An Aggregate Production Operation (APO) refers to any site where aggregates are being (or have been) removed or extracted from the earth, including the entire area of extraction, stripped areas, haulage ramps, and the land on which plant processing for the raw materials is located. Rock quarries, gravel pits, borrow pits, and other commercial APOs are required to register with TCEQ and undergo recurring inspections. APOs are included with their location, material type, permit number, and other information.