Another major food health safety scandal rocks China.

A recent report exposing the transportation of cooking oil in fuel tankers has ignited a furor in China.

A bombshell investigation published on July 2 by the state-run Beijing News found multiple cases of fuel tankers transporting edible cooking oil immediately after delivering chemicals used for coal-to-liquid processing. The expose’s author, Han Futao, found trucks were delivering chemicals and edible oil interchangeably without cleaning the tanks between loads.

Han described one case in which a tank truck in Hebei province delivered chemicals in Qinhuangdao before rushing to Sanhe days later to be filled with soy oil. The release of these findings has led to a significant public outcry, reigniting concerns about food safety in China.

The Business Insider reports:

The backlash ballooned even further when people began reposting regulatory warnings from 2013 about the practice in Hunan province, indicating its use for more than a decade. A 2005 local news report describing the mixing of edible oils with “hazardous chemicals” during transport went viral, too. “They’ve been caught before, but the problem persists. Is the punishment harsh enough?” one blogger wrote. “19 years ago, the media reported that the tanks were mixed with food. Why hasn’t it been solved yet?” another wrote.

Days after the Beijing News‘ report, state media jumped in with scathing commentary. “If this is an ‘open secret in the industry,’ where does it put the public’s health and life safety? Where does it put the dignity and justice of the law?” the People’s Daily columnist Zhang Jingshan wrote on Monday evening. Sinograin, a state body that oversees China’s grain and oil stocks, published a statement on Saturday saying it had launched an investigation into the “mixed use of tank trucks.” But the statement has been followed by calls online for a wider investigation involving higher authorities. “Checking your own unit is like covering your ears while stealing a bell,” wrote one blogger demanding an explanation.

Food safety in China has been a sensitive topic for years in the wake of multiple scandals involving gutter oil and deadly chemicals in baby milk powder. The repeated controversies have contributed to growing distrust in cities toward commercially sold foods in supermarkets and grocery stores, sparking a campaign by the central government to promote food safety.

In its analysis of China’s ongoing issues with food safety, the Observer Research Foundation (ORF), in India, cites a lack of monitoring and regulation by the government and a lack of ethics by food companies for profits, combined with environmental problems (such as soil pollution).