More than 150,000 workers in Greece have been exposed to the carcinogenic material asbestos and the banned substance still exists in many homes, experts said at a conference in Athens yesterday. «We urgently need to develop a national strategy for asbestos,» said Christina Theochari, head of the environment department of the Confederation of Greek Labor (GSEE), which organized the conference with the Technical Chamber of Greece. Labor Minister Savvas Tsitouridis said that he is preparing a draft law to regulate companies which remove asbestos from buildings. The construction material has been banned by the European Union but until recently was widely used in the building of Greek homes, factories and schools. Authorities face the task of removing the material from public buildings. Officials estimate that it will take until next year to clear asbestos from some 500 schools where the material can still be found.