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Multiple chemical sensitivity (MCS) is a chronic medical condition characterized by symptoms that the affected person attributes to low-level chemical exposure. Commonly accused substances include smoke, pesticides, plastics, synthetic fabrics, scented products, petroleum products, and paint fumes. Symptoms are often vague and non-specific, such as nausea, fatigue, dizziness and headaches, but also commonly include inflammation of skin, joints, gastrointestinal tract and airways.

More details are available in the Wikipedia Multiple chemical sensitivity article.