Baxter International's recalled blood-thinner heparin appears to have been intentionally contaminated with a similar, but cheaper, chemical, the company's top executive told a congressional panel last week. "We're alarmed that one of our products was used in what appears to have been a deliberate scheme to adulterate a life-saving medication and that people have suffered as a result," Baxter Chairman Robert L. Parkinson Jr. said in testimony before the House Energy & Commerce Subcommittee on Oversight & Investigations. "We deeply regret that this has happened, and I feel a strong sense of personal responsibility for these circumstances," he remarked. Baxter, which supplied about half the U.S. heparin market, began recalling the drug in January. David G. Strunce, chief executive of Scientific Protein Laboratories (SPL), also said the contamination appeared deliberate. SPL owns a majority stake in the Chinese plant that makes the active ingredient used in Baxter's heparin. Rep. Bart Stupak (D-Mich.), subcommittee chairman, said, however, it is unclear whether contamination with the cheaper chemical was intentional or accidental. But he stressed that both companies had a responsibility to ensure that their products were safe. "Baxter and SPL have failed the American public," he said. FDA has identified the contaminant as oversulfated chondroitin sulfate (C&EN, March 24, page 13).