Since 2004, DHS’s use of its CBRN risk assessments to inform its CBRN response plans has varied, from directly influencing information in the plans to not being used at all. DHS guidance states that response planning and resource decisions should be informed by risk information. GAO’s analysis showed that DHS used its CBRN risk assessments to directly inform 2 of 12 CBRN response plans GAO identified because planners considered the risk assessments to be more accurate than earlier DHS planning assumptions. For another 7 of the 12 plans, DHS officials said that the assessments indirectly informed the plans by providing background information prior to plan development. However, GAO could not independently verify this because DHS officials could not document how the risk assessments influenced the information contained in the plans. GAO’s analysis found general consistency between the risk assessments and the plans. For the remaining 3 plans, DHS officials did not use the risk assessments to inform the plans; for 2 of the 3 plans DHS officials told GAO they were not aware of the assessments. DHS officials also noted that there was no departmental guidance on when or how the CBRN risk assessments should be used when developing such plans.