About 16,000 Minnesotans who applied for Medical Assistance through MNsure are still without health insurance, some caught in limbo for as long as six months.

State officials said Wednesday that letters notifying consumers of problems with their original insurance applications never got sent out. That mistake meant consumers didn't realize they still had to provide crucial information before they could get coverage.

"It was a serious error on our part of not being more on top of understanding that process, and having the oversight in place," said Deputy Commissioner Chuck Johnson of the Minnesota Department of Human Services.

The process, which was intended to be fully automated, still relies on one of the many manual workarounds holding the MNsure system together. An upgrade to the MNsure system later this month is expected to fully automate the process.

Problems with mailing the letters were first discovered in early January, and were believed to have been resolved. But the agency didn't have the right project management in place to catch continuing issues, Johnson said. Officials discovered late last week that many people still hadn't been notified that their applications were incomplete.

More than 149,000 low-income Minnesotans have used MNsure to sign up for Medical Assistance. But many of those still waiting for approval were flagged because the state needed to get additional information such as verifying income, citizenship, tribal membership or Social Security.

The situation represents the latest misstep by state officials striving to get coverage for as many people as possible, particularly low-income Minnesotans and their families.

The reliance on manual workarounds and a lack of oversight and project management were identified as key ongoing issues in recent reports by outside reviewer Deloitte Consultants. MNsure officials decided last month to focus on improving the current system for this fall's open enrollment period before making a decision about whether it ought to be saved or scrapped in the long haul.

Commissioner Lucinda Jesson of the Department of Human Services notified directors at county human services offices of the problem in an e-mail Wednesday. Letters to Minnesotans still without insurance are expected to go out by mid-July, according to the e-mail, and the state will work with insurers to guarantee coverage back to the original application date.

Jesson also asked that county workers "redouble their efforts, as soon as possible" to contact Minnesotans in need.

Many county workers already are overwhelmed trying to work through the backlog of pending cases as well as get new people enrolled in coverage.

Deborah Huskins, director at the Hennepin County human services and public health office, estimates that the state already has identified 6,000 unresolved cases. She worries that her staff will hear from confused citizens whose cases have already been resolved.

"The problem is that it adds onto a whole pile of things that aren't going well in our ability to help our clients," she said. "This is one more sign of a lack of a good, functioning system. To the extent that there's confusion … the county worker is bearing the brunt of customer dissatisfaction."

But Huskins, who was able to hire 75 additional people last year, said despite the frustration, front-line workers tell her this is "historic and complex, and it won't be implemented overnight."

"They're focused on the prize of helping people get the health care coverage to which they're entitled," she said. "And when that happens it's a good thing."