There are three main types of pipelines in Contra Costa County, and it is important to understand what the different types are since they have different safety considerations and are regulated by different agencies under different rules.
The three main types are:
Hazardous Liquid Lines: These are the lines that move crude oil to the local refineries and then move refined products (gasoline, jet fuel, diesel, etc.) from the refineries to other markets.
Natural Gas Transmission Lines: These are the relatively larger, higher-pressure pipelines that move gas from production or storage to where the gas is distributed to our homes and businesses. They operate at pressures in the range of 300 to over 1500 pounds per square inch. In Contra Costa County, all natural gas transmission lines are operated by PG&E.
Natural Gas Distribution Lines: A distribution line is a relative small, lower pressure pipeline used to supply natural gas directly to our homes and businesses. Gas distribution pipelines comprise by far the most mileage of pipes; they carry odorized gas (with the characteristic smell of rotten eggs) throughout urban areas. In Contra Costa County, all natural gas distribution lines are operated by PG&E.
Pipelines are also identified as either interstate pipelines or intrastate pipelines. Interstate pipelines are typically , but not always, longer transmission pipelines that cross state lines; intrastate pipelines are transmission pipelines that lie wholly within a single state.
There are over 4,000 miles of natural gas pipelines in Contra Costa County, fewer than 300 miles of which are transmission lines, and the rest are distribution lines and services. All the natural gas distribution pipelines are operated by Pacific Gas & Electric under the jurisdiction of the California Public Utilities Commission.
Hazardous liquid (HL) transmission pipelines in Contra Costa County total close to 500 miles. Roughly two-thirds of the HL pipelines carry refined products, and about one-third carry crude oil. Pipelines that are within refinery facilities are regulated separately from transmission and distribution lines and are not examined in this project.