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CAS No. 123-31-9

Hydroquinone (C₆H₄(OH)₂) is a light-tan, light-gray, or colorless crystal. Exposure to hydroquinone may cause irritation to the eyes and central nervous system. Workers may be harmed from exposure to hydroquinone. The level of exposure depends upon the dose, duration, and work being done.

Hydroquinone is used in many industries. It’s used as a developing agent in black-and-white photography, lithography, and x-ray films. Some examples of workers at risk of being exposed to hydroquinone include the following:

  • Manufacturing workers who use it to produce antioxidants for rubber
  • Food processing workers who use it to preserve foods such as dried fruits
  • Workers who use it to prevent polymerization during shipping, storage, and processing

NIOSH recommends that employers use Hierarchy of Controls to prevent injuries. If you work in an industry that uses hydroquinone, please read chemical labels and the accompanying Safety Data Sheets for hazard information. Visit NIOSH’s page on Managing Chemical Safety in the Workplace to learn more about controlling chemical workplace exposures.

The following resources provide information about occupational exposure to hydroquinone. Useful search terms for hydroquinone include “1,4-benzenediol,” “p-benzenediol,” “dihydroxybenzene,” “1,4-dihydroxybenzene,” and “quinol.”

NIOSH Chemical Resources

Logo of NIOSH Pocket Guide

NIOSH Pocket Guide

The NIOSH Pocket Guide to Chemical Hazards (NPG) helps workers, employers, and occupational health professionals recognize and control workplace chemical hazards.

Logo of Manual of Analytical Methods.

Manual of Analytical Methods

The NIOSH Manual of Analytical Methods (NMAM) is a collection of methods for sampling and analysis of contaminants in workplace air, and in the blood and urine of workers who are occupationally exposed.

Logo of Health Hazard Evaluations consisting of three letters: HHE

Health Hazard Evaluations

The Health Hazard Evaluation Program (HHE) conducts onsite investigations of possible worker exposure to chemicals. Search the HHE database for more information on hydroquinone.

Related NIOSH Resources

  • NIOSHTIC-2 search results for hydroquinone—NIOSHTIC-2 is a searchable database of worker safety and health publications, documents, grant reports, and journal articles supported in whole or in part by NIOSH.
  • NIOSH Worker Health Study Summaries—NIOSH conducts research to prevent illnesses and injuries in the workplace. The NIOSH Worker Notification Program notifies workers and other stakeholders about the findings of these research studies.

Selected Publications

Related Resources

International Resources