China's authorities are investigating food safety concerns in cooking oils after an investigative report from local media revealed that tankers carrying soybean oil from a major state-owned company were also used to carry a form of coal. The report from Beijing News found it was an open secret among truck drivers that the tankers did not get cleaned in between their stints carrying edible oils and the chemicals. The Beijing News probe followed one tanker from the northwestern Ningxia region, which was carrying a type of hydrocarbon that's converted into liquid fuel. From Ningxia, the tanker traveled north and then filled up with soybean oil from Sinograin without stopping to get cleaned. I'm Charles de Ledesma.