This document revises and expands upon the document issued on January 2009 ("Background Document and Progress Report for Essential Requirements of Mandatory Reporting for the Western Climate Initiative, Third Draft") that addressed continuing work conducted by the WCI Partners and its Reporting Committee. Its purposes are to:

1. Respond to stakeholder comments received on the January 2009 document;
2. Present proposed revisions of Essential Requirements sections previously released;
3. Present proposed new Essential Requirements sections, including rule-format language for some source category requirements that were previously presented in a narrative discussion format; and
4. Seek public comment on revised and new reporting Essential Requirements.