The water-based foam continues to kill insects returning to the nest for thorough extermination. Safe for use on most ornamental plants and shrubs, it won’t stain most home siding or asphalt shingles, depending on their condition and cleanliness. The formula contains 0.5% Permethrin, a powerful insecticide. For areas with electrical equipment, use Bengal Non-Conductive Wasp & Hornet Killer.