This report presents a Level I materials balance study on 2-chlorophenol, 4-chlorophenol, 2,4-dichlorophenol, 2,4,5-trichlorophenol, 2,3,4,6-tetrachlorophenol and pentachlorophenol. Areas of major interest were production quantities, producers, consumption amounts and emissions to air, land, and water related to the above sources. The estimated production quantities in 1976 of the compounds studied were as follows: 2-chlorophenol, 9000 kkg; 4-chlorophenol, 9800 kkg; 2,4-dichlorophenol, 39,000 kkg; 2,4,5-trichlorophenol, 6300 kkg; 2,3,4,6-tetrachlorophenol, 1,800 kkg; and pentachlorophenol, 22,000 kkg. Waterborne emission was considered to be the main pathway of chlorophenols release to the environment because of the physical characteristics of these chemicals. The estimated quantities of aquatic emissions associated with the chlorophenols studied were as follows: 2-chlorophenol, 430 kkg; 4-chlorophenol, 650 kkg; 2,4-dichlorophenol, 870 kkg; 2,4,5-trichlorophenol, 105 kkg; 2,3,4,6-tetrachlorophenol, 67 - 160 kkg; pentachlorophenol, 840 - 1400 kkg. Throughout this report, estimations and assumptions were made in places where needed information was not available. Bases for these estimations were stated and defined. Recommendations for further studies were also made.