Welcome. This site is administered by the Pipeline and Hazardous Materials Safety Administration (PHMSA), and provides information concerning regulations on Pipeline Integrity Management in High Consequence Areas for Hazardous Liquid Operators (49 CFR Part 195.450 and .452). The "Liquid IM Rule," as it is commonly referred to, became effective through two related rulemakings (May 29, 2001 and February 15, 2002), and represented a significant enhancement to PHMSA's existing pipeline safety regulations.

Briefly put, the Liquid IM Rule specifies how pipeline operators must identify, prioritize, assess, evaluate, repair and validate—through comprehensive analyses—the integrity of hazardous liquid pipelines that, in the event of a leak or failure, could affect High Consequence Areas (HCAs) within the United States. These HCAs include:

• population areas
• drinking water and ecological resources that are unusually sensitive to environmental damage
• commercially navigable waterways.

For an overview of the progress being made under the Liquid IM Rule, please see our Performance Measures page. There you will also find a link to the tabulated annual submissions provided by pipeline operators in accordance with this rule.

Other links on the left provide a great deal of additional information as well, including an operator IM process flowchart and a fact sheet that summarizes key requirements of the Liquid IM Rule; details of the Liquid IM Rule itself; a glossary of related terminology; FAQs; and other information useful in more fully understanding the Liquid IM Rule. This site is highly inter-linked in order to assist users in locating information on a particular subject.

Continuing implementation of the Liquid IM Rule sometimes results in rule revisions, new interpretations, or expanded clarifications. This site is updated as necessary to reflect these developments