Recent California legislation required the City of Los Angeles to prepare air toxics emissions inventories at its four wastewater treatment plants. This paper presents the results of these inventories, including descriptions of available estimation methods, rationale for method selection, intercomparisons of available methods, and comparisons of emissions by treatment plants. Results of required health risk assessments are also discussed. Observations on the emission inventory process at wastewater treatment plants are offered.zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA Water Environ. Res., 66, 140(1994).