Inhalation of sodium hydroxide dust, mist, or aerosol may cause irritation of the mucous membranes of the nose, throat, and respiratory tract. Sodium hydroxide is odorless; thus, odor provides no warning of hazardous concentrations. Mucous
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membrane irritation occurs at the OSHA PEL (2 mg/m ) and isgenerally an adequate warning property for acute exposure to sodium hydroxide. However, workers exposed to prolonged or recurrent mists or aerosols of sodium hydroxide can become somewhat tolerant of the irritant effects. Sodium hydroxide of sufficient strength can hydrolyze proteins in tissues and can kill cells in tissues