Numerous types of impact-producing factors were identified that warrant detailed analysis. Each type is incorporated into six discrete oil and gas exploration, production, and transportation scenarios that are analyzed for possible impacts. All of the following impact-producing factors are included in the scenarios for the proposed action, alternatives, and cumulative analysis. In addition, the scenario for the cumulative impact analysis includes activities unrelated to OCS development but relevant to assessing cumulative impacts. See sections IV.D.1.a, IV.D.2, IV.D.3, IV.D.4, and IV.D.5 for proposed action and alternative scenarios, and section IV.D.1.b for the cumulative scenario.

- Accidental oil spills including those from well "blowouts," production accidents, and transportation system (e.g., tankers vessels, and seafloor pipelines) failures.

- Liquid waste disposal including well drilling fluids, produced water, and domestic wastewater generated at offshore facilities. The issue of disposing naturally occurring radioactive material (NORM) is often raised in the context of liquid waste disposal because NORM sometimes is entrained in the water produced along with oil and gas.

Gaseous emissions from offshore and onshore facilities and transportation vessels and aircraft.

- Traffic including oil tankers and barges, and crew, supply, and seismic survey vessels and aircraft.

Solid waste disposal including material removed from the wellbore (i.e., drill cuttings), solids produced with the oil and gas (e.g., sands), and trash and debris (e.g., equipment or tools) accidentally lost.

Installing and removing or decommissioning equipment including offshore platforms, seafloor pipelines, and onshore processing facilities.

In addition to the activities that might result from the proposed action, the EIS analyzes natural phenomena that might cause indirect impacts by affecting the safe conduct of OCS oil and gas exploration, production, or transportation activities. The following phenomena are among those addressed in Section IV.C of the EIS.

Physical oceanographic processes including water currents, sea ice, and waves.

For each resource or resource group covered in detail in the EIS, six specific analyses are presented. This includes one for the proposed action, one for each of the four alternatives, and one for the cumulative scenario. In addition to these scenario-specific analyses, a generic impact analysis for each resource or resource group is included in section IV.A. A discrete analysis of potential OCS program impacts on global climate change is included in section IV.B.2.

- Water quality including marine and estuarine areas. The water quality issues raised are related primarily to marine water quality and were generally raised in the context of how changes in water quality caused by OCS activities could affect biological resources, especially fisheries. See EIS sections IV.D.1.a(1), IV.D.1.b(1), IV.D.2(1), IV.D.3(1), IV.D.4(1), and IV.D.5(1) for scenario specific analyses.

Air quality. The principal concern identified with respect to air quality is the possible effects of offshore emissions on onshore air quality, and the potential for offshore emissions to contribute to violations of onshore air quality standards. See EIS sections IV.D.1.a(2), IV.D.1.b(2), IV.D.2(2), IV.D.3(2), IV.D.4(2), and IV.D.5(2) for scenario specific analyses.

Issues raised regarding possible impacts on biology and ecology fall into three main categories: animals (including threatened and endangered species); plants; and habitats or ecological systems. Among the animal groups identified as needing analysis for potential program impacts were marine mammals (e.g., whales, seals, and sea lions), birds (e.g., waterfowl, seabirds), fish/shellfish (e.g., salmon, oysters), and sea turtles. Seagrass was the only plant species specifically identified as being potentially affected by activities associated with the proposed action. With respect to habitats or systems, both marine (i.e., sanctuaries, marine parks/preserves, and "hard bottom" areas), and coastal (i.e., estuaries, wetlands/marsh, intertidal zone, seashore parks) areas were identified as subject to possible adverse impacts. The specific biological and ecological resources analyzed in detail are listed below.

Marine mammals including a variety of endangered and non-endangered cetaceans (whales), pinnipeds (seals, sea lions, walruses), sea otters, and polar bears. See EIS sections IV.D.1.a(3), IV.D.1.b(3), IV.D.2(3), IV.D.3(3), IV.D.4(3), and IV.D.5(3) for scenario specific analyses.

Terrestrial mammals including caribou and three species of mice that inhabit certain coastal areas of the GOM. See EIS sections IV.D.1.a(4), IV.D.1.b(4), IV.D.2(4), IV.D.3(4), IV.D.4(4), and IV.D.5(4) for scenario specific analyses.

- Birds including a variety of endangered and non-endangered seabird, shorebird, waterfowl, and raptor species. See EIS sections IV.D.1.a(5), IV.D.1.b(5), IV.D.2(5), IV.D.3(5), IV.D.4(5), and IV.D.5(5) for scenario specific analyses.

Fish including a variety of finfish and shellfish species used for commercial or recreational purposes. See EIS sections IV.D.1.a(6), IV.D.1.b(6), IV.D.2(6), IV.D.3(6), IV.D.4(6), and IV.D.5(6) for scenario specific analyses.

Reptiles limited to sea turtles. See EIS sections IV.D.1.a(7), IV.D.1.b(7), IV.D.2(7), IV.D.3(7), IV.D.4(7), and IV.D.5(7) for scenario specific analyses.

- Coastal habitats including barrier islands, estuaries, seagrass beds, and wetlands. See EIS sections IV.D.1.a(8), IV.D.1.b(8), IV.D.2(8), IV.D.3(8), IV.D.4(8), and IV.D.5(8) for scenario specific analyses.

- Seafloor habitats including submarine canyons, topographic highs, and "live bottom" areas. See EIS sections IV.D.1.a(9), IV.D.1.b(9), IV.D.2(9), IV.D.3(9), IV.D.4(9), and IV.D.5(9) for scenario specific analyses.

Coastal and marine parks, refuges, and sanctuaries including national parks, seashores, recreation areas, wildlife refuges, and marine sanctuaries. For potential impacts, refer to the analyses for the particular environmental, social, or cultural resources associated with a particular site.

Concerns about the possible socioeconomic impacts of implementing the proposed action were identified more often than any other type of analytical issue. Specific concerns included potential impacts on tourism, commercial fishing, aesthetics, local economy (especially the "boom/bust" phenomenon), and recreation. The need to include an assessment of the potential effects of the proposed action on minority communities and low-income populations also was identified. Consideration of the latter issue is required by the President's Executive Order on Environmental Justice (E.O. 12898). The EIS must identify and address disproportionately high and adverse human health and environmental effects of the proposal on low-income populations and minority communities (Native American included).

Coastal communities including population, employment, land use, and public services. See EIS sections IV.D.1.a(10), IV.D.1.b(10), IV.D.2(10), IV.D.3(10), IV.D.4(10), and IV.D.5(10) for scenario specific analyses. These sections also contain analyses of the potential effects of the proposed program on the socio-cultural systems of Alaska Natives. They respond, in part, to the need to address the issue of environmental justice.

Fisheries, both commercial and recreational. See EIS sections IV.D.1.a(11), IV.D.1.b(11), IV.D.2(11), IV.D.3(11), IV.D.4(11), and IV.D.5(11) for scenario specific analyses.

- Subsistence hunting and fishing activities. This analysis focuses on the potential effects of the proposed program on traditional hunting and gathering activities of Alaska Natives. See EIS sections IV.D.1.a(12), IV.D.1.b(12), IV.D.2(12), IV.D.3(12), IV.D.4(12), and IV.D.5(12) for scenario specific analyses. These analyses respond, in part, to the need to address the issue of environmental justice.

Archaeological resources including historic shipwrecks and sites inhabited by humans during prehistoric times. See EIS sections IV.D.1.a(13), IV.D.1.b(13), IV.D.2(13), IV.D.3(13), IV.D.4(13), and IV.D.5(13) for scenario specific analyses.

- Recreation and tourism including the use of coastal areas for sightseeing, beachcombing, observing wildlife, swimming, diving, surfing, sunbathing, hunting, fishing, and boating. See EIS sections IV.D.1.a(14), IV.D.1.b(14), IV.D.2(14), IV.D.3(14), IV.D.4(14), and IV.D.5(14) for scenario specific analyses.

Several suggestions were offered regarding the methods that should be used to analyze the potential impacts of the proposed action. The following suggestions regarding analytical methods are incorporated into the EIS.

Describing the existing environment. Characterize the environmental resources and existing uses of each planning area and adjacent coastal areas. Describe trends in uses and environmental conditions in the absence of the proposed action. The descriptions of the potentially affected resources presented in section III include these considerations.

Resource specific analyses. Distinguish between the impacts that would be expected if an environmental resource is exposed to oil from the impacts that are most likely considering the probability of oil spills occurring if the proposal is implemented. This suggestion reflects a concern

that the assessment of the potential impacts of spilled oil might be diminished if the likelihood of exposure to oil spills is low. To ensure that the distinction is made, this EIS includes two types of analyses related to spilled oil. First, a "generic" analysis is presented which describes the impacts of oil spills on all significant environmental resources that could be exposed to OCS oil and gas activities. Second, scenario-specific analyses describe the severity of potential impacts and also present the probability of oil spill occurrence in areas where particular environmental resources could be affected. The generic effects of spilled oil on each environmental resource are presented in section IV.A. The scenario-specific effects of oil on these resources as a function of spill probabilities are included in section IV.D.

Cumulative impact analysis. Cumulative impacts on a specific resource should be presented in a regional or national context. The cumulative impact analysis is prepared from a resource perspective rather than a geographic perspective. This allows an overall assessment of effects from each of the activities included in the cumulative scenario, regardless of where the activity occurs. This is particularly important for assessing potential impacts on species (e.g., gray whales) that migrate through more than one OCS planning area.

- Indian Trust Resources. Although it was not raised in the context of the 5-year leasing program, the issue of the potential impacts of OCS development on Indian trust resources has been raised during the development of leasing proposals for the Alaska OCS. This issue is not analyzed in detail in this EIS for several reasons. It is not expected that implementing either the proposed action or any of the alternatives would have significant effects on Indian trust resources. Further, the Federal Government does not recognize the validity of claims of aboriginal title and associated hunting and fishing rights that have been asserted for unspecified areas of the Alaska OCS. However, the EIS does analyze the potential impacts of the proposed 5-year leasing program on Native communities as they relate to economics, subsistence harvest patterns, and sociocultural systems.

- Human safety. Concerns about the safety implications of OCS oil and gas development were identified during scoping. This issue is not analyzed in detail because worker safety is more appropriately considered during the review of individual lease exploration and development proposals. The OCS Lands Act and the implementing regulations require that all drilling and production operations use the best available and safest technologies (BAST). A principal reason for requiring BAST is to minimize the adverse effects of OCS operations on human safety. It is during the review of proposals to conduct lease operations that MMS considers whether they would be conducted in a manner that conforms with the many specific requirements developed to protect human safety. The MMS can best determine at that time whether additional measures are needed to reduce the potential for accidents that affect safety.

Human health. With the possible exception of the improper onshore disposal of NORM, none of the activities associated with the proposed action were identified as having any potential for significantly affecting public health. The disposal of NORM is a concern in the GOM, and this concern is associated primarily with potential impacts on water quality. As such, it is addressed as part of the analysis included in sections IV.A.1.b(1)-Water Quality and IV.D.1.a.(1)(a)-Coastal Waters. As indicated in section IV.A.1.b(1), the issue of NORM disposal is currently under study. The results of this study and any potential human health effects will be included in the pertinent

environmental analyses that will be conducted for the specific leasing proposals that are evaluated as part of the 5-year leasing program for 1997-2002 that is ultimately adopted.

One of the analytical techniques suggested for use in the EIS was not adopted. A summary of the suggestion and the reasons for not adopting it are presented below.

3.

Resource specific analyses. Avoid the use of analyses that cover similar species in a single presentation with an overall impact conclusion. This suggestion was not adopted for two reasons. First, the potential impacts to similar animal species (e.g., diving ducks) are often estimated to be of a similar nature and magnitude. It would be redundant to present a duplicate analysis for each species in the group where differences in impacts cannot be distinguished. Second, any species specific deviation from the general group impact finding is clearly articulated in the analysis and conclusion presented for the group. This allows the relative sensitivities of certain species within a group to be highlighted.

Alternatives Analyzed in Detail

Four principal types of alternatives were identified as a result of scoping:

- In lieu of continued OCS oil and gas leasing, develop alternative energy sources and/or adopt energy conservation programs;

Slow the rate at which future OCS lease sales are held;

- Exclude from leasing consideration some of the areas included in the proposed action;

- Add for leasing consideration more OCS planning areas than are included in the proposed action.

Three principal criteria were used as the bases for determining whether a potential alternative was reasonable for the purpose of analyzing it in detail in the EIS. First, the structure of the alternative had to be related to the issues of size, timing, or location of possible future lease sales. This is consistent with the OCS Lands Act requirement that DOI develop a schedule of potential lease sales that specifies, as precisely as possible, the size, timing, and location of those sales. Second, the alternative could not be redundant with one or more elements of other alternatives that were already being analyzed in the EIS. Finally, it must be consistent with the management principles and other considerations included in Section 18 of the OCS Lands Act. Each of the following alternatives except the No Action alternative reflect consideration of these criteria.

An analysis of the potential effects of not adopting an OCS Oil and Gas Leasing Program for 1997-2002 is required by the regulations that implements NEPA (40 CFR 1502.14(d)). The No Action alternative considers the nature of the environmental impacts that might occur in absence of the potential development attendant to the proposed action (i.e., Alternative 1). The analysis includes the possible environmental impacts of the most likely mix of market-driven substitutes for the energy (including oil imports) that might be produced if the proposed action was implemented. It also considers the impacts of developing other sources of energy (e.g., non-petroleum fuels, solar, nuclear, conservation) that might substitute for some oil and natural gas produced from the OCS. See section II.B for a complete description of the alternative and section IV.D.2 for environmental impacts.