46 CFR § 150.150 - Exceptions to the compatibility chart.
The Commandant (CG-ENG-5) authorizes, on a case by case basis, exceptions to the rules in this subpart under the following conditions:
(a) When two cargoes shown to be incompatible in Figure 1 meet the standards for a compatible pair in Appendix III, or
(b) When two cargoes shown to be compatible in Figure 1 meet the standards for an incompatible pair in Appendix III.
Appendix I contains cargoes which have been found to be exceptions to Figure 1, the Compatibility Chart.