China's General Administration of Quality Supervision, Inspection & Quarantine has closed two plants that supplied substandard pet food ingredients to the U.S. It also closed a plant that produced diethylene glycol that was later mislabeled as glycerin and used to make a cough syrup that killed dozens of people in Panama last year. Earlier this year, Chinese investigators found that the marketing practices of Jiangsu-based Taixing Glycerin were questionable because the company sold some diethylene glycol under the trade name TD Glycerin (C&EN, June 18, page 40). But at the time, the regulators also said that the Chinese firm had clearly told its Panamanian buyer what the product contained. The government did not say why it decided to shut Taixing. As for the two producers of pet food ingredients, the administration found that they had evaded compulsory inspections of an ingredient exported to the U.S. by misrepresenting it as a chemical not meant to be consumed. The ingredient contained melamine that was added to boost protein content readings.