Inadequate inspections on manufacturers dumping toxic waste have resulted in hundreds of thousands of tons of dangerous chemicals festering outside factories and near industrial sites across the country, according to scientists attending a recent international conference on toxic waste held in Crete.

“Unfortunately, the main problem with the management of toxic waste in this country is that we have no idea what is really going on,” Vangelis Gidarakis, the director of the University of Crete’s toxic waste laboratory, told the Kathimerini newspaper.

According to Mr. Gidarakis, the chief barrier to progress is that there is no consensus about the size of the problem. The Environment and Public Works Ministry says there are some 600,000 tons of toxic waste in Greece. The European Union puts this figure at 1 million tons. Environmental groups say the real figure is closer to 10 million tons.

“No one really knows what volumes we are talking about,” Mr. Gidarakis said. “Huge amounts of waste are polluting the ground and penetrating the water table and subsequently the food chain” he said, adding that the ministry, local authorities and large manufacturers were all to blame for the situation.