WASHINGTON – Members of the House Energy and Commerce Committee are raising concerns about the potential impact of the proposed acquisition of the company by Shuanghui International Holdings, Ltd. on the domestic supply of heparin.

The committee's concerns come during an ongoing investigation into heparin contamination. The investigation dates back to 2008. Heparin is a blood thinner that is used to treat blood, heart and lung disorders. Smithfield Foods is a major supplier of crude heparin, which is made from pig intestines.

In a letterto Larry Pope, CEO of Smithfield Foods Inc., the committee members said the Food and Drug Administration and other authorities have linked contamination of the US heparin supply to "intentional adulteration during the manufacture of heparin in China..." The committee wrote: "The committee’s investigation indicates that the US heparin supply is stressed, and could well be in shortage. China’s heparin market is experiencing its own pressures, and Smithfield Foods under Shuanghui control may be pressured to export its crude heparin product to China instead of supplying US companies. The impact of this pending acquisition on the availability of US heparin is critical. Heparin is still widely used for heart surgery and dialysis patients."

The committee also said it was troubled by Shuanghui International's link to a clenbuterol poisoning scandal in China. Clenbuterol is used as a decongestant and bronchodilator for asthma patients. The FDA banned use of the drug in food animals. The drug was found after 18 outbreaks of food-related clenbuterol poisoning occurred from 1998-2007. China's agriculture banned the use of clenbuterol in 1997.

"The fact that the business practices under Shuanghui International control led to such contamination heightens our concerns of how Smithfield Foods will be able to maintain the safety of its heparin products should distribution of crude heparin be maintained in the US,” the committee wrote.

The committee set a deadline of Aug. 7 for responses to the questions raised in the letter.