Safety Hazards of Hydrochloric Acid

Hydrochloric acid is a dangerous substance.

Hydrochloric acid (HCI) is a clear, colorless, highly acidic, nonflammable, corrosive and poisonous solution of hydrogen chloride and water. It has many major industrial uses It is classified as a hazardous material by the U.S. Department. Persons working with or around hydrochloric acid should strictly adhere to safety precautions. These include wearing properly fitting safety glasses and gloves and ensuring proper ventilation.

Respiratory System Dangers

Inhaling hydrochloric acid vapors may cause choking, coughing and inflammation of the throat, nose and upper respiratory tract. Severe cases, typically as a result of either prolonged exposure or high concentrations of the acid, may lead to pulmonary edema (fluid in the lungs), shock, circulatory failure and even death.

Eye Dangers

HCI vapors are noticeably irritating to the eyes, and are often the first sign of the presence of the acid in the area. Prolonged exposure is likely to cause painful burning and could result in temporary damage to the eyes. Actual contact to the eyes may cause severe burns, reduced vision, permanent damage and/or blindness.

Skin Dangers

Exposure to hydrochloric acid may cause irritation, redness, swelling, pain and severe skin burns. Contact with hydrochloric acid can cause deep ulcers on the skin and temporary or permanent skin discoloration.

Ingestion Dangers

Swallowing hydrochloric acid may result in pain, nausea, extreme thirst, diarrhea and vomiting, as well as burns in the mouth, throat, esophagus and gastrointestinal tract. In significant amounts, ingestion may result in corrosion of the mucous membranes, circulatory collapse and death.

Metabolic Dangers

An acid-base imbalance could occur as a result of an increase in the concentration of chloride ions in the blood after ingesting high levels of hydrogen chloride, although this condition is rare.

Acute Concentrations

For most people, exposure to hydrochloric acid levels of 50 to 100 ppm is tolerable for less than one hour. Someone exposed to levels greatly exceeding the tolerable threshold may experience an immediate onset of rapid breathing, coughing up blood, anxiety, excessive sweating, narrowing of the bronchial tube, blue coloring of the skin and accumulation of fluid in the lungs. Medical attention should be sought immediately.

Chronic Exposure

Exposure to even low levels of hydrochloric acid over a prolonged period of time may have adverse results to the skin (dermatitis, photosensitization) and teeth (discoloration of teeth and erosion of exposed incisors).

Dangers to Children

Since children have relatively smaller airways, they may be more vulnerable to the corrosive effects of HCI. Also, children have relatively higher metabolic rates than adults; as a result, the odds that exposure to toxicants such as HCI will be disruptive to normal metabolism may be greater.

References

• Centers for Disease Control: NIOSH Guide to Chemical Hazards
• Agency for Toxic Substances and Disease Registry: Hydrogen Chloride
• Occupational Safety and Health Administration: Health Guidelines
• Pipeline and Hazardous Materials Safety Administration: Hazardous Materials Information System