U.S. Environmental Protection Agency (EPA) action officials did not complete planned corrective actions under its Libby Action Plan in a timely manner. This occurred because the scope of the work was larger than originally thought; there was no established charter; and there were contracting delays, competing priorities, unanticipated work, and poor communication with stakeholders. Consequently, the Agency has twice revised its estimates for completing actions in response to our December 2006 report. The toxicity assessment is one of two components (an exposure assessment being the other) that makes up the health risk assessment for determining cleanup levels in Libby. In December 2011, EPA informed us that the health risk assessment would be substantially delayed. As a result, the Agency's final determinations that the completed and ongoing cleanup actions are sufficient to address the health risks from site contamination have been delayed from 2 to 6 years, depending on the studies being performed. This is a significant concern, considering that the EPA Administrator declared a public-health emergency at the Libby site in 2009 and the Agency has spent over $400 million on cleanup. Communications about delays in completing Libby Action Plan items, and the reasons for those delays, were not always timely or clearly communicated to stakeholders; and EPA officials failed to update the Agency's follow-up system or notify the Office of Inspector General (OIG) about known delays until planned corrective actions under the Libby Action Plan could not be met.