The historical practice of bulk dry cargo vessels on the Great Lakes is to discharge cargo residues ("dry cargo residue" or DCR) overboard. Dry cargo residue is cargo that remains on the deck or cargo spaces after loading or unloading operations. Generally, these residues include limestone and other clean stone, iron ore (such as taconite), coal, salt, and cement. These substances are primarily inorganic, non-toxic, and non-hazardous. Public Law 108-293, sec. 623(b), gives the Coast Guard regulatory authority over DCR discharges in the Great Lakes. An Interim Rule (73 FR 56492, Sep. 29, 2008) allows the discharge of bulk DCR in limited areas of the Great Lakes by self-propelled vessels and by any barge that is part of an integrated tug and barge unit. A Supplemental Notice of Proposed Rulemaking (SNPRM), (77 FR 44528, July 30 2012), proposed replacing its existing interim rule with a new rule and also announced the availability of a tiered Draft Environmental Impact Statement (DEIS) prepared in support of the SNPRM. The SNPRM proposed to allow the discharge of DCR in limited areas of the Great Lakes. However, vessel owners and operators would need to minimize DCR discharges using methods they would be required to document in DCR management plans. The SNPRM also proposed to prohibit limestone and clean stone discharges in some waters where they are now permitted.