Source: RTK Net
"Form A" is a TRI reporting form on which a facility can notify EPA that it meets the TRI criteria for reporting, but that it has releases and waste less than a certain threshold. Form A was added to TRI for the 1995 reporting year. From then through the 2005 reporting year, a Form A could be filed if the facility had 500 pounds or less of production-related waste. Since most releases (other than those from accidents or cleanups) involve generation of production-related waste that is later released, this put an effective limit for most facilities of 500 pounds of releases as well. When PBTs were started to be treated specially in TRI in 2000, PBTs were disallowed from Form A reporting.
Starting with the 2006 reporting year, EPA changed Form A so that from then on, a non-PBT chemical could be reported under Form A if it had 2000 pounds or less of releases and 5000 pounds or less of all waste. A PBT chemical could be reported under Form A if it had zero releases and 500 pounds of less of all waste.
RTK NET has decided that listing Form A submissions as if they have zero releases and waste is misrepresenting the data. If a facility meets the TRI reporting criteria but does actually have zero releases and waste, they can file a Form R reporting this, and many facilities do. Form A doesn't indicate zero, it indicates some undetermined number between zero and the Form A release or waste threshold.
There is a longstanding method of representing this situation that has been used within TRI since its inception to represent release and transfer range reporting. If the release or transfer is reported as a range, 1-10 pounds for instance, then the TRI database shows this as the midpoint of the range -- 5 pounds in this example. RTK NET has done the same thing for Form A reporting, using zero as the lower limit of the range and the Form A reporting threshold as the upper limit of the range, and taking the midpoint between them.