A more thorough explanation:

An environmental impact report is a study that looks at how a construction project or development would affect the environment in the area. This report considers factors like population, traffic, schools, fire protection, endangered species, archeological artifacts, and community beauty.

For example, if a company wants to build a new factory in a town, they would need to submit an environmental impact report to the local government. The report would look at how the factory would affect the air and water quality in the area, how much traffic it would generate, and if it would harm any endangered species or archeological artifacts in the area.

Many states require these reports to be submitted before a project can be approved. If the government finds that there will be no negative impact on the environment, they may issue a "negative declaration" and approve the project.