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Muriatic Acid Precautions

Muriatic acid, the historical name for hydrochloric acid, is a clear, colorless, mineral acid that is useful for laboratory research and industrial manufacturing processes. It is, however, a very poisonous, corrosive liquid that reacts with a variety of materials and can severely damage body tissue and organs. The concentrated acid produces toxic fumes. The acid should therefore be stored and handled with care.

  1. Chemical Composition and Reactivity

    • Muriatic acid is a solution of hydrogen chloride (HCl) gas in water, and its chemical formula is often written as HCl. It is classified as a "strong" acid because, in water solution, it is almost entirely dissociated into H+ and Cl- ions. The H+ ions are normally associated with water molecules to form hydronium (H3O+) ions. The acid reacts with many substances, including bases, metals, metal oxides and hydroxides, carbonates and amines. If decomposed by heat, the acid produces toxic chlorine gas and highly flammable hydrogen gas.

    Physiological Hazards

    • If muriatic acid comes in contact with the skin, it can cause reddening, pain, severe burns and ulcers. Contact of the acid or its vapors with the eyes can irritate, burn and damage the eyes. Swallowing the acid immediately burns the inner linings of the mouth, throat and digestive tract, and may lead to nausea, vomiting and even death. If the acid vapors are inhaled, they can cause coughing, choking and inflammation of the upper respiratory tract; in extreme cases, inhalation can lead to accumulation of fluid in the lungs (pulmonary edema) and death.

    Storage

    • Muriatic acid should be stored in a cool, dry area, away from heat, moisture and direct sunlight. The room should be well-ventilated, equipped with a good drainage system and have acid-resistant floors.

    Handling and Disposal

    • To prevent contact with the skin and clothing, wear rubber or neoprene gloves, a protective apron and impervious shoes or boots. To protect the eyes, wear safety goggles or a full facial shield. When diluting the acid, add the acid carefully and in small quantities to water. Do not add water to the acid, as that can generate extreme heat and may lead to boiling and splashing. When disposing of the acid, treat it as hazardous waste and send it to an approved waste facility.

    First Aid

    • If muriatic acid contacts the skin or eyes, use plenty of water to flush the areas of contact, over a period of at least 15 minutes. Remove any contaminated clothing. If a person has ingested the acid, give the patient large quantities of water or milk to drink, but not if the patient is unconscious; do not induce vomiting. If someone has inhaled vapors of the acid, bring the person into fresh air. In case of breathing difficulty, provide oxygen; in case breathing has stopped, provide artificial respiration. Immediately call for medical attention.

    Cleaning a Leak or Spill

    • In case of an accidental leak or spill of muriatic acid, cordon off the area, ventilate it and keep unprotected people away. Wear protective gloves, goggles, apron and shoes, as noted above. Carefully neutralize the acid with soda ash (sodium carbonate) or lime (calcium oxide) and absorb the liquid with dry sand, earth or other noncombustible material. Place the material in a container for chemical waste and send it to an approved waste facility.

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