The Health and Welfare Ministry kept secret a report compiled in February that revealed a high concentration of a hormone-disrupting substance has been detected in boxed lunches sold at convenience stores, sources close to the case said Monday.
While withholding the information from the public, the ministry's Food Chemistry Division secretly released the data to related industries earlier this year, urging them to deal with the problem, the sources said.
The substance — diethyl hexyl phthalate (DEHP) — is believed to damage the reproductive systems of animals. Experiments on animals have shown that DEHP reduces the production of sperm. It is widely used in Japan to make plastics softer, mostly in vinyl chloride.