Hydroquinone is a white crystalline solid that is soluble in water. (see reference 2) Hydroquinone is a chemical used in a variety of de-coloring applications (reference 1).
Hydroquinone is used as a developing agent in photography. (reference 2)
Hydroquinone is used as an antioxidant in rubber and food.
Chronic exposure to hydroquinone may produce a variety of health concerns. These include nausea, vomiting, eye injuries such as conjunctivitis. (reference 2). Injestion of a large amount of hydroquinone may result in Tinnitus (ringing in the ears), dizziness, headache, nausea, vomiting, dyspnea, erosion of the gastric mucosa, edema of internal organs, cyanosis, convulsions, delirium, and collaps (ref 2)