A new state audit of Medicaid spending by the Oregon Health Authority is nothing short of jaw-dropping.

The OHA has misspent millions of federal dollars and it doesn’t know how bad it really is. It has gaps that allow millions in improper payments to get through and lacks sufficient ways to detect them.

If that isn’t bad enough, it means that when the Legislature was crafting $300 million in new taxes for Medicaid funding, the needed tax increase was vastly overestimated. The audit should give voters no doubt that they should block that tax and vote no in January against Measure 101.

Medicaid is among the most complicated federal programs. Across the country, the federal government estimates 10 percent of Medicaid is improperly spent — including underpayment, overpayment, waste, fraud and abuse. Oregon’s decision to provide much of that federal care through 16 regional coordinated care organizations is in some ways a good thing. It provides more regional control of health spending, and CCOs have improved care according to some metrics.

But the use of CCOs also makes managing health care dollars more complicated for the OHA. Each of the 16 CCOs does things its own way. Some CCOs do not even try to track improper spending. Some have documented compliance issues. And because of the way the state contracts are written with CCOs, compliance problems are not linked with sanctions.

Other examples of problems from the audit are just as frustrating. For instance, OHA has some procedures to try to catch improper payments. The state auditors found, though, that several of them were effectively turned off. And the OHA didn’t periodically retest them to ensure they were working properly. The result is millions of tax dollars at risk.

While state auditors praised OHA’s new administration for its transparency and willingness to improve, that wasn’t the case before the new administration was appointed by Gov. Kate Brown in September. The previous administration at OHA did things like block direct access to staff, and take months to comply with requests for information. In one case, a squad of OHA management followed a state auditor around as the auditor was trying to work.

Before any new state tax pours hundreds of millions more into OHA, the Legislature needs to ensure OHA has its act together. Vote no on Measure 101.