The Tokyo Metropolitan Government on Monday revealed it learned in June that the concentration of a toxic substance at the proposed site of a new fish market in Toyosu, Koto Ward, was 115 times higher than in a previous inspection but withheld the information for five months from a panel of soil pollution experts.
The toxic substance, benzopyrene, is a carcinogen found in coal tar and automobile exhaust. It is one of 22 chemicals designated as posing a high health risk by the Air Pollution Control Law, although there are no regulations stating its acceptable level, an Environment Ministry official said.
The Tokyo government wants to move the world-famous fish market from the Tsukiji neighborhood to the new site by 2014.