Dead animals/birds/fish

Not just an occasional incident, but numerous animals (wild and domestic, small and large), birds, and fish in the same area

Lack of insect life

Normal insect activity (ground, air, and/or water) missing, dead insects evident in the ground/water surface/shoreline

Physical symptoms

Numerous individuals experiencing unexplained water-like blisters, wheals (similar to bee stings), pinpointed pupils, choking, respiratory ailments and/or rashes

Mass casualties

Numerous individuals exhibiting unexplained serious health problems ranging from nausea to disorientation to difficulty in breathing to convulsions and death

Definite pattern of casualties

Casualties distributed in a pattern that may be associated with possible agent dissemination methods

Illness associated with confined geographic area

Lower incidence of symptoms for people working indoors than outdoors, or the reverse

Unusual liquid droplets

Numerous surfaces exhibiting oily droplets/film; numerous water surfaces displaying an oily film (no recent rain)

Areas that look different in appearance

Not just a patch of dead weeds, but trees, shrubs, bushes, food crops, and/or lawns that are dead, discolored, or withered (no current drought)

Unexplained odors

Smells ranging from fruity to flowery to sharp/pungent to garlic/horseradish-like to bitter almonds/peach kernels to newly mown hay; the particular odor is completely out of character with its surroundings

Low-lying clouds

Low-lying cloud/fog-like condition that is not explained by its surroundings

Unusual metal debris

Unexplained bomb/munitions-like material, especially if it contains a liquid (no recent rain)