If all parties to a dispute agree to submit their dispute to arbitration, mediation or conciliation, the neutral who serves in that process cannot be subpoenaed or otherwise compelled to disclose information gained in the setting up or conducting of the dispute resolution process. All communication made during the process shall be considered confidential.
Missouri Statute 435.014: Arbitrators, may not be subpoenaed--proceedings regarded as settlement negotiations, communications confidential.
Missouri General Assembly. Aug. 1, 1986http://revisor.mo.gov/main/OneSection.aspx?section=435.014&bid=24211&hl=