Refunds totaling more than $1.1 billion may be waiting for nearly 1.1 million people nationwide who did not file a federal income tax return for 2007, the Internal Revenue Service announced Monday.

In Alabama alone, $15.65 million in refunds may be waiting for 17,600 people.

To collect the money, a return for 2007 must be filed with the IRS no later than Monday, April 18, 2011.

The IRS estimates that half of these potential 2007 refunds are $640 or more. In Alabama, half of the refunds are $634 or more.

Some people may not have filed because they had too little income to require filing a tax return even though they had taxes withheld from their wages or made quarterly estimated payments. In cases where a return was not filed, the law provides most taxpayers  a three-year window of opportunity for claiming a refund. If no return is filed to claim a refund within three years, the money becomes property of the United States Treasury.

For 2007 returns, the window closes on April 18, 2011. The law requires that the return be properly addressed, mailed and postmarked by that date. There is no penalty for filing a late return qualifying for a refund.

The IRS reminds taxpayers seeking a 2007 refund that their checks will be held if they have not filed tax returns for 2008 and 2009. In addition, the refund will be applied to any amounts still owed to the IRS, and may be used to offset unpaid child support or past due federal debts such as student loans.

By failing to file a return, people stand to lose more than a refund of taxes withheld or paid during 2007. Furthermore, many low-and-moderate income workers may not have claimed the Earned Income Tax Credit (EITC). The EITC helps individuals and families whose incomes are below certain thresholds, which in 2007 were $39,783 for those with two or more children, $35,241 for people with one child and $14,590 for those with no children.

For more information, visit the EITC Home Page.

Current and prior year tax forms and instructions are available on the forms and publications page of IRS.gov or by calling toll-free 1-800-TAX-FORM (1-800-829-3676).

Taxpayers who are missing Forms W-2, 1098, 1099 or 5498 for 2007, 2008 or 2009 should request copies from their employer, bank or other payer. If these efforts are unsuccessful, taxpayers can get a free transcript showing information from these year-end documents by calling 1-800-908-9946, or by filing Form 4506-T, Request for Transcript of Tax Return, with the IRS.