(a) No agency involved in an action may undertake, fund or approve the action until it has complied with the provisions of SEQR. A project sponsor may not commence any physical alteration related to an action until the provisions of SEQR have been complied with. The only exception to this is provided under section 617.5(c) (24), (27), and (34) of this Part. An involved agency may not issue its findings and decision on an action if it knows any other involved agency has determined that the action