A controversy over cooking oil in China has prompted locals to take matters into their own hands as they strive to procure alternative supplies amid worries over the safety of edible oils available in the market.

They are turning to making their own oil by buying household oil press machines. According to local reports, sales of these machines in the past two weeks have exceeded sales over the six-month period.

Search volumes for oil press machines jumped 22 folds, and sales volumes rose 4 times between July 5 and July 12, compared to sales before the scandal broke, local media reported, citing data from online retailer JD.com.

“It’s not even opened yet, should I eat it or not?” a post on social media platform Xiaohongshu, captioning a video of a bottle of cooking oil, showcased locals’ worries. “It’s a shame to throw it away, but I’m afraid of going to the hospital and spending all my money if I eat it,” the user, based in China’s Guangxi province, added. Certain hashtags discussing the scandal also appear to have been censored on some platforms.

China’s authorities have launched an investigation into food safety concerns after domestic media revealed that a major state-owned company, Sinograin, had been using tankers that carry fuel to transport cooking oil.

These containers were not cleaned between the loads, according to Chinese Communist Party-owned Beijing News. Private conglomerate Hopefull Grain and Oil Group was also named in the report.

Other truckers interviewed for the report noted that in a bid to save costs, oftentimes these tankers are not cleaned before transporting edible liquids like cooking oil, soybean oil and syrup in China. Some edible oil manufacturers also do not strictly check or enforce whether or not the tanks are clean, Beijing News reported. 

It is an “open secret” in the tanker transportation industry that food and chemical liquids are transported interchangeably without sterilization or cleaning, one tanker driver reportedly said.

“What that means is [the] Chinese are going to be scared of dining out. They don’t want to eat in restaurants,” said Shaun Rein, founder of the China Market Research Group. He surmises that Chinese consumers are also going to start buying more imported oil, drawing comparison to the ripple effects of the 2008 melamine scandal. 

In 2008, China was rocked by one of its worst food safety scandals when melamine, a chemical used in plastic, was added to milk which poisoned 300,000 children and caused the deaths of six children. 

“The Chinese started going to Australia, started [going] to Europe to buy baby formula. I think the same thing is going to happen with cooking oil. Be careful of ‘Made in China’ food products,” Rein told CNBC’s “Squawk Box Europe.” 

Times Finance, which also reported about a surge in oil press sales, cited a local saying he intends to go to Hong Kong to buy cooking oil and other condiments, and cook more as he is not sure about the oil used in takeout dishes. 

The Chinese authorities have promised strict actions against the culprits. “Illegal enterprises and relevant responsible persons will be severely punished in accordance with the law and will not be tolerated,” China’s Commission on Food Safety of the State Council said.