The plan to relocate Tokyo's largest wholesale market from Tsukiji to a new site in the reclaimed Toyosu area has run into a major roadblock over food safety and environmental concerns stemming from the failure to build the new facility according to a plan designed to eliminate the effects of toxic materials that were earlier detected at the site. Since the new complex is to take over the functions of Tsukiji, where 1 million tons of fish, fruit and vegetables worth ¥600 billion are traded annually and shipped across the country, officials involved must put priority on safety of the marine and agricultural products at the new market and on the prompt public disclosure of relevant information.

In 2001, then-Gov. Shintaro Ishihara decided to move the Tsukiji market functions to the Toyosu site located about 2 km south in view of the aging facilities at Tsukiji and its limited capacity relative to the amount of food products traded. In 2008, however, toxic materials, including benzene with a concentration 43,000 times the environmentally allowable level, were detected at the roughly 40-hectare site, which formerly housed a Tokyo Gas Co. plant. A panel of environmental experts commissioned by the Tokyo Metropolitan Government recommended later the same year removing the top 2 meters of soil of the entire site, replacing it with decontaminated soil and further covering the entire plot with 2.5 meters of fresh soil. This meant that all of the market structures would stand on a 4.5-meter-thick layer of clean soil.

The metropolitan government ordered the soil decontamination work in 2011 and confirmed that it was completed in 2014 at a cost of ¥85.8 billion. It was publicly explained all the while that the new market was being built in accordance with the panel's recommendation. But earlier this month, shortly after new Gov. Yuriko Koike postponed the November relocation of the Tsukiji functions to Toyosu to await the results of groundwater tests at the new site, it was found that the layer of clean soil was missing underneath the five main structures that occupy about a third of the new market site. Instead, hollow spaces had been created underground.