Benzyl chloride is used as a chemical intermediate in the manufacture of certain dyes and pharmaceutical products and as a photographic developer. The acute (short-term) effects of benzyl chloride from inhalation exposure in humans consist of severe irritation of the upper respiratory tract, skin, eyes, and mucous membranes, and lung damage along with pulmonary edema (fluid in lungs). Exposure to high concentrations also causes effects on the central nervous system (CNS). Animal data indicate that long- term exposure to benzyl chloride by gavage (placing it experimentally in the stomachs of mice) increased the incidence of benign and malignant tumors at multiple sites and resulted in a significant increase in thyroid tumors in female rats. EPA has classified benzyl chloride as a Group B2, probable human carcinogen.