The unease was sparked Friday, when bystanders saw government workers at a factory using robots to examine a cobalt-60 irradiator that had malfunctioned. The machine is used mainly for sterilizing pepper powder, flavoring used in instant noodles and garlic.
Within hours, alarm spread as people began hearing word that explosions occurred at the irradiation plant.
"There was chaos on the streets from about 2:30 p.m. until dark," said Zhu Zhihai, manager of a garlic-processing factory where all 30 employees rushed away. "All kinds of vehicles were going out of the county - farm vehicles, motorcycles and cars.
People were in a hurry and they didn't take anything with them." Zhu, who estimated that about a third of the county's 1 million people fled, said he didn't leave because his friends at the local environmental protection bureau told him there had not been a disaster.
An official at the Qi county government office said only "a small portion of people left" and refused to give his name or any other details.
Rumors can run rife in China, where many do not trust local officials and the government-controlled media because they downplay or in some cases boycott negative news fearing it will trigger social unrest.
During the 2002-03 outbreak of SARS, the government was slow to publicly acknowledge the scope of the country's outbreak, unintentionally creating a fertile environment for misinformation. Hundreds of thousands of people received a text message saying that a baby who purportedly spoke immediately after birth proclaimed that firecrackers and "green bean soup" could prevent infection.
The lack of credible, free-flowing information can have more serious consequences. Last month, reports that a woman who was Han Chinese - the country's ethnic majority - had been raped by one or more Muslim minority factory workers triggered a deadly brawl. The tensions exploded into more ethnic violence on July 5 in China's predominantly Muslim West that left almost 200 people dead.
A worker at Zhu's garlic factory who would only give his surname, Liu, said when he asked people why they were running, they told him that explosions had occurred at the factory with radiation equipment.
"People were saying 'If you are too slow, you will die,"' said Liu, who jumped on his motorized bike and began making his way to his house 6 miles (10 kilometers) outside the county with his wife and two children. "The road were filled with vehicles. Other people were on their bikes with their families or carrying sheep and pigs."
Some went as far as the capital city of Zhengzhou, about 60 miles (100 kilometers) away and although most had returned by Monday, some parents were keeping their children away for a few more weeks.
Li Chunsheng, deputy director of the Environmental Protection Bureau of Kaifeng, which oversees Qi county, said in a statement posted on the government Web site Saturday that the irradiator problem "will not cause any harm to the public."
Li said the irradiator malfunctioned June 7 when its protective shield was knocked askew as a batch of peppers was being sterilized. As a result, the device couldn't be put properly into its storage well, he said.
The machine, which is operated by remote control, was in a sealed room secured with concrete and two layers of stainless steel, Li said. Daily inspections since have shown no leaks, he said.
An official at the Henan environmental protection bureau, who gave only his surname Zhang, said the incident was not publicized because it was a mechanical malfunction.
