A Hawaii Government Employees Association unit that represents professional and scientific employees has rejected a two-year contract offer from the state.

The union announced Tuesday evening that 55 percent of the 8,100 worker unit voted against the offer. The unit will move to binding arbitration.

The HGEA’s bargaining team had not recommended the offer but allowed workers to vote.

The offer, according to the union, included roughly 4 percent annual pay raises. Workers would have paid a 40 percent share of their health insurance premiums, down from 50 percent.

Other HGEA units had received and ratified similar contract offers.