Pigs as muscular, lean, fat-burning machines produce much better protein when given clenbuterol, but how safe is it to consume their meat, ask Chinese food safety officials?

Remember the Chinese melamine scandal? Well, another scandal has been brewing and this time it’s in Chinese pork. According to a report from the China Daily, 19 pigs among 689 waiting to be slaughtered and processed at a facility in China’s Henan province tested positive for clenbuterol. The substance can speed up the growth of muscles and burn fat, resulting in leaner pork, but is hazardous to humans.

Clenbuterol is banned as an additive in pig feed in China because humans can “suffer from nausea, headaches, limb tremors and even cancer after eating food containing the additive,” says the report. The additive was found in the urine of the 19 pigs tested by the local Jiyuan city government. The local authorities are investigating more than 1,300 hog farms and 130 feed suppliers, according to a statement from the Jiyuan government.

According to the report, none of the tainted meat has entered the Chinese market, but some consumers are not buying pork products because their confidence has been shaken. Any meat products suspected of being contaminated with the additive have been removed from retail shelves. All feedstuff and meat confirmed to contain the additive have been destroyed. In China, clenbuterol is known as “lean meat power.”

In NanjingCity, capital of Jiangsu province, the local government suspended the operation of a slaughter house after pigs there were believed to have been brought in from Henan tested positive for clenbuterol, says the China Daily report.