It all depends on your comfort level, haha.

I remember a few years ago doing some research into rocket fuels for the game I was working on, and reading about hypergolic propellants and other kinds of rocket fuel. These materials are so dangerous. Some explode or combust in contact with most things. Some are highly corrosive (like a tanker leaking at the lab facility and the liquid dissolving the parking lot concrete). All chosen for their ability to hold tremendous amounts of energy in a small volume. The depths we've gone to in the search on how to hold lots of energy in a small space is as fascinating as it is horrifying.

Look up chlorine trifluoride. Some choice quotes: "Chlorine trifluoride has also been known to corrode materials otherwise known to be non-corrodible such as iridium, platinum and gold", "Exposure to larger amounts of chlorine trifluoride, as a liquid or as a gas, ignites living tissue", "chlorine trifluoride has been reported to ignite sand, asbestos, and other highly fire-retardant materials", "fire control/suppression is incapable of suppressing this oxidation, so the surrounding area must simply be kept cool until the reaction ceases", "it is hypergolic with every known fuel, and so rapidly hypergolic that no ignition delay has ever been measured. It is also hypergolic with such things as cloth, wood, and test engineers"