NIOSH logo and tagline

Sodium Hydroxide


CAS No. 1310-73-2

Sodium hydroxide (NaOH) has no smell. It is made of solid white crystals that absorb water from the air. Sodium hydroxide is caustic. Sodium hydroxide can harm workers who come in contact with it. The level of harm depends upon the amount, duration, and activity. It can burn the eyes, skin, and inner membranes, and cause temporary hair loss.

Manufacturers may use sodium hydroxide to produce soaps, rayon, paper, products that explode, dyes, and petroleum products. Other tasks that may use sodium hydroxide include processing cotton fabric, metal cleaning and processing, oxide coating, electroplating, and electrolytic extraction. It is often present in commercial drain and oven cleaners.

Some examples of workers who are at risk of exposure to sodium hydroxide include those who

  • Use bleach, oven cleaners, and drain cleaners
  • Work in food processing plants
  • Work in public water treatment plants
  • Use sodium hydroxide for making paper, glass, detergents, soaps, and other products
  • Mine alumina and produce aluminum

NIOSH recommends that employers use a Hierarchy of Controls to prevent injury.

If you work in an industry that uses sodium hydroxide:

  • Read the chemical label and the Safety Data Sheet. They explain how it can harm you and how to protect yourself.
  • Visit NIOSH’s page on Managing Chemical Safety in the Workplace, where you can learn more about preventing contact with chemicals in the workplace.

The following resources provide information about workplace exposure to sodium hydroxide. Useful search terms for sodium hydroxide include “lye”, “caustic soda”, “soda lye”, and “sodium hydrate”.

NIOSH Chemical Resource

Related NIOSH Resources

Selected Publications

Related Resources

International Resources