WASHINGTON, D.C. (CBS/AP) -- The federal government shutdown furloughed as many as 800,000 of the nation's 2.1 million federal workers as it hit early Tuesday after a bitterly divided Congress failed to approve a temporary spending bill to keep the government running.
The shutdown will have far-reaching consequences for some, but minimal impact on others.
Mail will be delivered. Social Security and Medicare benefits should continue to flow. But vacationers will be turned away from national parks and Smithsonian museums. Low-to-moderate income borrowers and first-time homebuyers seeking government-backed mortgages could face delays.
Here's a look at how services will or will not be affected by Congress' failure to reach an agreement averting a government shutdown:
Federal air traffic controllers remain on the job and airport screeners willkeep funneling passengers through security checkpoints. Federal inspectors will continue enforcing safety rules.
The State Department will continue processing foreign applications for visas and U.S. applications for passports, since fees are collected to finance those services. Embassies and consulates overseas will continue to provide services to American citizens.
Social Security and Medicare benefits should keep coming, but there could be delays in processing new disability applications. Unemployment benefits will still go out.
Federal courts will continue operating normally for about 10 business days after the start of the shutdown, roughly until the middle of October. If the shutdown continues, the judiciary will have to begin furloughs of employees whose work is not considered essential. But cases will continue to be heard.
Deliveries will continue as usual because the U.S. Postal Service receives no tax dollars for day-to-day operations. It relies on income from stamps and other postal fees to keep running.
All national parks will be closed, as would the Smithsonian museums, including the National Zoo in Washington. Visitors using overnight campgrounds or other park facilities would be given 48 hours to make alternate arrangements and leave the park. Among the visitor centers that would be closed: the Statue of Liberty and Ellis Island in New York, Independence Hall in Philadelphia, Alcatraz Island in San Francisco Bay and the Washington Monument.
New patients will not be accepted into clinical research at the National Institutes of Health, but current patients will continue to receive care. Medical research at the NIH will be disrupted and some studies will be delayed. The Centers for Disease Control and Prevention will be severely limited in spotting or investigating disease outbreaks, from flu to that mysterious MERS virus from the Middle East.
The Food and Drug Administration will handle high-risk recalls suspend most routine safety inspections. Federal meat inspections will be expected to proceed as usual.
A small number of Head Start programs, about 20 out of 1,600 nationally, could feel the impact right away. The federal Administration for Children and Families says grants expiring about Oct. 1 will not be renewed. Over time more programs would be affected. Several of the Head Start programs that could immediately feel the pinch are in Florida. It's unclear if they will continue serving children.
The Special Supplemental Nutrition Program for Women, Infants and Children, known as WIC, could shut down. The program provides supplemental food, health care referrals and nutrition education for pregnant women, mothers and their children. School lunches and breakfasts will continue to be served, and food stamps, known as the Supplemental Nutrition Assistance Program, or SNAP, will continue to be distributed. But several smaller feeding programs will not have the money to operate.
Americans will still have to pay their taxes and file federal tax returns, but the Internal Revenue Service says it will suspend all audits. Got questions? Sorry, the IRS says taxpayer services, including toll-free help lines, will be shutdown as well.
Many low-to-moderate incomes borrowers and first-time homebuyers seeking government-backed mortgages could face delays during the shutdown. The Federal Housing Administration, which guarantees about 30 percent of home mortgages, won't underwrite or approve any new loans during the shutdown. Action on government-backed loans to small businesses will be suspended.
NASA will continue to keep workers at Mission Control in Houston, Texas and elsewhere to support the International Space station, where two Americans and four others are deployed. The National Weather Service will keep forecasting weather and issuing warnings and the National Hurricane Center will continue to track storms. The scientific work of the U.S. Geological Survey will be halted.
The majority of the Department of Homeland Security's employees are expected to stay on the job, including uniformed agents and officers at the country's borders and ports of entry, members of the Coast Guard, Transportation Security Administration officers, Secret Service personnel and other law enforcement agents and officers. U.S. Citizenship and Immigration Services employees would continue to process green card applications.
The military's 1.4 million active duty personnel will stay on duty, but their paychecks could be delayed. About half of the Defense Department's civilian employees will be furloughed.
All 116 federal prisons will remain open, and criminal litigation will proceed.
Most services offered through the Department of Veterans Affairs will continue because lawmakers approve money one year in advance for the VA's health programs. Veterans will still be able to visit hospitals for inpatient care, get mental health counseling at vet centers or get prescriptions filled at VA health clinics. Operators will still staff the crisis hotline and claims workers will still process payments to cover disability and pension benefits. But those veterans appealing the denial of disability benefits to the Board of Veterans Appeals will have to wait longer for a decision because the board will not issue any decisions during the shutdown.
Federal occupational safety and health inspectors will stop workplace inspections except in cases of imminent danger.
The federal Office of Personnel Management also has developed a furlough guide to help answer questions about how a government shutdown would affect you.
Here's a look at what stays open and what closes under the shutdown.
WHAT STAYS OPEN:
* U.S. Postal Service.
* Social Security.
* Active-duty military will keep working, but will not get paid until the funds are available.
* Air-traffic control.
* Border security.
* Emergency and disaster assistance.
* Federal law enforcement.
* IRS can still process electronic returns and payments only.
* Any federal agency that's subject to appropriations. Each agency has the discretion to decide who is "excepted" or "emergency", and who is furloughed.
* All National Parks.
* All federally-funded museums, including Smithsonian and the National Zoo.
* All federal government websites.
* Research by Health and Human Services stops. So does the grant process. Depending on how long it lasts, that will also impact medical research at hospitals and universities.
* Applying for Social Security. If you're a new retiree, your application won't be processed.
* IRS walk-in centers. Your paper tax return will not be processed.
* Loan applications for small businesses, college tuition, or mortgages.
* All Library of Congress buildings. All public events will be cancelled and web sites will be inaccessible.
* Federal contractors will be out of work.
* Federal workers (except "excepted" or "emergency" personnel) will not be allowed to work, not even from home. No blackberry, no smartphone, no laptop. Not even allowed to check work email.
(Copyright 2013 by CBS San Francisco. All Rights Reserved. This material may not be published, broadcast, rewritten, or redistributed.)
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