(Bloomberg) -- The IRS still hasn’t found everyone who is due a $1,200 stimulus check from the government, and locating everyone eligible for the payments will be key for any additional pandemic relief Congress may pass later this year.

IRS Commissioner Charles Rettig told the Senate Finance Committee Tuesday that the agency was working with states and community groups to find individuals who are owed payments but aren’t connected to the tax system or a federal benefit program, such as Social Security.

The non-partisan Center on Budget and Policy Priorities estimates that about 12 million Americans are at risk of losing out on the stimulus checks that were created under economic relief plan passed by Congress. The group includes very low-income families, the homeless and the long-term unemployed, and they are disproportionately Black and Latino, according to the group.

Rettig said he was not “at liberty” to give a specific number, but said the 12 million was an significant overstatement.

“We can’t count people who we can’t identify,” he said. “We can’t issue payments to people who we can’t identify.”

The IRS has touted its success of quickly issuing the payments, sending about 160 million payments totaling $269 billion by mid June -- more than 90% of the money the federal government expects to distribute.

On top of that, the agency has processed 126 million individual tax returns and issued $257 billion worth of refunds, Rettig said.

He said finding those who have not yet received their payments, including those in under-served communities and people experiencing homelessness, is a priority for the agency.

The IRS’s ability to create a more comprehensive list of those eligible for the payments would make it easier for the IRS to issue another round of payments later this year. Lawmakers will begin debating an additional round of stimulus in mid-July. House Democrats, along with Treasury Secretary Steven Mnuchin and President Donald Trump, have expressed interest in sending more money to households.

The $2.2 trillion CARES Act passed in March included $1,200 payments for adults making up to $75,000, and $500 for their children. The payments phased out for those making up to $99,000, or twice that for a married couple.

Up to 450,000 payment recipients did not get the additional $500 per child they are owed, according to a Government Accountability Office report released last week. Rettig said the agency is working to issue those payments this summer.

©2020 Bloomberg L.P.