TOXMAP facility locations are calculated by an estimation process that relies on "geocoding." Geocoding is a method that assigns a latitude and a longitude to an address. Even the most accurate latitude/longitude coordinate calculations, including those used by TOXMAP, are estimates; this can account for minor inaccuracies in site locations on a map.

Addresses are geocoded using software that accesses location information from a variety of sources which contain street segments; address ranges are attached to each side of the segment. TOXMAP's geocoding program estimates the location of each facility address based on this address range. Although very accurate, these locations are estimates, and they should not be used to definitively locate a particular facility.

More information about the accuracy of locations in TOXMAP can be found in the TOXMAP FAQ "How accurate are TRI locations in TOXMAP?"