IME filed comments supporting PHMSA’s rulemaking initiative, HM-233D, to incorporate operating standards for multi-purpose bulk trucks (MBT) and cargo tanks that transport bulk explosives into the hazardous materials regulations. HM-233D is the outcome of a petition for rulemaking filed by IME based on industry standards contained in Safety Library Publication (SLP) 23. IME comments praise PHMSA for recognizing the proven safety of industry best practices for the transport of bulk explosives and the willingness of the agency to incorporate by reference SLP-23. IME disagrees with PHMSA’s proposals to install on new or modified MBTs unproven fire-suppression equipment and to double the number of automatic battery shut off switches when no incident has shown that the number of switches with enhance fire extinguisher capacity currently on bulk trucks is insufficient. IME looks forward to working with PHMSA to ensure the continued safe operation of bulk trucks.