On January 23, 2014 (80 FR 3788), the Pipeline and Hazardous Materials Safety Administration (PHMSA) published a notice of proposed rulemaking (NPRM) in the federal register to amend the Hazardous Materials Regulations (HMR) contained in 49 CFR Parts 171 – 180. The purposes of this NPRM are update and clarify the HMR based on PHMSA’s own initiatives. The proposed changes were identified through an extensive review of the HMR and letters of interpretation issued to the public. In addition, this NPRM proposes regulatory requirements that respond to seven petitions for rulemaking and addresses two National Transportation Safety Board (NTSB) Safety Recommendations. To this end, PHMSA is proposing to revise, clarify, and ease certain regulatory requirements. The proposed provisions in this rulemaking include, but are not limited to, removing the packing group (PG) II designation for certain organic peroxides, self-reactive substances and explosives, incorporating requirements for trailers of manifolded acetylene cylinders, and providing requirements to allow for shipments of damaged wet electric batteries. In addition, this rulemaking proposes to revise the requirements for the packaging of nitric acid, testing of pressure relief devices on cargo tanks, and shipments of black or smokeless powder for small arms. Comments must be received by March 24, 2015.