mental regulations. Changes in provisioning practices, such as switching from small to large ketchup bottles, also can have economic benefits.

The U.S. Navy collects a considerable amount and range of internal information, including data on ship garbage generation and management and the activities of the home ports that provide ships with supplies and services, including garbage disposal. In addition, the Navy has examined in depth its supply chain and the shipboard equipment options for treating garbage. The Navy's Annex V compliance plans also have been reviewed by the U.S. General Accounting Of-flee (1994a, 1994b), which has criticized the Navy's planning and the large sums of money spent on technology projects that have not been deployed to the fleet. Thus, the level of detail available concerning the Navy's garbage generation and disposal practices exceeds that obtained for other maritime sectors. At the same time, it can be difficult to make generalizations about the Navy, because compliance strategies are not necessarily the same for every ship. For example, recycling practices vary by operating unit (U.S. General Accounting Office, 1994b).

Little is known about garbage management practices of the commercial or foreign ports sometimes used by naval vessels, or the commercial waste haulers that some home ports may be forced by local laws to employ. The Navy does not report inadequate port reception facilities using the IMO forms because public vessels are exempt from MARPOL requirements.

The Navy's surface fleet is subject to direct federal control through both internal management practices and external congressional review. The Navy has an established command and control structure that has served as an effective mechanism for organizing fleetwide compliance with the MPPRCA. A range of interventions has been employed. Operational measures include the 3-day/20-day rule (described in Chapter 1) for holding plastics on board. The Navy supports its implementation efforts with a vigorous education program for ship and shoreside personnel (Koss et al., 1990; Koss, 1994) and an internal system of rewards and sanctions. (Violators have been punished [Ocean Science News, 1991].) Economic incentives include returning monies from recycling to ship crews.

Technical interventions are the key to full compliance in this sector. Federal control of progress in implementation currently is limited for very large ships, such as aircraft carriers, by both ship design and the need to undertake extended missions. Garbage cannot be treated adequately on these ships at present because

the equipment developed by Navy researchers has yet to be installed.¹² Part of the problem should be solved within several years. To comply with the 1988 MPPRCA deadline for halting overboard discharge of plastics, the Navy recently has focused its technical program on development of a shredder-heater-compactor system. The preproduction prototype was installed on an aircraft carrier in May 1994 and fleetwide installation is to be completed by late 1998.

But disposal of garbage other than plastics remains a problem. The Navy must operate in Annex V special areas, where no garbage except food waste may be discharged overboard. At present, this requirement is not causing major difficulties, because the Navy conducts few activities in the three special areas now in force (the Baltic and North seas and the Antarctic Ocean). However, the Navy must prepare for the entry into force of special area requirements in the Mediterranean, Gulf of Mexico, and elsewhere, where its operations are extensive. The Navy sought legislation that would have allowed its vessels to discharge pulped or shredded nonfood garbage in special areas, but the Congress did not authorize this change. As a result, the Navy has suspended plans to purchase and install pulpers and shredders¹³ (the shredder technology now is used in the plastics processor).

While acknowledging that use of pulpers and shredders would be beneficial outside special areas (e.g., it would diminish evidence signaling vessel whereabouts to potential enemies and eliminate ''aesthetically objectionable discharge of intact trash''), the Navy has determined it is not worth spending several hundred million dollars to retrofit ships with equipment that would not enable compliance with special area requirements (U.S. Navy, 1994). Instead, to meet these requirements, the Navy plans to solicit proposals from industry for technologies suitable for shipboard use. The Navy also is experimenting with several advanced garbage treatment technologies not included in its formal plan.¹⁴