DEERFIELD, Ill., Feb. 21 (UPI) -- Baxter Chief Executive Officer Robert Parkinson said he was unaware the Food and Drug Administration had not inspected a suspect supplier in China.

Baxter International Inc. (NYSE:AX) has a contract with Scientific Protein Laboratories of Waunakee, Wis., the Chicago Tribune reported Thursday. But, the company had no direct financial ties to the drug company in Changzhou, China, where the active ingredient for its troubled version of heparin was produced, the paper reported.

"It's not unusual for us not to know that the FDA hasn't inspected a supplier to a supplier," Parkinson said.

Baxter's line of heparin, a blood-thinner, has been implicated in 350 allergic reactions since Jan. 1 and has been linked to 4 deaths.

Baxter has stopped production of the drug. But the company and the FDA's process of inspecting foreign concerns have both come under close scrutiny.

Chinese products, involved in a number of recalls for lead paint and tainted pet food last year, have also come under fire.

"The best way to ensure the highest quality of raw material is to have feet on the ground in China," said Dr. Patrick Soon-Shiong, chief executive officer of American Pharmaceutical Products, Inc., a rival producer of heparin.