department's 2021 contingency plan, agents at the FBI, the Drug Enforcement Administration (DEA) and other federal law enforcement agencies would remain on the job, and prison staffers would continue to work.
Criminal prosecutions, including the two federal cases against former President Donald Trump, would continue. Most civil litigation would be postponed.
Aid to local police departments and other grants could be delayed.
Border Patrol and immigration enforcement agents would continue to work, as would customs officers, according to the Department of Homeland Security's 2022 plan. The Secret Service and the Coast Guard would also continue operations.
Most of the Federal Trade Commission's consumer-protection workers would be furloughed, as would half of its antitrust employees.
FEDERAL COURTS
Federal courts have enough money to stay open until at least Oct. 13. Activities might be scaled back after that point. The Supreme Court would stay open as well.
TRANSPORTATION
Airport security screeners and air-traffic control workers would be required to work, according to recent contingency plans, though absenteeism could be a problem. Some airports had to suspend operations during a shutdown in 2019 when traffic controllers called in sick.
Training for new air traffic controllers would stop, which Transportation Secretary Pete Buttigieg has warned could worsen a shortage of qualified workers.
Some major infrastructure projects could face delays as environmental reviews and permitting would be disrupted, according to the White House.
FOREIGN AFFAIRS
U.S. embassies and consulates would remain open under the State Department's 2022 shutdown plan. Passport and visa processing would continue as long as there were sufficient fees to cover operations. Nonessential official travel, speeches and other events would be curtailed.
Some foreign aid programs could run out of money as well.
NATIONAL PARKS AND NATURAL RESOURCES
It's not clear how national parks, national monuments and other sites would be affected. Many remained open during a 2018-2019 shutdown, through restrooms and information desks were closed and waste disposal was halted. They were closed during a 2013 shutdown.
Wildfire fighting efforts would continue, according to the Agriculture Department's 2020 contingency plan, though timber sales on national forest lands would be curtailed and fewer recreation permits would be issued.
SCIENCE
Scientific research would be disrupted as agencies like the National Institutes of Health, the National Science Foundation and the National Oceanographic and Atmospheric Administration (NOAA) would furlough most of their workers, according to recent contingency plans.
The National Aeronautics and Space Administration (NASA) would continue to support the International Space Station and track satellites, but 17,000 of its 18,300 employees would be furloughed.
Weather forecasts and fisheries regulation would continue, as would patent and trademark reviews. Tests of new drugs and medical devices would continue.
HEALTH
The Centers for Disease Control and Prevention (CDC) would continue to monitor disease outbreaks, though other public health activities could suffer as more than half of the agency's workers would be furloughed.
The National Institutes of Health would furlough most of its staff and delay new clinical trials for medical treatments.
Healthcare services for veterans and Native Americans would continue.
Most inspections of hazardous waste sites and drinking water and chemical facilities would stop.
Food-safety inspections by the Food and Drug Administration (FDA) could be delayed.
FINANCIAL REGULATION
The Securities and Exchange Commission (SEC) would furlough roughly 90% of its 4,600 employees and suspend most activities, leaving only a skeleton staff to respond to emergencies.
Likewise, the Commodities and Futures Trading Commission (CFTC) would furlough almost all of its employees and cease oversight, enforcement and regulation, according to its 2021 plan.
The Federal Reserve, the Federal Deposit Insurance Corporation (FDIC) and the Office of the Comptroller of the Currency would continue as normal, as they are funded by industry fees rather than congressional appropriations.
ECONOMIC DATA
Important economic data reports from the Labor Department's Bureau of Labor Statistics would be suspended, including the monthly unemployment report, due out on Oct. 6, and price reports due the following week. Reports from the Commerce Department's Bureau of Economic Analysis and the Census Bureau could be suspended as well, including retail sales and housing starts.
SOCIAL SECURITY, MEDICARE AND OTHER BENEFITS
The Social Security Administration would continue to issue retirement and disability benefits, and payments would continue under the Medicare and Medicaid health programs.
Military veterans' benefits would also continue, according to a 2021 contingency plan.
Food assistance administered through the Supplemental Nutrition Assistance Program could be affected, as grocery stores would not be able to renew their licenses.
TAX COLLECTION
The Internal Revenue Service (IRS) would operate as normal, and all 83,000 employees would continue to be paid because the agency's funding would not expire.
DISASTER RESPONSE
The Federal Emergency Management Agency (FEMA) would risk running out of funds for disaster relief and long-term recovery projects.
EDUCATION
Pell Grants and student loans would continue to be paid, but could be disrupted as most Education Department employees would be furloughed, according to the agency's 2021 plan.
A protracted shutdown could "severely curtail" aid to schools, universities and other educational institutions, the department says. It also could delay funds that are due to be awarded later in the year.
CHILD CARE
According to the White House, 10,000 children from low-income families would lose access to the Head Start preschool program.
SMALL BUSINESS SUPPORT
The Small Business Administration would not be able to issue any new loans, though loans for businesses hurt by natural disasters would continue.
LABOR
Workplace safety inspections would be limited and investigations into unfair pay practices would be suspended, according to the White House.
The ability of the National Labor Relations Board (NLRB) to mediate labor disputes would be curtailed because almost all of its 1,200 employees would be furloughed, according to a 2022 plan.
WHITE HOUSE
In the 2018-2019 shutdown, the White House furloughed 1,100 of 1,800 staff in the Executive Office of the President. Some offices, such as the National Security Council, continued at full strength, while others like the Office of Management and Budget (OMB) were scaled back sharply.
White House furloughs could make it harder to comply with the impeachment investigation of President Joe Biden, a Democrat, by Republicans in the House of Representatives.
MAIL DELIVERY
The U.S. Postal Service (USPS) would be unaffected as it does not depend on Congress for funding.