Sodium hydroxide (NaOH), also commonly referred to as lye or caustic soda, is an inorganic chemical compound manufactured for use in a number of industries and it can be found in some household products. The National Institute for Occupational Safety and Health (NIOSH) describes sodium hydroxide as being caustic and having no smell. At room temperature, sodium hydroxide appears as solid white crystals that absorb water from the air.

The Agency for Toxic Substances and Disease Registry (ATSDR) reports that it is used to manufacture soaps, rayon, paper, explosives, dyestuffs and petroleum products. It is also used in processing cotton fabric, laundering and bleaching, metal cleaning and processing, oxide coating, electroplating and electrolytic extracting. Sodium hydroxide is also commonly present in commercial drain and oven cleaners.

Some examples of workers at risk of being exposed to sodium hydroxide according to NIOSH 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

ATSDR lists a number of ways people can be harmed by exposure. These include severe burns to tissue from contact and spontaneous vomiting, chest and abdominal pain, and difficulty swallowing from ingestion. The agency also states that inhalation of low levels of sodium hydroxide as dusts, mists or aerosols may cause irritation of the nose, throat and respiratory airways. Inhalation of higher levels can produce swelling or spasms of the upper airway leading to obstruction and loss of measurable pulse; inflammation of the lungs and accumulation of fluid in the lungs may also occur. Long-term exposure to sodium hydroxide in the air may lead to ulceration of the nasal passages and chronic skin irritation.

To help protect workers, the Occupational Safety and Health Administration (OSHA) has set a Permissible Exposure Limit (PEL) and NIOSH has a Recommended Exposure Limit (REL).

These are just a few of the many things to know about sodium hydroxide and potential occupational exposure risks. To learn more about this or other industrial hygiene, environmental, health or safety issues, please visit the websites shown below.

Clark Seif Clark https://www.csceng.com
EMSL Analytical, Inc. https://www.emsl.com
LA Testing https://www.latesting.com
Zimmetry Environmental https://www.zimmetry.com
Healthy Indoors Magazine https://www.healthyindoors.com