federal workers

More than 2 million federal workers will see their paychecks delayed — and 800,000 of them might never get repaid. This is, by a fair margin, the biggest immediate consequence of the shutdown. There are the 1.3 million "essential" civilian employees who will keep working. These workers will eventually get paid. It's a different story for the 800,000 or so workers deemed "nonessential." These employees had to come in for a few hours Tuesday, get their files in order, and then go home without compensation, indefinitely. And it's unclear if they'll ever receive back pay.

veterans

Millions of veterans may not receive benefits if the shutdown lasts more than two weeks. Officials at the Department of Veterans Affairs have told Congress that they probably won't have enough money to pay disability claims or make pension payments for veterans if the government shutdown lasts more than two or three weeks. That could affect about 3.6 million veterans.

the flu program

The Centers for Disease Control and Prevention will stop its flu program. Every fall, it monitors the spread of the flu and figures out how best to direct vaccine programs. During the shutdown, however, it will be "unable to support the annual seasonal influenza program," the Department of Health and Human Services said. The CDC also has to stop providing support to states "for infectious disease surveillance."

the economy

Economist Mark Zandi argues that the furloughs could shave 0.3 percentage points off fourth-quarter GDP growth (although some of that activity would come back if the workers get back pay). This doesn't include federal contractors, who will start furloughing employees as contracts dry up.

Nutritional programs

The Agriculture Department will stop supporting the Special Supplemental Nutrition Program for Women, Infants and Children (WIC), which helps pregnant women and new moms buy healthful food and provides nutritional information and health care referrals It aids about 9 million Americans. The USDA estimates that most states have funds and authority to continue their programs for "a week or so," but they'll "likely be unable to sustain operations for a longer period."

food-safety operations

The Food and Drug Administration will have to cease most of its food-safety operations. However, thousands of inspectors will continue to check meat and poultry facilities.

small business financing

The Small Business Administration has provided guarantees for $106 billion in loans to more than 193,000 small businesses over the past four years. It also runs programs to help small firms win government contracts, help veteran-owned businesses and boost trade. All that will cease in the shutdown. The exception is the Disaster Loan Program, which steps in during emergencies.

Head Start programs

There are about 1,600 Head Start programs providing education, health, nutrition and other services to roughly 1 million low-income children and their families. Initially, only about 20 programs will be affected — the programs whose federal grants expire on Oct. 1 and don't get renewed. Over time, more programs will likely be affected.

Disability benefits

The Social Security Administration won't have enough staff to schedule new hearings for those applying for disability benefits. And the Veterans Appeal Board will be closed, which means veterans appealing a decision on disability benefits will have to wait until the shutdown ends.

NIH

As long as the government is shut down, the National Institutes of Health said it will turn away about 200 patients each week from its clinical research center, including children with cancer.

Washington post