The pronounced affinity of arsenic for keratinizing structures makes the skin a critical organ in arsenic toxicity. Systemic toxicity of arsenic is sometimes manifested in a variety of symptoms including keratosis, hyperpigmentation, skin eruptions, dermal lesions, Bowen's disease, various forms of skin cancer, and neoplasia. Chronic dermal accumulation of arsenic increases the susceptibility of the skin to ultraviolet radiation. It is generally presumed that ingestion of drinking water is the primary exposure route for arsenic, but no clear pathway has been established for the transport of arsenic from the GI tract to the skin. Arsenic in water, soil and dust come into contact with human skin during daily activities, work or play and has the potential to be absorbed from the water and soil matrices. Absorption of arsenic through the skin has generally been ignored in previous studies on the human exposure to arsenic in the environment.