Always add acid to water. Never add water to acid. Never store corrosives above eye level. It is a good practice to store corrosives in a tray or bucket to contain any leakage. Use and Storage of Hydrofluoric Acid Hydrofluoric acid is extremely hazardous and deserves special mention.
Hydrofluoric acid can cause severe burns and inhalation of anhydrous hydrogen fluoride can be fatal.
Initial skin contact with hydrofluoric acid may not produce any symptoms, so it may give a person the feeling that it is not hazardous, when indeed it is. Only persons fully trained in the hazards of hydrofluoric acid should use it. Always use hydrofluoric acid in a properly functioning fumehood. Be sure to wear your personal protective clothing. If you even suspect that you have come in direct contact with hydrofluoric acid wash the area with water for at least 15 minutes, remove clothing, and then seek prompt medical attention.