This recommended practice provides guidance on the design and operation of solution-mined underground hydrocarbon liquid or liquefied petroleum gas storage facilities. It is intended for cavern engineers, supervisors, and all persons involved in liquid cavern operations. This recommended practice is based on the accumulated knowledge and experience of geologists, engineers, and other personnel in the petroleum industry. All aspects of solution-mined liquid hydrocarbon underground storage design and operation are covered, including site selection, cavern development, cavern hydraulics, brine facilities, wellhead and hanging strings, cavern testing, and cavern abandonment. A section on risk management is included. This recommended practice does not apply to caverns used for natural gas storage, waste disposal purposes, caverns that are mechanically mined, depleted petroleum reserve cavities, or other underground storage systems that are not solution-mined. This document supersedes API RP 1114.