Pilot laboratory experiments were conducted to assess preliminarily the possibility of effects on biota from exposures of various durations to electric fields of 10 and 20 volts per meter and magnetic fields of 1.0 and 2.0 gauss at two extremely low frequencies, 45 and 75 Hz. In some experiments the electric field was set up in a conductive medium (moist soil, water, or nutritive medium) and in others in the air. In one study, 0.5 mA current at these frequencies was passed through the bodies of dogs concurrent with the application of the fields. The laboratory studies consisted of the following with possible electromagnetic effects indicated, if any: Rat Fertility Studies - no effects; Rat Avoidance Learning Study - no effects; Canine Physiology Study - possible elevated blood pressure and rectal temperature; Insect Mutagenic Study - possible dominant lethal mutation rate increase; Bacteria Mutagenesis Study - no effects; Plant Cytogenetic Study - no effects; Seed Germination and Early Growth Study - possible growth inhibition in one of three species; Multiple-Species Electric Field Preception and Preference Study - no preference effects except in a few turtles which reacted to the onset of 20 v/m fields. Fish 'preceived' the onset of 10 v/m fields.