EPA RED on 2,4-D:

After a 17-year comprehensive review and thorough health and environmental assessment of 2,4-D under the United States Environmental Protection Agency (EPA) registration program for older pesticides, the agency found that the short and long-term effects of using of 2,4-D were “not of concern” when users followed product label instructions. These findings were part of the Registration Eligibility Decision (RED) for 2,4-D, an evaluative process that all pesticides registered in the U.S. must undergo periodically to ensure that they do not pose health or environmental risks when used as directed.

As of Feb. 2010 all data requirement or data gap studies have been submitted.

More specific information about the RED can be found in the following Backgrounder: