Typically, the eyelids react to a threat by closing quickly to protect the eyes from harm. However, chemicals can still sometimes reach the eye if the lids don't close quickly enough. Chemicals may be in liquid or powdered form and can cause irritation and burns.
The most dangerous chemicals are strong acids or alkali. Alkali burns tend to be more serious than burns from acid. Alkali chemicals include lye, concrete, mortar, oven and drain cleaners, dishwasher detergent, and fertilizers.