Nov 2 (Reuters) - Hundreds of residents outside Louisville, Kentucky, were kept from their homes for a third day on Friday as authorities allowed a chemical fire triggered by a train derailment to burn itself out, local emergency officials said.
The freight train, which was carrying butadiene and styrene, jumped the tracks on Wednesday about 30 miles (50 km) south of Louisville near the small Kentucky town of West Point and the Fort Knox military post.
Workers responding to the derailment accidentally ignited the butadiene, a flammable gas, prompting officials to order the evacuation of 155 nearby residences.
Three workers were injured in the fire. Two remained hospitalized on Friday while the third had been released, according to Jody Duncan, spokeswoman for the Louisville/Jefferson County Emergency Management Agency.
Firefighters were allowing the butadiene-fueled blaze to extinguish itself, a process Duncan said could take several more days. As a result, the evacuation order issued on Wednesday remained in effect for a third day.
But a separate advisory urging people living within 5 miles (8 km) to stay indoors was lifted on Thursday. Workers were able to safely remove the styrene from the train wreck on Thursday night, Duncan said, and to truck it away. (Writing by James Kelleher; Editing by Cynthia Johnston and Mohammad Zargham)