(a) If the proposed action may or will result in significant impacts to the environment, an EIS is prepared to provide more comprehensive analyses and conclusions about the impacts. Significant impacts of socioeconomic consequence alone do not merit an EIS.

(b) Significance of impacts is determined by examining both the context and intensity of the proposed action (40 CFR 1508.27). The analysis should establish, by resource category, the threshold at which significance is reached. For example, an action that would violate existing pollution standards; cause water, air, noise, soil, or underground pollution; impair visibility for substantial periods; or cause irreparable harm to animal or plant life could be determined significant. Significant beneficial effects also occur and must be addressed, if applicable.

(c) The proponent should use appropriate methods to identify and ascertain the “significance” of impacts. The use of simple analytical tools, which are subject to independent peer review, fully documented, and available to the public, is encouraged.^[4] In particular, where impacts are unknown or are suspected to be of public interest, public involvement should be initiated early in the EA (scoping) process.