For all its benefits, domestic and industrial uses, Sodium Hydroxide or lye is not a chemical to be handled easily. It is the strongest base (NaOH) that can be extremely dangerous to the human body when exposed to skin or ingested or inhaled. White and odorless in color, it is a non-volatile aqueous solution when combined with water. Though not readily flammable, it is highly reactive, causing corrosion in all places it comes in contact with. Owing to all these hazardous properties, you need to guard yourself well when you use lye or caustic soda. Though goggles, gloves, lab apron, long sleeve etc serve as good guards, nothing works better than avoiding contact, ingestion, inhalation or constant exposure to the chemical.
Sodium Hydroxide hazards: A quick glance at the hazards identification for the chemical in the Material Safety Data Sheet (MSDS) says – “Poison. Danger. Corrosive. Maybe fatal if swallowed. Harmful if inhaled. Causes burns to any area of contact. Reacts with water, acids and other materials.” The Safety T Data health ratings show lye’s poison rating as 4 and contact rating (corrosive nature) as 4. Though flammability, reactivity etc are given lesser ratings, the chemical is termed as potentially dangerous.
If this is the truth about lye or caustic soda, why do we use it and how do we handle the hazards? Lye cannot be eliminated from our lives as it is used in a wide array of applications – from soap making, processing of cotton, production of rayon, production of petroleum and natural gas to vegetable oil refining, water treatment, manufacture of glass, adhesives and a whole lot of other things. With such a spectrum of usage, one cannot ignore lye’s benefits. So, the best way out is to learn how to deal with the hazards.
1. Poisonous when ingested: Lye is an extreme poison when swallowed or ingested into the body. It can corrode every region of the body it passes through, damaging at the most the mouth cavity, throat, stomach and all tissues it comes in contact with. A study on whether it causes cancer when ingested has shown that the burning of tissues can have carcinogenic effects after a long time, say a period of 10 years. On ingestion, one will experience bleeding, vomiting, diarrhea, fall in blood pressure etc.
When you identify that one has been ingested with lye, give plenty of water and milk. Seek immediate emergency medical attention. Never give anything if the person turns unconscious on consumption of lye.
2. Harmful when inhaled: Reports of inhalation suggest that the compound has the ability to cause severe irritation in the respiratory tract lining, leading to a lung injury known as pulmonary edema or accumulation of fluid in the lungs. Symptoms may include sneezing, runny nose and sore throat, severe pneumonia can also be a result.
When you identify that a person has inhaled lye, move him to fresh air immediately. Give artificial respiration and call a physician. He may experience a tightness in the chest area as a reaction to the body’s defense against the irritant.
3. Corrosive on contact: Sodium Hydroxide can be corrosive on all areas it comes in contact with. This can include everything from your skin to your wall paint, flooring and even fabric. Severe burning, ulceration and skin scarring can occur when the chemical comes in contact with your skin. Excessive exposure can result in a deeper injury. When you know that you have contacted lye, flush your skin with plenty of water for about 15 minutes until the heat and irritation subside. Also remove all the contaminated clothing and avoid further contact with skin or sensitive areas like face or eyes. Call the physician immediately to avoid further burning of skin.
4. Vision impairment with eye contact: Lye can be very harmful on the eyes, causing glaucoma, cataract or even permanent vision impairment. When you experience eye contact, flush your eyes immediately with plenty of water, lifting the upper and lower eyelids occasionally. Lye can cause clouding of cornea and loss of normal vision, which may, if untreated, lead to permanent blindness.
5. Constant exposure to damage tissues: Avoid constant exposure of caustic soda. Continual skin contact, even if minimal, can lead to dry, cracked, scarred or inflamed skin. Chronic respiratory exposure can also damage your lungs and block airways.
6. Flammability: Sodium Hydroxide, as such, is not inflammable, but can react and ignite combustible substance nearby. It reacts with other metals to form hydrogen which ignites in the presence of oxygen. So avoid keeping flammable substances nearby.