Simpson Thacher & Bartlett has helped ChemChina in obtaining clearance from the Committee on Foreign Investment in the United States (CFIUS) on its $43 billion acquisition of Swiss agrochemical firm Syngenta.

CFIUS scrutinizes deals for national security implications. The ChemChina-Syngenta deal is said to be the largest foreign acquisition ever by a Chinese company, and the CFIUS clearance boosts chances that it will go through.

The Simpson Thatcher team working on the transaction included U.S.-based partners Peter Thomas, Alan Klein and Christopher May, and Beijing partner Shaolin Luo.

The decision removes significant uncertainty over the takeover of the world’s largest pesticides maker, posed by several lawmakers and groups representing farmers expressed fears over a Chinese state-owned company being in a positon to influence the U.S agriculture market. 

The major regulatory hurdle of the deal now moves to an antitrust review by the European Union, which the companies may seek to facilitate through divestitures, according to insiders.

In the past, CFIUS has emerged as a key concern for Chinese firms looking to acquire technologies. Earlier this year, Philips NV dropped a $2.8 billion deal to sell its Lumileds LED light bulb business, Fairchild Semiconductor International turned down a bid from China Resources Microelectronics and Hua Capital Managementin favor of an existing deal to be bought by Arizona-based ON Semiconductor Corp and Beijing-based Unisplendour Corp terminated a plan to buy a 15 percent stake in a disk drive maker for $3.78 billion following undisclosed concerns from CFIUS.