First Post: Cloud from hydrochloric acid in Texas City

"A toxic cloud that formed after 300 gallons of hydrochloric acid leaked at a plant due to a tank rupture which sent nine people to the hospital and forced thousands of residents to stay indoors for a few hours."

Common Routes of Hydrochloric Acid Exposure

• Inhalation: The most common way for hydrochloric acid to enter the body is through the respiratory
  system. Signs and symptoms of hydrochloric acid inhalation can include:
  
  • Coughing
  • Choking
  • Burning of the throat

Contact with the Skin: Hydrochloric acid can irritate the skin and cause chemical burns ranging from mild to severe depending on the concentration of the hydrochloric acid solution.

Contact with the Eyes: Hydrochloric acid, even with short-term exposure, can irritate the eyes and cause burning, swelling, tearing of the eyes, blurred vision, photophobia, sloughing of the surface cells of the eye, and may cause blindness.

Ingestion: Immediate burning in the mouth and throat occur when hydrochloric acid is swallowed. Ingestion of concentrated solution can cause severe pain in the mouth, chest and abdomen, nausea and vomiting.

So assuming we were the plant safety person what would be the series of steps we would take to contain such a situation?

From OSHA:

1. Notify safety personnel.
2. Remove all sources of heat and ignition.
3. Ventilate the area of the spill or leak.
4. Stop leak if this can be done without risk. If the source of leak is a cylinder and the leak cannot be stopped in place, remove the leaking cylinder to a safe place in the open air, and repair leak or allow cylinder to empty.
5. All spills on land involving liquid hydrogen chloride or hydrochloric acid should be contained, if possible, to prevent entry into bodies of water or sewer systems. Vapors can be dispersed with water fog or spray. Do not put water directly on leak or spill area.
6. Neutralize spills with crushed limestone, soda ash, lime, or sodium bicarbonate. After neutralizing, take up with sand or other noncombustible absorbent material and place into closed containers for later disposal.
7. For large liquid spills, build dikes far ahead of the spill to contain the hydrogen chloride for later reclamation or disposal.

The current Occupational Safety and Health Administration (OSHA) permissible exposure limit(s) (PEL[s]) for hydrogen chloride is 5 ppm (7 milligrams per cubic meter (mg/m(3))) as a ceiling limit.

OSHA is currently developing requirements for medical surveillance for employees who work with and are at a risk of being  exposed to hydrogen chloride.

In this case, there was a huge toxic cloud which formed over the area. More than 45,000 residents of Texas City were ordered  to remain indoors, turn off air conditioning units and make sure all windows and doors were closed until the vapor cloud dissipated. The leak occured at 4:19 a.m local time and the stay-indoors order was lifted off at 6:00 a.m.