|EPA 1994 Toxics Release Inventory
Public Data Release, Box 3-1
Some reported increases and decreases are real_that is, they reflect changes in the amounts of TRI chemicals actually released or transferred. Other reported increases and decreases are accounting or "paper" changes that do not reflect any actual change in releases and transfers. Some examples follow.
Source reduction activities, such as process changes, elimination of spills and leaks, inventory control, improved maintenance, chemical substitution, and alternative methods of cleaning and degreasing can cause real reductions in TRI releases and transfers.
Installation of pollution control equipment may lead to real reductions in TRI releases/transfers. However, if the pollution control does not destroy the reported chemical, it may merely shift waste from one type of release or disposal to another.
Increased recycling and reuse of waste or sale of waste as raw materials or products will result in real decreases in TRI releases and/or transfers for treatment and disposal.
Production changes can cause real changes in the quantities of TRI chemicals released or transferred by facilities. Releases/transfers are likely to increase when production increases and decrease when production decreases, although the relationship is not necessarily linear.
One-time events unrelated to normal production processes, such as accidental releases or clean-up operations, can cause a real but anomalous increase in the reporting year in which they occur and then a decrease from that abnormally high level the following year.
Changes in estimation or calculation techniques can cause a change in the amount reported without a corresponding change in actual releases or transfers.
Clarifications of reporting instructions or changes in the way a facility interprets those instructions may cause a change in reported amounts without an actual change in releases or transfers. For example, revised guidance concerning the de minimis exemption and beneficiation activities which was issued by EPA for 1991 may have resulted in lower reported releases for some facilities.
Similarly, a facility's reported releases may go down without an actual reduction in releases if the facility begins to take advantage of a reporting exemption or optional reporting method for the first time. One large source of this type of paper change is the optional reporting method for ammonium sulfate (solution), which is discussed in detail in Box 1-3.
Apparent increases or decreases can occur if a facility makes a reporting error one year and does not submit a revision for that year, but does not repeat the error the following year.
Source: USEPA 1994 Toxics Release Inventory Public Data Release (EPA 745-R-96-002, June 1996).
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