The news that a tenth of all cooking oil used in China may be made from recycled sewage and laced with toxic contaminants has stunned China.

Originating from a report on a state radio station, the news that Chinese are eating 3,000,000 tons of recycled cooking oil each year, but it is 100 times more toxic than arsenic! spread throughout China in a matter of days.

The cooking oil is apparently recycled from raw sewage taken from sewers and elsewhere, which is heated and filtered. After filtration the liquid is transparent and free of particulate matter, and can be rendered into cooking oil.

Fears over the toxicity of the recycled oil are high. Significant levels of aflatoxins have been detected, a poison said to be 100 times more toxic than arsenic, and known to cause growth defects in children and cancer.

Viral and bacterial contaminants are thought not to be a problem, assuming the sewage-oil is properly boiled in preparation.

Despite the obvious hygiene and safety problems of using treated sewage in cooking, its usage is thought to be widespread, as the recycled cooking oil is all but indistinguishable from normal cooking oil, in all but one aspect its price.

It costs only 300 yuan ($45) a ton to manufacture, half the price of regular oil, and it is said to be common use throughout China estimates are that it constitutes a tenth of all cooking oil used in China.

Chinese food safety regulators, such as they are, launched an immediate emergency investigation, although it is not clear if they actually previously approved the activity.

Chinas record on food safety is of course already utterly abysmal, but if as widespread as reported this could turn out to be the most damaging scandal to date, as cooking oil is an integral part of food preparation in China.

Nations importing cheap cooked foodstuffs from China may also be concerned that they have been inadvertently poisoning their children by trading with a nation in which regulation and business ethics are all but unknown.