The purpose of this interim guidance is to provide information and insight to assist public policy and health system leaders in preparing for and responding to an MCE caused by terrorist use of explosives (TUE). This document provides practical information to promote comprehensive mass casualty care in the event of a TUE event and focuses on two areas: 1. leadership in preparing for and responding to a TUE event, and 2. effective care of patients in the prehospital and hospital environments during a TUE event.