Sulfur Hexaflouride Possession of Purchases

Due to its extreme global warming potential, the California Air Resources Board (CARB) passed a regulation restricting Sulfur Hexafluoride (SF6) gas emissions, pursuant to the California Global Warning Solutions Act of 2006. This rule places a ban on the sale, use, and release of SF6 for processes not specifically exempted in Title 17, section 95341 of the California Code of Regulations (17 CCR 95341).

Exemptions to this ban that may apply to UCSF operations include:

  • Use in chemical vapor deposition (CVD) chamber cleaning.
  • Use in etching.
  • Use as a dielectric medium including equipment containing SF6 for use as a dielectric medium.
  • Use as an arc quenching medium in equipment containing SF6 for use as an arc quenching medium.

The above exemptions are not required to keep records for usage or purchases

  • Use during one-time laboratory variable air volume fume hood certifications, pursuant to 8 CCR 5154.1(c)(2)(B).
  • Medical uses, which include the following applications:
  • Injection or other entry of SF6 into a human or other animal body for the purpose of improving health;
  • Use of SF6 in a diagnostic tool in order to either identify a disease or condition by its outward signs and symptoms or analyze the underlying physiological/biological cause(s) of a disease or condition; and
  • Use of SF6 in a medical treatment process for a disease other than a medical condition.
  • Use in equipment calibration and in testing to find alternatives to sulfur hexafluoride use.
  • Use for research in a research facility. Research facilities planning to use SF6 for on or off-site research in a use not covered by 17 CCR 95341(a)(1-9) must:
  • Register with CARB in the form of a letter to the Executive Officer prior to use
  • Monitor and report purchases and usage annually
  • Submit an explanation of research activity
  • Take efforts to minimize sulfur hexafluoride emissions.

Additionally, users and purchasers of SF6 are now required to keep records for 3 years showing the annual quantity of SF6 used and purchased, beginning March 30, 2010This requirement applies to all SF6 purchases, whether your operation is exempted or not. For research users of SF6 records will be collected by EH&S and an annual report issued to CARB by March 30.

If your research / operation currently uses SF6, review the final regulation at or contact UCSF Environmental Programs immediately to determine if you qualify for an exemption.

Gas Insulated Switchgear Containing Sulfure Hexafluoride

“Gas-insulated switchgear or GIS” means all electrical power equipment insulated with SF6 gas regardless of location. Gas insulated switchgear or GIS includes switches, stand-alone gas-insulated equipment, and any combination of electrical disconnects, fuses, electrical transmission lines, transformers and/or circuit breakers used to isolate gas insulated electrical equipment.

If you have a GIS, you are subject to the Regulation for Reducing Sulfur Hexafluoride Emissions from Gas Insulated Switchgear sections 95350 to 95359, title 17, California Code of Regulations.

For each calendar year specified below, the maximum annual SF6 emission rate for each GIS owner’s active GIS equipment shall not exceed the following:

Calendar Year

Maximum Allowable SF6 Emission rate










2020, and each calendar year thereafter












Annual reporting requirements due June 1 to the CA Air Resources Board for non-hermetically sealed insulated switchgear as follows:

  • Weight of gas containers on hand ending December 31 of the previous year
  • Records of SF6 gas and equipment acquisitions and disbursements
  • Records for the addition or removal of SF6 from any piece of equipment

If you have a GIS, see the current regulation here: and contact UCSF Environmental Programs to register your equipment.

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