SAN FRANCISCO (AP) – Ernesto Cuellar filed his taxes this year not just to report what he made from his $9-an-hour job as a house painter, but also, he hopes, to speed his path to becoming a legal resident of the United States.

Cuellar submitted his federal return using an increasingly popular tax number issued by the Internal Revenue Service to people who can’t get Social Security numbers. Many, like Cuellar, are undocumented immigrants, causing concern among critics of U.S. immigration policy.

“By paying taxes, the government will be able to see that immigrants are contributing to the economy,” said Cuellar, 35, who came from Mexico almost five years ago and now lives in San Francisco. “That record will hopefully help me in the future, as proof that I’ve been complying and filing” taxes.

The IRS has issued more than 6.8 million of the individual taxpayer identification numbers since 1996. Last year, it gave out almost 1.5 million, about 58 percent more than in 2000.

The government doesn’t track how many undocumented immigrants have been issued the nine-digit numbers, and officials note that not everyone who seeks one is undocumented. Some are foreign students or researchers who are in the country under temporary, legal visas. By law, the agency is barred from routinely sharing data on taxpayers with federal immigration officials.

At the Midwest Tax Clinic in Chicago, director Salvador Gonzalez said about 150 people have come in and applied for the numbers in the last two years. Another 1,000 have applied at churches and community centers where the clinic reaches out to local residents.

“A lot of people, they want to become bona fide taxpayers,” Gonzalez said.

The tax numbers also are being used for purposes beyond their original intent, to help people open bank accounts and get driver’s licenses in some states.

That’s put the IRS numbers in the middle of a debate over what to do about the estimated 9 million undocumented immigrants living in the United States. Advocates say allowing them to get financial services and drive legally makes communities safer for everyone. But critics argue the tax number just makes it easier for illegal immigrants, who shouldn’t be in the United States in the first place, to meld into society.

Marti Dinerstein, president of the New York-based public policy firm Immigration Matters, said the numbers should be used for tax purposes only.

“I really don’t think it is a smart thing for local and state governments to make it easier for illegal immigrants to reside and work and therefore stay in the United States,” Dinerstein said. “It shows a total disrespect for the laws of the United States.”

About 366,000 returns were filed using individual taxpayer identification numbers in 2001, according to IRS data from that year, the most recent information available. People with the tax numbers reported wages of almost $7 billion and paid almost $305 million in taxes, according to the IRS.

Wells Fargo Bank, Citibank and Washington Mutual already accept the numbers from people who want to open bank accounts.

“You’ve got undocumented workers here. Let’s face it, they’re going to be here and they take the jobs that no one else wants,” said Chi Chi Wu, staff attorney at the National Consumer Law Center. “If they’re going to be here, we’d rather have them in bank accounts than carrying around a lot of cash and being targeted for robbery and theft.”

Wu hopes the IRS number will be used in the future to help make more financial services, such as mortgages or other loans, available to undocumented immigrants.

Utah, Rhode Island and North Carolina are among the states that accept the tax number from people applying for driver’s licenses, and New Mexico recently passed a law to accept it starting this summer. Similar proposals are being considered in California and Illinois.

The number’s popularity indicates how the nation’s immigration policies have failed, said Michele Waslin, senior immigration policy analyst at the National Council of La Raza, a Hispanic advocacy group.

“Really, what banks and state and local governments have had to do is come up with creative solutions dealing with people who are living in the community,” she said.