A Brief Explanation on the Health Effect and Safety Hazards of Sodium Hydroxide

Sodium hydroxide is a strong, colourless, corrosive, and odourless liquid with the chemical formula NaOH. It is often used in industry for the production of chemicals and for cleaning purposes. It is used in industries like detergents, textile, and leather industries as it is a very effective cleaning agent for all kinds of waste materials. It has many industrial uses, and its production volume is exceeded only by ammonia and chlorine. This article discusses the health hazards associated with exposure to sodium hydroxide in humans, mainly concentrated on its corrosiveness, skin irritant properties, and chemical burns.

Sodium Hydroxide

Sodium hydroxide is a white or colourless volatile liquid with a pungent odour at room temperature. It has the chemical formula of NaOH, and its molecular weight is 137. It exists as an ionic compound that consists of a cation (Na+) and an anion (OH–). It dissolves without heating in water, forming sodium hydroxide and water solution that releases heat when exposed to air (exothermic). Sodium hydroxide (NaOH) is widely used as a chemical reagent, e.g., an oxidising agent for some organic compounds. It is also used as a bleach and corrosion inhibitor for metal parts in their pure form.

Sodium hydroxide (NaOH) is an alkali. It shows an exothermic reaction when reacted with a base.

Health Effects and Safety Hazards of Sodium Hydroxide

Prolonged Skin Contact: A few industrial uses of sodium hydroxide can result in prolonged skin contact and localised chemical burns known as phosphoric acid (NaH2PO3) burns. These chemical burns are caused by the release of highly concentrated phosphoric acids from the base, causing intense pain and swelling to exposed areas of the body.

Chemical Burn: Another type of chemical burn known as corrosive burn also occurs because of this chemical. The corrosive burns to the skin and eye are caused by the release of highly concentrated acids from the base.

Eye Irritant: Sodium hydroxide is also an eye irritant and, as with other alkaline solutions, a strong enough concentration can be corrosive to human tissue. 

Inhalation: Inhalation of sodium hydroxide can result in irritation of the nose and throat, and pharyngeal edema may develop.

Acute and Chronic Effects: There is limited information available about the acute and chronic effects of sodium hydroxide. Sodium hydroxide can also irritate mucous membranes, resulting in irritation of airways and lung damage. Excessive dermal exposure to concentrated solutions can result in chemical burns, and the inhalation of dust and fumes caused by corrosion can result in pneumonitis. 

Reproductive Effects: A study reported that pregnant rats exposed to 25-30 times the recommended occupational exposure limit (NOEL) were found to have a higher incidence of malformations (cleft palate). Sodium hydroxide is classified as a reproductive toxicant.

Damage to Eyes: If the excess quantity is delivered to the eyes, it can cause chemical burns and blindness, resulting in permanent damage to the eye’s tissues. The corneal epithelium is especially vulnerable due to its thinness and smooth surface. Although most eyes are not completely destroyed by this corrosive agent, vision is often reduced (due to conjunctivitis) or impaired (due to lid retraction), and vision may never be restored.

Gastrointestinal Irritation: Sodium hydroxide can cause gastrointestinal irritation, which can be a precursor to the development of ulcers and stomach cancer, and oral intake of large amounts can also lead to diarrhoea and gastric pain. 

1% Sodium hydroxide solution in water can cause chemical burns, serious eye damage, and respiratory tract irritation if the concentration of NaOH is high. 

Evacuation Problems: Ingestion of small amounts of the chemical can result in evacuation problems and irritation of the gastrointestinal system; however, swallowing very large quantities may be fatal.

Precautions to Take While Working with Sodium Hydroxide:

• Wear chemical goggles and impermeable clothing and shoes.
• Wear a respirator or mask while handling concentrated solutions of sodium hydroxide.
• Use well-ventilated areas to avoid exposure to the vapours from sodium hydroxide.
• Avoid contact with skin, eyes, and clothing.
• Do not smoke or eat during work involving sodium hydroxide as it can irritate the gastrointestinal system if swallowed.
• Wear protective gloves if handling sodium hydroxide.
• This chemical can cause skin irritation, so avoid direct contact with skin and always wear impermeable clothing and rubber gloves when handling this chemical.
• Do not inhale its vapours. If used in excess, sodium hydroxide may cause corrosion of the skin, eyes, lungs, and stomach. Sodium hydroxide may also cause rashes and burns to the skin. It can cause damage to our nervous and sensory systems too.

Conclusion

The study confirmed that sodium hydroxide is a highly corrosive agent which can cause damage to skin, eyes, and internal organs if swallowed or absorbed through the skin. It also leads to irritation of mucous membranes, which may lead to respiratory illness and cancers in the body. In case of any exposure, first aid should be administered immediately by washing the affected region with soap and water. First aid for eye exposure should be administered immediately by flushing the affected area with water for at least 15 minutes. In case of major issues, a visit to the doctor is mandatory.