Tier I forms provide for listing the general location for all applicable chemicals in each hazard category, including the names and identifications of buildings, tank fields, lots, sheds, or other such areas.

Tier II forms provide for reporting buildings, at a minimum, and allow facilities to describe briefly the location of hazardous chemicals on the form itself or to submit site plans or site coordinates.  Submitting additional information, such as site plans and site coordinate system may be useful on a site-by-site basis but is not necessary for every facility.