Which of the following is true of SF6 gas?

SF6 gas, or sulfur hexafluoride, is notable for its properties in electrical insulation and arc suppression. It is indeed true that SF6 can be harmful and has the potential to create toxic substances under certain conditions, particularly when it is exposed to high temperatures or electrical discharges. When this occurs, SF6 can decompose into various toxic fluorides which can pose health risks. Handling SF6 requires caution due to these hazardous properties.

The other options do not accurately describe SF6. For instance, SF6 gas is actually colorless and odorless, which contradicts the notion that it is visible. While it is known for its excellent insulating properties, it does not promote electrical conduction; instead, it operates as an insulator, preventing the flow of current under normal circumstances, which is essential in high-voltage applications. Additionally, SF6 is not used in water systems, as its primary application is within electrical substations and equipment to prevent electrical arcing and enhance performance.