Chinese officials are questioning whether a contaminant can be blamed for deadly allergic reactions in people who used the blood-thinner heparin.

The U.S. Food and Drug Administration has counted 62 deaths tied to recalled batches of heparin. The FDA can't yet say what caused the reactions, but the chief suspect has been a contaminant found in supplies of raw heparin coming from China.

Now Chinese officials suggest the problems with the drug might be traced to a U.S. facility. They plan to visit a Baxter International plant in New Jersey to see how the finished product is made.

The Chinese officials also note that more than 10 other countries used heparin containing the contaminant, but reported no side effects.

Health and Human Services Secretary Mike Leavitt says the FDA will respond to China's concerns.