Biological disasters in the United States

How common are Biological disasters in the U.S.?

FEMA has issued 14 federal disaster declarations classified as biological between 2020 and 2021, affecting 14 states and territories. Each declaration represents a formal federal recognition that an event exceeded state and local response capacity — unlocking Public Assistance, Individual Assistance, or Hazard Mitigation Grant Program funding depending on the declaration class (DR, EM, or FM). Raw declaration counts therefore measure the federal response footprint, which is a lagging and thresholded indicator: smaller events handled entirely at the state level never appear, and declaration thresholds have been recalibrated over the dataset's multi-decade history.

Geographic concentration varies widely by disaster type, and biological follows this pattern. The three states with the most biological declarations on record are AL (1 declarations), AZ (1 declarations), AS (1 declarations). Together they account for a large share of all federal biological responses — a reflection of underlying hazard climatology, population density in exposed areas, and historical development patterns in vulnerable zones. States with the fewest declarations, including WA (1), CA (1), NY (1), generally face less exposure to this hazard type, though physiographic coverage varies — some low-count states still see significant local events that never crossed a federal threshold.

Temporal patterns in the record tell a separate story. The peak year on record was 2020, with 12 biological declarations issued that single year — a clustering driven by major multi-state events and the federal government's declaration cadence. The most recent year on record is 2021, with 2 declarations. Trends over the 1+ year history reflect a mix of physical climate drivers (multi-decadal hazard cycles, warming-related shifts in frequency or severity), changes in federal declaration policy, and growing community exposure as development expanded into higher-risk areas. For planning and preparedness purposes, combine this federal declaration history with local hazard maps, FEMA National Risk Index county scores, and insurance-industry loss data — which together give a more complete picture than declarations alone.