Much of the present information on the products formed when seawater is chlorinated is based on observations of laboratory experiments in which chlorine was added to seawater to stimulate conditions of electricity generating plants. Results are reported for a field study at the Port Everglades power plant of the Florida Power and Light Company to investigate reaction products from the chlorination of seawater. Observations indicate that reaction products may be quantitatively as important as the more extensively studied haloforms, with unknown environmental significance.