The U.S. FDA published a warning letter citing persistent and unresolved problems at the Hebei Yuxing Bio-Engineering Co. facility in Hebei, China.
A 2015 FDA inspection of the facility documented 67 deviations regarding microbiological contamination occuring between January and August 2015, but the investigation determined that contamination has been ongoing since 2013.
The FDA has found Hebei Yuxing's response letter to be inadequate, stating that the API firm has "not definitively identified the specific root causes(s) of microbiological contamination problems, nor taken appropriate corrective actions and preventive actions."
According to the company's website, they are a "professional manufacturer for Vitamin B12," exported to over 50 countries.
The FDA placed the firm on Import Alert 66-40 on July 8, 2016.
Read the warning letter here