The deal is the largest foreign acquistion by a Chinese company but has been questioned by some US senators including Debbie Stabenow, Chuck Grassley, Sherrod Brown and Joni Ernst because of potential effects on US national security and the American food system.
The senators have called for a review by The Committee on Foreign Investment in the United States (CFIUS) and suggests that both the USDA and the FDA be included in this review.
The letter goes on to state: "While this Committee has not reached any conclusions regarding the proposed purchase of Syngenta by ChemChina, we believe that any foreign acquisition of an important U.S. agricultural asset should be reviewed closely for potential risks to our food system."
ChemChina and Syngenta have agreed to the review, meaning it could be several months be any deal goes through.
The proposed buy-out means that Syngenta's flower seed division will no longer be sold off.