Learn - Step 1: Screening

Screening is the first stage of the EIA process which results in a key EIA decision, namely to either conduct the assessment (based on the likely significant impacts) or not conduct it (in the anticipated absence of such impacts). Screening needs to follow specific procedures often described in the legislation so all the projects follow the same process.

Key contributions of screening to a good EIA:

• Facilitates informed decision making by providing clear, well-structured, factual analysis of the effects and consequences of proposed actions.
• Influences both project selection and policy design by screening out environmentally and/or socially unsound proposals, as well as modifying feasible action.

An essential aspect of conducting an EIA is to determine the level of impact of the proposed project, development or initiative. When we look at major development projects—especially those involving natural resources, such as mining, hydroelectric dams, or oil extraction—we can say for certain that they will require an environmental and social impact assessment. On the other hand, while the development of a tourism project may seem low-risk at first, a second look could reveal that the project requires large amounts of drinking water, energy, the removal of endangered flora or fauna, and will result in extensive sewage production. It may also lead to increased road and air traffic to deliver supplies, visitors and workers. Finally, the impacts of project could change over time. Thus, during the screening step as well as the whole EIA process, impacts are considered over the lifetime of the project, from the construction phase through to operations and after closing.

Most proposals can be screened very quickly because they will have few impacts and will be screened out of the EIA process. Only a limited number of proposals, usually large-scale projects, require a full EIA because they will likely have major irreversible impacts on environmental resources or on people’s health, livelihoods or cultural heritage. However, many projects with medium impacts will require an Environmental Management Plan (EMP) which is a component of a full EIA. EMPs are further described in Step 4: Impact Management.

Most countries in Central America focus on identifying the types of projects, their size and potential impacts to determine the need for an EIA. Overall, we can distinguish two different approaches to screening (United Nations University, UNEP, RMIT, 2007):

• Prescriptive or standardized approaches – Categories for different types of development proposals are outlined in legislation and regulations. Proponents can often decide whether their project will need an EIA based on these standardized approaches. These could include:
  • Legal (or policy) definitions of proposals to which EIA does or does not apply.
  • Inclusion lists of projects (with or without thresholds) for which an EIA is automatically required.
  • Exclusion lists of activities that do not require an EIA because they are insignificant or are exempt by law (e.g., national security or emergency activities).

• Customized approaches – Proposals are screened on an individual or case-by-case base, using indicative guidance with categories.

Different countries and international agencies combine these types of screening procedures. Most often, a simple categorization (such as A – C or 1 – 3) is used. These categories help proponents and licensing agencies decide when a full EIA is needed.

1. For high-impact projects: A full EIA is required because these are likely to have significant serious adverse environmental impacts (i.e., result in irreversible damage, affect vulnerable ethnic minorities, involve involuntary resettlement, or affect cultural heritage sites). These often include:
   • Dams and reservoirs.
   • Forestry and production projects.
   • Industrial plants (large-scale).
   • Irrigation, drainage, and flood control (large-scale).
   • Mining and mineral development (including oil and gas).
   • Port and harbour development.
   • Reclamation, resettlement and new land development.
   • Thermal and hydropower development;
   • Manufacture, transportation, and use of pesticides and other hazardous and/or toxic materials.
2. For medium-impact projects (those likely to have adverse environmental impacts that are less significant than those of in the previous category): Normally a limited EIA will be undertaken to identify suitable mitigation and management measures, and incorporate them into the project. These often include:
   • Agro-industries
   • Electrical transmission; rural electrification
   • Aquaculture, irrigation and drainage (small-scale)
   • Renewable energy
   • Tourism
   • Rural water supply and sanitation
3. For low-impact projects (Those that are likely to have minimal or no adverse environmental impacts): No EIA is required. For example:
   • Construction of small buildings
   • Community garden development
   • Development of wells in a community
   • Outdoor recreation

Development BanksExamples of different types of screening categories within selected Development Banks

Source: IDB, 2011; World Bank , 1999; European Union, 2001.

Central AmericaApproaches to screening in selected countries in Central America

Source: Tiffer-Sotomayor et al., 2015

To determine whether or not the project requires an EIA, project proponents assess their project based upon a set of criteria determined by a designated agency. It is important that screening be done as early as possible in the development of the proposal in order for the proponent and other stakeholders to be aware of possible EIA obligations. It is also important that screening be applied systematically and consistently, so that the same decision would be reached if others did the screening.

The European Union suggests a set of questions to quickly assess project proposals. These questions are designed so that a “Yes” answer will generally point toward the need for EIA and a “No” answer to one not being required (European Commission, 2001).

1. Will there be a large change in environmental conditions?
2. Will new features be out-of-scale with the existing environment?
3. Will the effect be unusual in the area or particularly complex?
4. Will the effect extend over a large area?
5. Will there be any potential for transboundary impact?
6. Will many people be affected?
7. Will many receptors of other types (fauna and flora, businesses, facilities) be affected?
8. Will valuable or scarce features or resources be affected?
9. Is there a risk that environmental standards will be breached?
10. Is there a risk that protected sites, areas, features will be affected?
11. Is there a high probability of the effect occurring?
12. Will the effect continue for a long time?
13. Will the effect be permanent rather than temporary?
14. Will the impact be continuous rather than intermittent?
15. If it is intermittent will it be frequent rather than rare?
16. Will the impact be irreversible?
17. Will it be difficult to avoid, or reduce or repair or compensate for the effect?