Fact Sheet: High Consequence Areas (HCAs)
- Consequences of pipelines spills can vary greatly, depending on where the release occurs, and the commodity involved in the release.
- Releases from pipelines can adversely affect human health and safety, cause environmental degradation, and damage personal or commercial property.
US Pipeline safety regulations use the concept of “High Consequence Areas” (HCAs), to identify specific areas where a leak could have the most significant consequences. Once identified, operators are required to devote additional focus, efforts, and analysis in HCAs to ensure the integrity of pipelines.
What Criteria Define HCAs for pipelines?
HCAs for natural gas transmission pipelines focuses solely on populated areas.
Identification of HCAs for hazardous liquid pipelines focuses on pipelines that pass close to populated areas, drinking water sources and unusually sensitive ecological resources. Drinking water sources include those supplied by surface water or wells and where a secondary source of water supply is not available. The land area in which spilled hazardous liquid could affect the water supply is also treated as an HCA.
Unusually sensitive ecological areas include locations where critically imperil species can be found, areas where multiple examples of federally listed threatened and endangered species are found, and areas where migratory water birds concentrate.
Good engineering practices and, indeed, pipeline regulations require an operator to take measures to mitigate the consequences of a pipeline failure that could affect a high consequence area and suggest improvements that can include augmenting the leak detection systems that detect leaks in a HCA segment.