Calcium hydroxide is the exothermic product of calcium oxide and water, according to Darrell D. Ebbing and Steven D. Gammon's "General Chemistry." It has a strong base pH and is used for many purposes, often under its more common name, slaked lime. The National Institutes of Health warns that calcium hydroxide is also toxic and can introduce serious health problems as a result of various types of exposure.
Accidental ingestion of calcium hydroxide can cause severe throat pain, a burning sensation in the mouth, abdominal pain, vomiting, bloody stool or vomit, rapidly falling blood pressure and collapse, according to the National Institutes of Health. This type of poisoning can also make blood pH too alkaline, which can cause organ damage. Poison control or other emergency services should be contacted immediately if calcium hydroxide is accidentally swallowed. Unless the victim is vomiting or exhibiting other symptoms that would make swallowing difficult or unless directed otherwise by a physician or poison expert, he should immediately be given water or milk to drink.
External exposure to calcium hydroxide can cause a variety of problems depending on the exact location of the exposure and the strength of the calcium hydroxide solution. Exposure to the skin can produce burns, painful irritation and necrosis, and exposure to the eyes may cause severe pain and vision loss that can be temporary or permanent. If calcium hydroxide is exposed to the skin, contaminated clothing should be removed, excess amounts of the chemical should be wiped off and the affected skin should be flushed repeatedly with water. Victims of calcium hydroxide exposure to the eyes should flush their eyes with water continuously for the first 15 minutes, but all cases of external exposure should receive immediate medical care. According to Absolute Astronomy, calcium hydroxide is commonly used in no-lye hair relaxer products; the FDA warns that misuse of these products may cause burning and damage to the hair and scalp.
Inhaling calcium hydroxide through the nose or mouth can also cause immediate, painful and potentially life-threatening complications. Throat and nasal passages may become painful and swollen, and the swelling may restrict airways, making breathing difficult or impossible. If the calcium hydroxide particles are carried all the way to the lungs, this may further complicate breathing. Victims of this type of exposure should be taken immediately to a fresh air environment, and emergency services should be contacted right away. Administration of oxygen and emergency respiratory assistance may be required.
According to the Material Safety Data Sheet on calcium hydroxide, chronic exposure to the skin may also cause health problems. As calcium hydroxide is an active ingredient in some hair relaxers, these symptoms could potentially arise as a result of prolonged, regular use of those products. Dermatitis and severe skin irritation are common symptoms of this type of exposure.