Hazardous waste may be toxic, ignitable, corrosive, reactive, or radioactive. Chromium trioxide is highly toxic, corrosive, and carcinogenic. It is a corrosive and highly toxic gas. Many battery chemicals are corrosive, poisonous or both. It is very poisonous, corrosive, and flammable. Methanesulfonyl chloride is highly toxic by inhalation, corrosive, and acts as a lachrymator. Solutions of HF are colourless, acidic and highly corrosive. The fuel they run off may be flammable, poisonous, corrosive or cryogenic. Molten salts can be highly corrosive and corrosivity increases with temperature. Copper sheathing is waterproof and resistant to ultraviolet light and many corrosive elements. It is displacing the use of fluoroboric acid, which releases corrosive and volatile hydrogen fluoride. This prevents the formation of free hydrogen gas, an essential factor of corrosive chemical processes. It is highly corrosive and an extremely powerful oxidizer. Bulk cargo can be very dense, corrosive, or abrasive. Lithium salts are psychoactive and somewhat corrosive.