it carries the bile from the liver to the duodenum. when i started to investigate the printing company in osaka, i found five workers between the age of 20 and 50 had bile cancer. eventually we discovered more than 10 workers at the company had the disease. experts carried out further studies. they found the incidence of bile duct cancer at the company was more than 600 times the average among average men. >> how do scientists know the chemicals in these cleaning agents though actually harmed the workers? >> well, the chemicals are called dichloromethane and dichloropropane. they're used in the printing industry. they're not used just in the printing industry but also used for cleaning semi-conductors, metals, and dry cleaning industry among other industries. scientists think once people inhale this chemical, the substance changes the nature of an enzyme called gst. it releases a carcinogenic substance. government scientists have yet to reach a conclusion but they say it is highly likely either one of the two chemicals or both of them

> this type of cancer is found in people over the age of 60 in the tube that carries bile to the duodenum. but i found five workers between the age of 20 and 50 had bile duct cancer. we discovered ten workers at the company had the disease. after carrying out further studies they found the incidence of the cancer is more than 600 times the average of the japanese men. >> how do the scientists know the chemicals in the cleaning agent harm the workers? >> the chemicals are usein the prting industry. they are also used not just in the printing industry but also used for cleaning semiconductors, metals and dry cleaning industries. scientists think once people inhale the chemical, the substance change the nature of an ensubsidize called dst. the government scientists have yet to reach a conclusion but it is highly likely one or the o chemicals or bh are causing these bile cancer cases. >> this is used in many industries, semiconductors and cleaning. japan has regulations to protect people from these agents. how can this kind of thing happen? >> right, gene. there are two too many chemicals on