At least 100 people were killed and more than 200 injured in an explosion at a waste-burning site in Benin's largest city and economic capital Cotonou, the media reported on Friday.The blast which occurred on Thursday resulted from rotten flour which did not burn off fully at the landfill site about 20 km north of Cotonou, Xinhua news agency reported.The heavy casualties were caused because locals rushed to fetch the rotten flour after authorities monitoring the burning left the site, it reported.Earlier, under supervision by police and customs officials, the rotten flour that had been confiscated at the Cotonou customs was carried to the site for burning.The death toll could rise further because some of the injured were in critical condition due to severe burns.