Residents in a county in east China's Jiangsu Province left their homes in a mass exodus early Thursday following rumors about a chlorine gas leak at a nearby chemical plant and a possible explosion, The Jinling Evening News reports.

People of various ages carrying luggage were seen busy making their way towards the county seat as early as one o'clock on the streets and roads of Chenjiagang and Shuanggang areas of the county in Yancheng city. Anonymous local residents called the Jiangsu-based newspaper in the early hours, saying they abruptly left their homes after a rumor surfaced that a chemical plant in the Chenjiagang industrial park was leaking chlorine and an ensuing explosion could occur.

A mobile video shot provided to the newspaper showed the gridlock that ensued after residents tried to flee the area on foot and by car. The newspaper cited an anonymous netizen who estimated that more than 10,000 people were on the roads trying to leave the area as quickly as possible. Other media reports put the number at more than 100,000.

In the chaotic scene, a motorized tricycle with more than 20 people onboard fell into a river, resulting in the deaths of four, including a three-year-old boy, a resident surnamed Pan related to the paper in a telephone call-in. A few relatively minor accidents also occurred in the rainy-snowy weather.

A county government official website later released information denying the chemical explosion story. Police have started searching for those who spread the rumor, the report said.

Most residents returned to their homes in the morning, while the local environmental protection bureau responded to various reports about pungent smells in the area in the early hours of Thursday.

A chlorine gas leak had occurred in the industrial park on the morning of November 23, 2010, affecting more than 30 employees at a chemical company who were downwind of the leak. No deaths were reported in the incident, which lasted about five minutes after a worker mishandled a valve.