The chairman of the Hawaii Labor Relations Board, citing "serious concerns" about the Hawaii State Teachers Association’s challenge to its impartiality, has called a hearing Thursday to listen to the union’s claims before proceeding with the HSTA’s main prohibited practices complaint against the state over an imposed two-year contract.

James Nicholson, the board’s chairman, said today that the issue of the board’s impartiality was of such importance that it needed to be aired before proceeding with the broader complaint.

The teachers union has filed a complaint with the state Ethics Commission alleging that a letter Gov. Neil Abercrombie sent to the board last week about mediation may have improperly influenced the board.

The teachers union has challenged the Abercrombie administration’s decision to impose its "last, best and final" contract offer on teachers.

The labor board was expected to hear arguments surrounding the prohibited practices complaint today.