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INTRODUCTION Cement kiln dust (CKD) is a waste product that accumulates ac the rate of 4 to 12 million tons per year in the United Slates (2, 4)3. This duet has considerable resource potential: It is already being used as a neutralizer for coal mine waste effluents, and the agri- cultural and construction industries are beginning to use it more extensively as a substitute for lime. In the proposed hazardous waste guidelines of 1978 (4) promulgated under the Resource Conserva- tion and Recovery Act (RCRA) of 1976 (I1), the Environmental Protection Agency (EPA) placed CKD in a "Special Wastes" category pending more informa- tion on Che composition, characterist- ics, and degree of hazard posed by this waste. In 1980 the "Special Wastes" category was removed (5), but a 3-year EPA study of the hazard potential of CKD was approved by Congress (10). Part of the concern over the environmental effects of waste CKD resulted from a single study of the heavy metals content of a CKD sample from BLaubeuren, West Germany, showing lead and zinc contents of 5,620 and 16,200 ug/g, respec- tively (3). The only other analysis of CKD for heavy metals used in the EPA study was sample from Polk County, Ga., showing 124 ug/g for lead and 145 ug/g for zinc (12). A contracted EPA study of the received in 1-gallon cans and prepared cement industry con- cluded that: Waste kiln dust is probably the most serious pollution control problem facing the cement industry at this time. Relatively little is known about the dust, so environmentally adequate management techniques are difficult to specify (2). An exploratory evaluation of the environmental effects and of Che re- source recovery potential of the ele- ments present in CKD was initiated at Che Bureau of Mines Avondale (Md.) Re- search Center shortly after publication of the 1978 EPA guidelines. Results of the First phase of this research (8), discussed major, minor, and trace ele- ment concentrations, mineralogy, anion composition, chemically bound water, C02, and EP toxicity leach test re- sults. The present report gives char- acterization data for the U.S. cement industry nationwide. Information on noncarbonate carbon has been added For all samples, as have mercury determina- tions on selected samples, and signifi- cant interelement correlation coeffici- ents Eor the major, minor, and trace elements. SAMPLES Samples of CKD were requested from operating plants located in the contigu- ous United States and Hawaii; 113 samples from 102 plants, representing about 70 percent of the total U.S. cement industry, were received and ana- lyzed. The remaining plants either did not respond to the inquiry or had no disposal problems because all their waste dual was recycled. Table 1 lists the States and the number of samples received from each State. Samples were received in 1-gallon cans and prepared for analysis by the Following proce- dure: 1. The sample as received vas blended in a twin-shell blender for 30 minutes, then riffle-split into two portions. 2. One half of the sample was labeled and stored, and the other half was passed through a 100-mesh sieve. Any portion of the sample coarser than minus 100 mesh was ground in a Wiley mi114 to pass 100 mesh. 3Underlined numbers in parentheses refer [o items in the list of references at [he end of this report. Reference to specific brand names is made for identification only and does not imply endorsement by the Bureau of Mines.