The only thing good that can come out of a deadly catastrophe is that we learn from the tragic experience so as to reduce, if not prevent, the effects of another such disaster in the future.

This seems to be happening with regard to the fatal 2:30 a.m. Jan. 6, 2005, Graniteville freight train wreck that ruptured one of three chlorine-filled tankers, causing the release of about 60 tons of chlorine.

The deadly chemical condensed into a thick cloud of gas that hugged the ground as it spread around the area and to a nearby textile mill. The toll was nine people dead, 71 hospitalized and more than 500 treated in emergency rooms. Although most injured victims recovered quickly, some suffered severe lung damage and others are still being monitored by health authorities.

What hospital and public health agencies learned from the Graniteville disaster is how to be better prepared for such emergencies. More specifically, hospitals must learn how to quickly recognize signs of chlorine exposure and make sure that mechanical ventilators are "an integral component of emergency planning."

Though small, accidental exposures to chlorine gas are not unusual, the Graniteville accident was one of the largest community exposures on record.

"It was a tragic disaster that shows us what a significant challenge a large-scale chlorine gas release poses to health care facilities," said Wisconsin University's Dr. David Van Sickle, lead author of a study funded by the federal Centers for Disease Control and the South Carolina Department of Health and Environmental Control.

The U.S. Department of Homeland Security also has an interest in learning from the study because of concerns that hundreds of chlorine storage tanks scattered around the country could be attractive targets for terrorists. If such a tank were attacked in a high-density community, says an agency spokesperson, an estimated 10,000 people would die and 100,000 hospitalized.

That's scary. Security experts are on guard against terrorists trying to sneak "dirty" chemical or toxic bombs into the country. The nation's chlorine tanks are ready-made chemical bombs; terrorists need only find ways to set them off.

If studies of the Graniteville tragedy mitigate or lessen the impact of such an occurrence then at least something good will have come out of it.