Twenty-seven cars of a 59-car Norfolk Southern freight train hauling molten sulfur, phosphorus, and toluene derailed near Ligonier, Indiana recently.

(Reuters) - Indiana environmental officials are monitoring the aftermath of a freight train derailment and fire in northern Indiana Tuesday morning that may have caused hazardous substances to enter the Elkhart River.

Amy Hartsock of the Indiana Department of Environmental Management said it is too soon to know if any of the molten sulfur or toluene carried by some train cars entered the river, which is fed by a nearby wetland.

Environmental officials do not know if foam seen on the river is a result of the derailment. "We are watching it very closely," Hartsock said. A conservation officer on the scene has so far not seen any damage to water fowl or aquatic life, she said.

The train, consisting of 59 freight cars and three locomotives derailed early Tuesday near Ligonier, Indiana after leaving Elkhart, Indiana for Bellevue, Ohio. No injuries were reported, according to Norfolk Southern spokesman David Pidgeon.

The derailment affected more than 400 Amtrak passengers on two trains heading to Chicago, according to Amtrak spokesman Marc Magliari. One train was detoured and continued to Chicago -- passengers on the second train were put on buses, Magliari said.

Hartsock said that the fire has died down and emergency management officials have been able to get closer to the site.

About six families in the rural community were asked to evacuate their homes as a precaution, Hartsock said.

Molten sulfur is used for making plastics, dyes, detergents, pharmaceutical products and fertilizer and toluene is used in the making of paints, paint thinner, fingernail polish, rubber and other materials, according to Pidgeon.

Points to consider:

The derailment resulted in some of the cars to burst into flames, and nearly 200,000 pounds of molten sulfur to spill. Fire crews decided not to try to extinguish the fires and instead let the blazes burn themselves out because putting water on the flames might cause an unwanted reaction. Consider that the transportation of hazardous materials is an important problem due to its frequency. Approximately 1.7 million carloads of Hazmat transported by rail each year. These materials, or dangerous goods, include explosives, gases, flammable liquids and solids, oxidizing substances, poisonous and infectious substances, radioactive materials, corrosive substances, and hazardous wastes. Remember that due to the nature of most of these chemicals, they can pose hazards of explosion, toxic release, and fire.

(Reporting By Susan Guyett; Editing by Mary Wisniewski)