As its name implies, caustic soda is caustic and one of many alkaline compounds that are referred to as lye. NaOH, or pure sodium hydroxide, at room temperature is an odorless, white solid.
Caustic soda should be used with caution, as it is an alkaline corrosive that can be hazardous. When it reacts with moisture in the air, it dissolves, generating heat. This heat may cause nearby flammable materials to ignite, resulting in a fire. It should be safely stored in a dry, cool and well-ventilated place, away from oxidizing or organic materials. It should not be allowed to come into contact with metal powders or acids.
Although caustic soda is not a systemic toxin, it is however extremely corrosive and can cause severe burns to body tissues. The eyes are particularly at risk, as caustic soda is able to hydrolyze protein, which is often the cause of severe eye damage.