More than 300,000 people who haven’t documented their citizenship or legal residency in the U.S. face a Sept. 5 deadline to prove their eligibility or lose their Obamacare health coverage, the government said.

In May, the U.S. said about 1 million people who signed up for private health plans under the Patient Protection and Affordable Care Act lacked proof that they are citizens or legal residents. Since then, about 660,000 have documented their eligibility for the program or are doing so, the Centers for Medicare and Medicaid Services said today in a statement.

About 8 million people signed up for plans using new health insurance exchanges by April, when the law’s first enrollment period closed. Those who fail to prove their eligibility will lose coverage on Sept. 30, the government said.

“We want as many consumers as possible to remain enrolled in marketplace coverage, so we are giving these individuals a last chance to submit their documents before their coverage through the marketplace will end,” Marilyn Tavenner, the CMS administrator, said in the statement.

Another 1 million people who signed up for coverage hadn’t verified their incomes by May, the government said. Eligibility for subsidies to help buy coverage is based on income. CMS didn’t say how many of those cases have been cleared up, and no deadline has been set to cancel their coverage. They “will hear from the marketplace at a later date,” the agency said in the statement.

Aaron Albright, a spokesman for CMS, said he had no information on the status of people who hadn’t verified their income.

Eligibility Rules

Those residing in the U.S. illegally aren’t eligible for Affordable Care Act coverage. Legal residents who understate or lie about their incomes may remain eligible, while losing all or part of U.S. subsidies to help pay their premiums.

It’s not clear how many of the 8 million who signed up for health plans by April are still enrolled. The Obama administration stopped issuing monthly enrollment reports in May and isn’t scheduled to provide an update until December.

Republicans on the House Energy and Commerce Committee said today that only about 80 percent of people who signed up for plans ever paid their first monthly premium, the final step in enrollment. The Republicans surveyed insurers participating in the federal exchange to obtain the figure. If accurate, that would reduce total enrollment to about 6.4 million.

The Obama administration hasn’t said how many people paid their first premium to allow their coverage to take effect.

‘Gone Silent’

“The White House that once proudly trumpeted transparency has now gone silent when it comes to how the president’s health law is actually working,” U.S. Representative Fred Upton, the Michigan Republican who chairs the committee, said in a statement. “While the Obama administration was quick to celebrate the end of the first open enrollment period, the reports have since disappeared.”

In addition to enrollment in private plans, about 7.2 million people gained coverage through Medicaid since the law expanded the government’s program for the poor this year, Tavenner’s agency said Aug. 8.