Tokyo Gov. Yuriko Koike revealed Saturday that the foundations of three main structures of the Toyosu market in Koto Ward that was built to replace the famed Tsukiji fish market were not filled with clean soil as the public was previously told.

At a hastily called news conference, the governor said she will ask experts to re-examine whether the Toyosu site is safe for both consumers and employees.

The finding could further delay the relocation of the Tsukiji fish market in Chuo Ward, which was originally planned to take place on Nov. 7. Koike postponed the move to at least January shortly after becoming Tokyo governor on July 31.