Japanese drugmaker Kobayashi Pharmaceutical says water accidentally leaked into a tank making "beni-koji" red yeast rice supplement and other products' ingredients at its factory.

But the company says it remains unknown whether the leak has anything to do with the kidney and other health problems among those who took supplements and other products with "beni-koji" ingredients.

A compound believed to be puberulic acid, which can be produced from blue mold, has been found in "beni-koji" raw materials produced last year at the factory in Osaka City. The factory was shut down in December because it was dilapidated.

Kobayashi Pharma says it produces "beni-koji" raw materials by culturing steamed rice with a particular fungus in a tank in the factory.
The outside of the tank was partially immersed in a warm water bath, and that water appears to have leaked into the vessel.

The company says it replaced tank parts and discarded the "beni-koji" raw materials inside.

The company has not disclosed when the incident occurred.

Officials of Osaka City and others inspected the factory last month and are looking into hygiene management and production processes at the factory.