Chemical and Material Risk Management Program

Sulfur Hexafluoride (SF6)

What is sulfur hexafluoride?

• Sulfur hexafluoride is a non-toxic, colorless gas that traps solar radiation, warming the atmosphere. It is manufactured for use in electrical transmission equipment and electronic components among other industrial and military applications.

What are common uses of sulfur hexafluoride?

• SF6 is commonly used in various electronic components and in the production of the metals magnesium and aluminum. Its primary use is in electrical transmission equipment and in electric power facilities owned and operated by the private sector. DoD operates some power facilities on military bases.
• SF6 is used in specialized applications in key weapons systems and platforms where there are no known substitutes.

Why is SF6 on the Emerging Chemicals Action List?

• The primary environmental concern with SF6 is its potential to contribute to global warming. It warms the atmosphere at 23,900 times the impact of carbon dioxide (CO2) and is estimated to persist for 3,200 years.
• SF6 has a number of DoD applications in electric power plant operations; command, control, and communications equipment; and weapons systems. Efforts to explore substitutes have begun but there are no known, equally effective substitutes at this time.
• Possible regulation of SF6 may affect its availability and cost in the marketplace. Therefore DoD’s ability to train personnel to use key equipment and weapons systems may be adversely affected.
• SF6 is a non-toxic, odorless gas with few, if any, potential health effects. It is extremely unlikely that the general public or workers would be exposed to concentrations of sulfur hexafluoride resulting in any health effects. The U.S. Environmental Protection Agency (EPA) has not assigned health risk values to sulfur hexafluoride but does provide information on its global warming potential.

How is the military managing risks posed by SF6?

• The DoD is currently refining its information on where, how, and how much SF6 is used. New procedures have been implemented for loading and tracking the gas that have reduced use of the chemical by 52,000 pounds a year — the equivalent of retiring 572,000 tons of carbon dioxide annually.
• The DoD is currently reviewing its current and planned uses of SF6 to determine where emissions can be recaptured and reused.
• While some military applications have no current substitutes for sulfur hexafluoride, it appears alternative gases could be used in some equipment. A Small Business Innovation Research grant has been awarded to develop techniques for reducing or replacing reliance on the chemical.