Fugitive air emission data have been collected for treatment, storage, and disposal operations to support a Regulatory Impact Analysis (RIA) for Hazardous Waste Disposal Facilities. Five sampling approaches have been used for measuring air emission rates from these operations. They are: (1) emission isolation flux chamber, (2) vent sampling, (3) concentration-profile technique, (4) transect technique, and (5) mass balance. Each of these techniques are compared as to their precision, potential applications, and specific limitations of the approaches. Data are presented from sites at which the approaches were applied. Results are compared and contrasted where different techniques are compared as to their precision, potential applications, and specific limitations of the approaches. Data are presented from sites at which the approaches were applied. Results are compared and contrasted where different techniques were used to measure emission rates at the same operation. Finally, recommendations are made for selection of an appropriate sampling approach based on the field experience gained.