There is nothing remarkable about Tangshan, a small outpost on the road between the eastern cities of Shanghai and Nanjing. But the town has now attained a certain notoriety - as the site of one of China's worst food poisoning cases in recent memory. No one knows how many residents have died since authorities imposed a news blackout on Saturday's incident save for official releases by the Xinhua news agency. With the key 16th Communist Party Congress approaching in early November, the government is keen to keep a lid on signs of social discord. A journalist for the Yangtze Evening News said officials had ordered local media not to report independently on the case. More then 200 people, many of them schoolchildren and migrant construction workers, are believed to have fallen ill and 'a number' have died from eating breakfast snacks made by a local food supplier and sold wholesale to schools, factories and the Heshengyuan soy milk store in the centre of town. The China Daily reported yesterday that the incident was caused by rat poison, which might have been deliberately mixed into the traditional Chinese cakes and fried dough. Two days after the incident, rumours abounded that police had taken into custody the operator of a neighbouring enterprise who was angered by his rival's success. Officials from Nanjing city government and the local police declined to comment. The case is an example of the kind of challenge facing the government as rapid development and a growing income gap causes resentment between rich and poor, even within one community. In March last year, a man fired from his job at a cotton mill set off a string of blasts in the industrial city of Shijiazhuang, killing at least 108 people. Food poisoning cases are rampant in China, caused not only by poor sanitation but by excessive cost-cutting. State media have carried reports of baked goods made with industrial oil, flour mixed with detergent and spirits brewed with methanol. Food poisoning killed 146 people in China last year and affected another 15,000, according to official figures. Tangshan residents told horror stories about the poisoned people vomiting and coughing up blood. 'Americans had September 11. We had September 14,' said taxi driver Liu Xiumin, who drove one of the young victims to hospital on Saturday. The narrow alley where the food was prepared remains blocked off by makeshift barriers and police cars. On a nearby street, the Heshengyuan shop is shuttered although other shops are doing brisk business. At the Zuochang Middle School, which bought food from the supplier, the high gates are closed. Tangshan has called off classes at the school until tomorrow because of the number of victims among its students. Zhong Guobo, 15, who attends the school, counts himself among the lucky ones since he was not attending classes last Saturday. Only the third-year students taking a special class to prepare for high-school entrance examinations were at the school. 'I'm a little scared,' he admitted. At the construction site for the Donghulidu property development, where workers also ate the tainted breakfast food, security guards have closed off the area. Authorities already have a tough stance on crime, but given the numbers of people poisoned, residents hope the case will have deep repercussions at the highest level of government. 'We can curse the leaders, but what else can we do?' said one.