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Part 3 - Determination of Significance (SEAF)

Short Environmental Assessment Form (SEAF)

The Lead Agency is responsible for the completion of Part 3.

For every question in Part 2 that was answered "moderate to large impact may occur", or if there is a need to explain why a particular element of the proposed action may or will not result in a significant adverse environmental impact, please complete Part 3. Part 3 should, in sufficient detail, identify the impact, including any measures or design elements that have been included by the project sponsor to avoid or reduce impacts. Part 3 should also explain how the lead agency determined that the impact may or will not be significant. Each potential impact should be assessed considering its setting, probability of occurring, duration, irreversibility, geographic scope, and magnitude. Also consider the potential for short-term, long-term, and cumulative impacts.


The purpose of Part 3 is to summarize evaluations made during Part 2 and then decide if the moderate to large impacts identified in Part 2 may be significant. Part 3 is where the reviewing agency discusses for each potential impact, the context, probability of occurrence, duration of impact, irreversibility of impact, geographic scope, magnitude, and cumulative impacts. Note that some of these features - such as context, duration, irreversibility, and magnitude - were also considered in Part 2 as part of decision-making about whether an impact was small, moderate or large. The Part 3 evaluation looks again at those features to determine if a potential impact is significant or not.

Part 3 is important because it will help the reviewing agency determine if impacts are significant, if they have been mitigated by some aspect of the project, or if additional evaluation needs to be done through an environmental impact statement. Part 3 expands on the decisions made in Part 2. Taken together, Parts 1, 2, and 3 will create a strong record of the 'hard look' required by SEQR.

Note that nothing in this workbook, particularly the guidance offered in Part 2 and 3, is found in regulation. While the EAF's need to be completed according to the Part 617 regulations, interpretation on the size or significance of an impact is at the discretion of the reviewing agency.

Instructions for the Reviewing Agency

Part 3 should include the following:

  • Identification of the impact
  • Assessment of each impact considering the project's setting, probability of occurring, duration, irreversibility, geographic scope and magnitude, and the potential for short-term, long-term and cumulative impacts
  • Identification of any measures or design elements that have been included as part of the project to avoid or minimize impacts
  • Explanation of how the reviewing agency has determined that the impact may or will not be significant, and
  • A final determination of whether the project may or will not result in one or more potentially large or significant adverse impacts.

General Instructions

  • It is the responsibility of the reviewing agency to complete Part 3 and determine the significance of any of the identified impacts. Part 3 evaluates only those impacts identified in the Part 2 table as being moderate to large.
  • You should use information submitted by the applicant or project sponsor in Part 1 and your evaluation of that information in Part 2 to complete Part 3.
  • You can request clarification or expansion of information submitted in Part 1 if needed to complete Part 3. However, new information that is requested should come from currently existing, or readily available sources. It is not intended that exhaustive new studies be developed to complete Part 3.
  • Although it is not a requirement to do so, Part 3 can also be used to explain why a particular impact was deemed to be small, why it may not be significant, or if it has already been mitigated.
If you checked "No or small impact may occur" for ALL eleven questions in Part 2

Go to the signature box on page four and check the second box indicating that you have determined that the proposed action will not result in any significant adverse environmental impacts. This will serve as your negative declaration. Be sure to sign it.

You are only required to check the second box at the bottom of Part 3 on page four, fill out the lead agency information, date, and sign the form. You are not required to complete Part 3, but you may use Part 3 to explain any measures or design elements that have been included by the project sponsor to avoid or reduce impacts, or to explain your rationale for determining that the impact will not occur or will be small.

If you checked "Moderate to large impact may occur" for ANY question in Part 2

Then each of these questions will need additional evaluation in Part 3. Part 3 will help the reviewing agency decide if the impacts identified are significant and whether or not to require an environmental impact statement.

Determining Significance of an Impact

If you have identified any potential moderate to large impacts in Part 2, you can move on to the next section of the workbook which explains how to determine their significance.

More about Part 3 - Determination of Significance (SEAF):

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