Labor Code § 5278
PART 3.5. ARBITRATION
(a) No disclosure of any offers of settlement made by any party shall be made to the arbitrator prior to the filing of the award.
(b) Article 7 (commencing with Section 11430.10) of Chapter 4.5 of Part 1 of Division 3 of Title 2 of the Government Code applies to a communication to the arbitrator or a potential arbitrator.