Kevin Sullivan, the state commissioner of revenue services, issued a public apology Friday for an agency error that caused about 120,000 taxpayers to overstate the value of a property tax credit, resulting in about $12 million in underpayments to the state.

The goof means lots of taxpayers can expect a letter telling them they'll need to return a portion of their refund.

"When we make a mistake, we own it and fix it immediately," Sullivan said.

A statement about the apology went out at about 4:30 p.m., three hours after Rep. Vincent J. Candelora, R-North Branford, issued a news release publicizing the error.

“The incompetence in state government has seeped down to the roots,” Candelora said. “This tax change was a poor decision to begin with, but now to have surprise tax bills going out to people after they have paid their taxes is going to be very upsetting.”

Sullivan said the department failed to inform taxpayers of a legislative change in 2015 that lessened the value of property tax credits. The mistake involved directions for taxpayers who file jointly or separately as heads of households.

"Affected taxpayers who have already received refunds or whose tax payments were completed before the error was discovered will be notified in writing by DRS. Those with a resulting underpayment will be billed without penalty or interest for the balance," Sullivan said.

Senate Minority Leader Len Fasano, R-North Haven, said the mistake was emblematic.

“The confusing fiscal policies passed by the Democrats in rushed budget packages in the middle of the night are apparently not only confusing to the public, they’re confusing to the governor’s own tax agency!" Fasano said in a written statement. "This is an embarrassment that shows Connecticut government in a state of disorder and chaos."

Mark Pazniokas is a reporter for The Connecticut Mirror (www.ctmirror.org). Copyright 2016 © The Connecticut Mirror.

mpazniokas@ctmirror.org