MONTPELIER, Vt. – State officials on Tuesday were defending the law setting up the new Vermont health care exchange against charges from critics – including a U.S. House committee – that it violates the spirit, and perhaps the letter, of the federal Affordable Care Act.

At issue is a Vermont state law that says starting next year, individuals and businesses with up to 50 employees have to get their health insurance through the state exchange.

The House Oversight and Government Reform Committee wrote on Friday to Mark Larson, commissioner of the Department of Vermont Health Access, to say it appeared that requiring enrollment in the exchange violated the federal law.

“We are concerned this requirement will result in reduced consumer choice and higher costs for many businesses and individuals,” the letter said. “We are also concerned that the requirement conflicts with the text of (the ACA) that requires participation in the Exchange to be voluntary,” it continued.

The letter referred to a section of the law saying “nothing in this (law) shall be construed to prohibit” health insurance companies from selling plans outside the exchange, or individuals and businesses from buying them.

State officials pointed to the next paragraph in the same section of the ACA to make the case that while the federal government promises in the law not to bar health insurance outside the exchange, states are free to take that step within their own borders.

It says, “Nothing in this title shall be construed to terminate, abridge or limit the operation of any requirement under state law with respect to any policy or plan that is offered outside of the Exchange to offer benefits.”