1.1 ,The framework discussed in this guide is limited to facilities with underground storage tanks (USTs) storing hazardous substances or petroleum at ambient temperature and atmospheric pressure. This guide is not intended to provide detailed technical specifications for implementation of the approaches described in this document, nor to be used as an enforcement tool, but rather to identify the important information used for environmental management of underground tank systems. The term “,must”, is used where United States federal requirements apply. References to ASTM standards and other industry guidelines have been provided to address implementation of the approaches discussed in this guide. Many states and some local agencies have adopted UST rules that place additional responsibilities on the owners/operators of UST systems. Refer to state and local regulations that may contain additional requirements. It is not possible to identify all considerations or combinations of conditions pertinent to a unique underground storage tank system.