An estimated one quarter of retirees who may be eligible for economic stimulus payments of at least $300 each have not applied, including roughly 25,000 people in Allegheny County.

There are so many retirees apparently unaware they are entitled to the money that the Internal Revenue Service is reaching out with another reminder. The agency will send a second set of letters later this summer to roughly 5.2 million retirees and recipients of veterans benefits explaining how to make a claim. The letters will include a sample tax form plus an actual form people can complete and mail to the IRS.

The payments are part of the federal government's effort to stimulate the sagging economy. So far, roughly 76 million of 124 million eligible households have received their payments, the IRS said.

The payments are going out automatically to eligible taxpayers when they file their 2007 federal income tax returns this year. But even people who don't owe any income taxes, such as many Social Security recipients, may be eligible for the payments. The catch is that they have to go through the motions of filing a tax return to get the money.

"Some retirees and others who normally do not file a tax return may be eligible and not know it," said IRS Commissioner Doug Shulman. "If you know of a retiree or disabled veteran who might qualify, please pass along the information to them," he said.

People who don't earn enough money to pay federal income taxes, but make at least $3,000 -- including people whose only income is from Social Security or veterans disability payments -- can qualify for the minimum $300 per individual and $600 per married couple.

The types of Social Security benefits that qualify include retirement, disability and survivor payments. Supplemental Security Income does not qualify.

The payments should have no impact on other federal benefits currently being received, and are not taxable by the federal government or the state of Pennsylvania.

The filing deadline for claiming the money is Oct. 15.

People who don't normally file a return should use Form 1040A, available at www.irs.gov.

Low-income and elderly filers can get free assistance through the Volunteer Income Tax Assistance program (call 1-800-906-9887 to locate the nearest VITA site) and through an AARP Tax Aide site (1-888-227-7669.)

In addition, IRS taxpayer assistance centers offer in-person assistance. Area offices are at 1000 Liberty Ave., Downtown (412-395-5667); 4314 Old William Penn Highway, Monroeville (412-856-1913); and 162 W. Chestnut St., Washington, Pa. (724-229-5985).