The chemical compound oversulfated chondroitin sulfate is the contaminant in batches of heparin that has been linked to 19 deaths and several hundred serious health problems in the United States, according to information presented by the Food and Drug Administration in a press conference on March 19.

"At the moment we don't know definitively whether the contaminant was introduced intentionally or by accident," said Dr. Janet Woodcock, director of the FDA's Center for Drug Evaluation and Research.

Now that the heparinlike contaminant has been identified, the FDA intends to move forward to determine how and when it was introduced into the supply chain. The contaminant ...