EPA has an updated and expanded third version of its Standardized Analytical Methods for Environmental Restoration following Homeland Security Events report. The report contains methods for laboratories to use in measuring specific contaminants possibly associated with a terrorist attack, evaluating the nature and extent of contamination, and assessing decontamination efficacy. A homeland security emergency could overwhelm laboratories with possibly contaminated samples requiring rapid analysis. Use of the report helps multiple labs to perform consistent analyses and obtain comparable results. EPA developed the report as part of a larger effort to comply with Homeland Security Presidential Directive (HSPD) 8, which establishes policies to strengthen the nation's readiness. EPA formed a workgroup of experts from itself and other agencies. These experts reviewed many analytical methods, seeking to balance the need to use existing techniques and methodologies against the goal of obtaining consistent results. The workgroup selected methods for measuring chemical agents in aqueous/liquid, solid, oily solid, and air matrices, as well as biological agents in water, dust, and aerosol matrices.