L is not detoxified by the body. Common routes of entry into the body are ocular, percutaneous, and inhalation. Lewisite is generally considered a suspect carcinogen because of its arsenic content. L irritates eyes and skin and gives warning of its presence. Instant pain, conjunctivitis and blepharospasm leading to closure of eyelids, followed by corneal scarring and iritis.
Mild exposure produces reversible eye damage if decontaminated instantly.
More permanent injury or blindness is possible within one minute of exposure. Immediate stinging pain increasing in severity with time. Blisters appear within 12 hours after exposure with more pain that diminishes after 2-3 days. Tender skin, mucous membrane, and perspiration-covered skin are more sensitive to the effects of L. This, however, is counteracted by L's hydrolysis by moisture, producing less vesicant and higher vapor pressure product. Irritating to nasal passages and produces a burning sensation followed by profuse nasal secretions and violent sneezing.