ASSESSMENT AND CHANGES IN REPORTED TRI RELEASES AND TRANSFERS BETWEEN1989 AND 1990

This study presents results of the first statistically designed study to determine reasons for reported Toxic Release Inventory (TRI) releas es and transfers changing from year to year. Data for the study were c ollected through telephone interviews with a stratified random sample of 1,206 facilities. Each facility was asked to explain the extent to which three factors - source reduction, production fluctuation, and me asurement change - contributed to reported changes in TRI releases and transfers between 1989 and 1990. Participants responses were weighted and estimates of the reasons for change were calculated for industry and national levels. The results show that source reduction had the gr eatest impact on net quantity change - at least 45 percent of the tota l net reductions. However, all three variables contributed to both inc reases and decreases in releases and transfers. Therefore, comparing t he aggregated results of each variable can be difficult since the true eff ect of each variable may be masked by quantity increases and decr eases which have canceled each other out.