Baxter's injectable heparin, is a blood thinner which has been in use for decades in many countries but the problems have only arisen since the end of 2007.
Baxter has now halted sales of some versions of the drug.
The FDA says preparations are being made to perform an inspection as soon as possible while Baxter maintains it inspected the facility, which is owned by a U.S. based company, within the last six months and another inspection is planned soon.
Baxter, which makes about half of all multiple-dose vials of heparin sold in the United States, says that company has been making heparin for more than 30 years.
Baxter buys the active ingredient for the drug heparin, which is only one of the potential suspects, from a supplier that manufactures it at both the Chinese factory and a facility in the U.S.
Heparin is used mainly in hospital settings to prevent blood clots and is crucial in haemodialysis and heart surgery; millions of patients each year are given the product intravenously.
The FDA has advised doctors to stop using Baxter's heparin until investigations identify the source of the problem.
