WASHINGTON — For millions of Americans awaiting coronavirus cash, help is not on the way.

Although the $2 trillion stimulus bill passed last month includes payments of up to $1,200 for everyone who makes less than the limit, many Americans will fall through the cracks. That includes most college kids, immigrants without Social Security numbers and some disabled adults.

Why so many gaps? Part of it is the urgency that faced Congress as it rushed to get money to Americans as fast as possible. There wasn't much time to fine-tune the bill to address every contingency. Lawmakers opted to base eligibility on tax returns, even though many people don't file them.

Congress also wanted to ensure that the money goes to those who really need it now. Most Americans could use some extra cash even in the best of times. But some people's livelihoods have been more directly affected by the pandemic than others.

For those who qualify, payments will start going out from the IRS in mid-April. The IRS is using 2019 tax returns to determine eligibility or 2018 returns for those who haven't filed for 2019 yet.

Here's a look at who falls through the cracks:

College students and 17-year-olds

If someone else claims you as a dependent on their taxes, you won't get your own check. Parents will get an extra $500 payment per child, but that's only for kids under 17.

Most 17-year-olds, some young adults and many of the country's roughly 20 million college students are claimed by their parents as dependents. They won't get checks, and their parents won't get an extra $500.

"They're not on their own. And so you feed them and you still provide for them," said Susan Anderson of Lubbock, Texas, who has a 19-year-old at home and a 23-year-old about to graduate from college. "So you're not getting anything, and they're not getting anything. There's a huge gap."

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Disabled people whose parents support them

People who get disability benefits from the Social Security Administration or Veterans Affairs are eligible for the payments — but not disabled adults who are claimed as dependents by their parents or other relatives on their taxes.

Jennifer Irwin's son Simon, 21, who is nonverbal, lives about an hour's drive from her Delaware home at a center for disabled adults, where he was placed by the state. Because she claims him on her taxes, he won't get a check — a blow Irwin described as "another nail in the coffin."

"Just because he's not under 17 doesn't mean he should be excluded from the credit parents are getting. He's still entirely dependent. I still buy all his clothes," Irwin said. "It's discouraging. I mean, we struggle enough as it is."

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Seniors living with their kids

Senior citizens who are on Social Security or make less than the income cap are eligible. But the "dependent" rule applies to them, too. Some seniors who live with their adult children or other relatives are claimed by them as dependents on their taxes. Those seniors won't get checks.

Immigrants without Social Security numbers

You don't have to be a U.S. citizen to get a payment. But you do need a valid Social Security number.

That means immigrants with green cards and those on H-1B and H-2A visas will get payments. Nonresident aliens, temporary workers and immigrants in the U.S. illegally won't.

Babies born in 2020

The $500 payment per child, like the individual payments, is based on 2019 taxes. So parents who welcomed babies into the world in the first months of this year won't get money for them now. Instead, they'll likely get $500 credits next year when they file their 2020 taxes.

Craig Schoenberger and his wife had their first child, Aaron, in February. He said they're finding that the pandemic is driving up prices for things like baby wipes and diapers.

"He has a Social Security number now. In some branch of the government, he does exist. But I guess as far as the stimulus package, he doesn't exist," Schoenberger said.

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High earners who lost their jobs

The size of the payments starts scaling down for those who made more than $75,000 last year and zeroes out at $98,000 or more.

But what if you exceeded the limit in 2019 only to lose your job or get a lower-paying job this year? You won't get a payment now, but you will get a credit on your taxes next year when the system catches up.

Parents who split custody

Some parents who aren't married and split custody of their kids take turns each year claiming them on their taxes. Because the payments go off your 2019 tax return, whoever has the even years is out of luck.

Recently divorced or estranged

Not everyone who filed taxes jointly with a spouse in 2019 is still married to that spouse — or on speaking terms.

Couples who filed their taxes jointly last year get a single, combined payment of up to $2,400. The funds will be deposited into whatever bank account was used to deposit your most recent tax refund, unless you update your direct deposit information with the IRS. But there's no system to inform the IRS that you have divorced or are estranged.

People who owe back child support

The stimulus law puts on hold other debts that typically lead to tax refunds' being garnished, such as overdue student loans or back taxes. But not child support. The coronavirus money can still be garnished if you're overdue on those payments.

Lydia Carloni said she and her partner, Steve, have had their hours cut because of the coronavirus. She said her partner owes back child support from about a decade ago but pays it back in weekly installments.

She said not getting the full coronavirus payment means she'll be short on "a huge chunk of my rent."

"That's exactly what I was planning on," Carloni said. "I'm getting ready to pay this month's rent. Now I've got it. I'm not going to have it next month."