Six states filed a new lawsuit Wednesday against the Obama administration over the Affordable Care Act.

The complaint that Texas, Wisconsin, Kansas, Louisiana, Indiana and Nebraska filed in the Northern District of Texas takes issue with the Health Insurance Providers Fee assessed to health insurers to cover federal subsidies.

The lawsuit says nothing in the Affordable Care Act’s language provided clear notice that states would also have to pay the fee.

“This notice was not even provided by rule but was ultimately provided by a private entity wielding legislative authority,” the suit says.

N.C. Insurance Commissioner Wayne Goodwin this week became the latest public official to warn of the harms wreaked by the Affordable Care Act, saying the federal insurance law has destabilized the state’s insurance market and now threatens to leave some residents without options for health insurance.

Goodwin expressed his concerns in a letter sent Tuesday to Sylvia Burwell, secretary of the U.S. Department of Health and Human Services, as a follow-up to a personal conversation he had with the Obama administration official in November. Goodwin, a Democrat up for re-election this year, warned that the ACA is driving up insurance costs, reducing consumer options and generating unsustainable financial losses for the insurers, with the potential risk that insurers will withdraw from the state altogether.