Corrugated Stainless Steel Tubing (CSST) is a thin-walled metallic tubing product that can be used as alternative gas piping material to steel pipe. CSST may have been used in your structure if it was built after 1990, or its gas piping system has been replaced or modified since then.
In 2007, four manufacturers of CSST settled a class action lawsuit in which it was alleged by plaintiffs, but denied by defendants, that CSST posed an unreasonable risk of gas leaks and fire due to lightning strikes.
CSST may have a yellow or black plastic exterior coating and would typically be present inside walls and through and along floor and ceiling joists. It's not the same as the flexible appliance connectors that connect to gas appliances.
CSST must be installed and used only in accordance with applicable codes and manufacturers’ instructions, including those that pertain to bonding and grounding of the piping system. In order to help protect structures from potential lightning strikes, the installer of CSST and/or the owner/operator of the structure where the CSST is used should consider installing an appropriate lightning protection system pursuant to NFPA 780 or other recognized standards.
SoCalGas doesn't provide inspection service for CSST installations. If you're unsure whether CSST was installed in your structure, please contact your builder, contractor or a qualified professional for an evaluation or for more information.