Abstract: Employee #1 was using a small, gasoline-powered sprayer to apply a chemical defoaming agent to the surface at the western edge an aeration lagoon. The foam extended 5 or 6 ft vertically above the surface of the pond and had been blown off the property by the wind. The extreme foaming problem had been treated with a different anti-foaming agent on the previous day. A coworker noticed that the sprayer pump and a utility vehicle used to pull the pump were running unattended alongside the lagoon and that Employee #1 was not in the vicinity. When the coworker investigated the scene, he noticed skid marks on the plastic edge of the lagoon, adjoining the opening to the driver's compartment. He suspected that Employee #1 had fallen in at the location of the skid marks. The coworker could not locate him and summoned help. Divers located his body about two hours later in 18 ft of water; he had drowned. The investigating state police trooper measured evidence of the foam extending 53 in. horizontally from the edge of the plastic liner of the lagoon.