; and (ii) provide timely information to assist the lead agency in carrying out the requirements of this subsection. (3) Treatment as involved Federal agencies A Federal agency with responsibility to issue an authorization or take an action for or related to a proposed agency action shall work with the lead agency to ensure that the agency issuing the authorization or taking the action is treated as an involved Federal agency for the action. (4) Exceptions The lead agency may waive the requirements of paragraph (1) with respect to a proposed agency action if— (A) the project sponsor requests that agencies issue separate environmental documents; or (B) the obligations of a cooperating agency or other involved Federal agency under this title have already been satisfied with respect to the proposed agency action. (c) Scope of review In developing an environmental document for a proposed agency action, the lead agency and any other involved Federal agencies shall only consider the effects of the proposed agency action that— (1) occur on Federal land; or (2) are subject to Federal control and responsibility. (d) Project sponsor preparation (1) In general A lead agency shall allow a project sponsor to prepare an environmental document for a proposed agency action on request of the project sponsor. (2) Guidance A lead agency may provide a project sponsor that elects to prepare an environmental document under paragraph (1) with appropriate guidance and assistance in the preparation of that environmental document. (3) Independent verification A lead agency shall— (A) independently evaluate the environmental document prepared by a project sponsor under paragraph (1)