Ten states plus the District of Columbia haven't yet received federal approval to offer unemployed workers an extra $300 a week in benefits.
Delaware, Illinois, Kansas, Nebraska, Nevada, New Jersey, North Dakota, South Carolina, Washington, D.C., and Wisconsin haven't yet received federal approval. South Dakota's governor said the state won't apply for the subsidy.
Meanwhile, at least six states have begun paying the supplement.
President Trump signed an executive measure creating the Lost Wages Assistance program more than three weeks ago.
The program offers workers $300 a week on top of current benefits. (States may opt to kick in an additional $100 a week, but few have chosen to do so.)
It has been slow to roll out, at a time when unemployed workers haven't received a prior $600 weekly enhancement for about a month.
States must apply for and receive federal approval to pay the lost wages assistance.
To date, 40 states have received approval. Florida, Hawaii and Minnesota, were the latest to get approval, over the weekend.
Arizona, Louisiana, Missouri, Montana, Tennessee and Texas are the first states to disburse the aid. Montana is paying $400 a week, while the others are paying $300.
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States get an initial tranche of funding for three weeks of unemployment, covering the weeks ended Aug. 1 through 15. They must then apply weekly for additional funding.
The program will pay up to $44 billion in total federal disaster-relief funds to unemployed workers.
Arizona, Louisiana and Missouri were among the first states to receive federal approval for the lost wages assistance, almost two weeks ago. Texas followed shortly thereafter.
Arizona planned to complete all retroactive payments last week, according to the state's Department of Economic Security website.
Texas paid out more than $424 million last week, out of its total $1.38 billion in approved funding, according to spokesman Francisco Gamez, spokesman for the state Workforce Commission.
Louisiana paid out $240 million to almost 300,000 eligible workers on Wednesday, according to a statement from the state's Workforce Commission.
Tennessee started issuing the aid Wednesday, according to Chris Cannon, spokesman for the Department of Labor and Workforce Development. The state received $236 million in initial funding.
Missouri began processing the $300 federal supplement Tuesday night and workers should "soon" start receiving payments, according to a statement from the Missouri Department of Labor and Industrial Relations.
The state was approved for $200 million in total funding for roughly 100,000 eligible workers, according to the statement. It expected to issue the first retroactive payment by the end of last week, while the rest should be received by the end of this week.
A spokeswoman for the Federal Emergency Management Agency, which is overseeing funding for the lost wages assistance program, declined to say whether additional states had begun disbursing the aid.
It may be several weeks before many other states start making payments, due largely to administrative challenges.
The Colorado Department of Labor and Employment estimates payments won't arrive until mid- to late September, for example.
Alaska believes it will take six to eight weeks to reprogram changes in the state's technology systems necessary to disburse the aid, according to Cathy Munoz, deputy commissioner of the state's Department of Labor and Workforce Development.
A $600 weekly federal supplement ended in July after Congress couldn't agree on the structure of additional relief. Around 27 million workers were collecting unemployment benefits as of early August.
Unemployed workers will likely get about four or five weeks' worth of the financial assistance, depending on how many states participate and how quickly they draw down the $44 billion funding allocation, FEMA officials estimate.
But program parameters leave open the possibility that workers wouldn't get more than the minimum three weeks. Payments would cease if FEMA's Disaster Relief Fund — the same pot of money used for weather-related and other disasters — dips below $25 billion.
With wildfires raging in California and the destruction left behind by Hurricane Laura, a Category 4 storm that made landfall last week in Louisiana, some fear the fund could be depleted before the full $44 billion is paid out.
That's unlikely to occur, according to Sarah Miller, a lecturer in emergency and disaster management at Georgetown University.
"I think unemployment benefits are safe for now," said Miller, a former emergency manager for the city of Auburn in Washington state.
The fund had about $74 billion at the beginning of August. Congress could allocate more money to the fund come Oct. 1, which marks the start of the government's new fiscal year, Miller said.