In China, a number of incidents have occurred where state limits were exceeded by large amounts or where the wrong pesticide was used. In August 1994, a serious incident of pesticide poisoning of sweet potato crops occurred in Shandong province, China. Because local farmers were not fully educated in the use of insecticides, they used the highly-toxic pesticide named parathion instead of trichlorphon. It resulted in over 300 cases of poisoning and 3 deaths. Also, there was a case where a large number of students were poisoned and 23 of them were hospitalized because of vegetables that contained excessive pesticide residues.