Chinese cooking oil siphoned from restaurants' waste tanks and stripped out of raw sewage is being resold on the cheap and has for years tainted approximately one out of every ten meals cooked in the eastern nation, according to a recent study.

The revelation, first noted by state media, sent Chinese health inspectors into a snit as they scrambled to reassure the public that the claims were being investigated.

"He Dongping, a professor at the Wuhan Polytechnic University, has been studying the problem for seven years," newspaper Epoch Times noted. "According to China Youth Daily, he found that China recycles an estimated two million to three million tons of waste oil per year. Combining that figure with the estimated 22.5 million tons of total vegetable oil and animal fat consumed by the Chinese per year, it is estimated that 10 percent is returning to people’s dining tables."

The only apparent difference between the toxic sewage oil and normal oil is the remarkable price difference, with the tainted cooking stock selling for approximately half the price of its legitimate competitor.

"In addition to an effective method of detection having yet to be found, the difficulty is compounded once the illegal oil has been blended into ordinary ones," state media China Daily reported. The 'illegal cooking oil' is usually made from discarded kitchen waste that has been refined [after being sieved out of raw sewage]. Although it looks clean and clear, it actually contains toxic substances, including 'aflatoxin', which can cause cancer."

"Aflatoxins are toxic metabolites produced by certain fungi in/on foods and feeds," according to Cornell University. "They are probably the best known and most intensively researched mycotoxins in the world. Aflatoxins have been associated with various diseases, such as aflatoxicosis, in livestock, domestic animals and humans throughout the world. The occurence of aflatoxins is influenced by certain environmental factors; hence the extent of contamination will vary with geographic location, agricultural and agronomic practices, and the susceptibility of commodities to fungal invasion during preharvest, storage, and/or processing periods."

The state-run China Daily news agency encourages consumers to be suspicious, recommending that buyers "taste" the cancer-causing substance before making a purchase.

The International Agency for Research on Cancer has identified aflatoxin B1 has a confirmed carcinogen in humans.

China's State Food and Drug Administration has vowed to close down any eatery found using tainted cooking oil.

This most recent food safety scandal comes on the heels of a devastating episode in which hundreds of thousands of Chinese infants were poisoned in 2008 by the chemical melamine, which had been used as a spacing ingredient in baby formula.

China consumes over 22 million tons of cooking oil each year, according to the study.