A freight train carrying hydrochloric acid derailed in Lafayette, LA Saturday, causing a leak that forced 3,500 people to evacuate their homes and businesses. A nursing home was also evacuated.

In high concentrations hydrochloric acid forms an acidic mist. Both the mist and the solution have a corrosive effect on human tissue. Hydrochloric acid can damage respiratory organs as well as eyes, skin and intestines. The Environmental Protection Agency rates and regulates hydrochloric acid as a toxin.

Toxic cloud
An estimated 8,000 to 10,000 gallons of the acid was spilled. The acid formed a yellowish pool at the site of the derailment and sent a toxic cloud over the area. At least five people, including two railroad workers, were taken to a nearby hospital with skin and eye irritation.

A nursing home with 161 residents was evacuated, Dr. Jimmy Guidry, the state health officer, said. Those too frail to travel were taken to area hospitals.

Police walked door-to-door notifying residents of the mandatory evacuation in an area with an estimated population of 3,500 people and advised to take enough supplies for approximately 48 hours. The Red Cross set up a shelter at a high school.

In all, six cars of the train derailed, but only two developed leaks failed. Another car carrying ethylene oxide, used in agricultural products and as a sterilizer for medical supplies, was overturned but was not leaking, said Rodney Mallett, a spokesman with the Louisiana Department of Environmental Quality.

The Burlington Northern Santa Fe Railroad was using lime to neutralize the hydrochloric acid. Cleanup workers will then either dig or vacuum up the acid and lift the cars back onto the track.

For training on response to hydrochloric acid incidents, Sulfuric Acid & Hydrochloric Acid safety training video.