(a) When a person is approached in connection with his or her possible appointment as an arbitrator, that person shall disclose any circumstances likely to give rise to justifiable doubts as to his or her impartiality or independence. An arbitrator, from the time of his or her appointment and throughout the arbitral proceedings, shall without delay disclose any of these circumstances to the parties unless they have already been informed of them by the arbitrator.
     (b) An arbitrator may be challenged only if circumstances exist that give rise to justifiable doubts as to his or her impartiality or independence or if he or she does not possess qualifications agreed to by the parties. A party may challenge an arbitrator it has appointed, or in whose appointment it has participated, only for reasons of which that party becomes aware after the appointment has been made.