(Adds U.S. Embassy comment)
BOGOTA, May 15 (Reuters) - Colombia will suspend aerial fumigation of illegal coca plants in light of a number of studies linking the herbicide involved to cancer, a move that marks the end of a decades-long strategy in the country's fight against drug trafficking.
Spraying coca leaves, which are used to make cocaine, has been a key part of Colombia's efforts to curb production of some 300 tonnes of cocaine a year that make it one of the world's biggest producers of the drug.
For two decades, the Andean country has used the herbicide glyphosate to fumigate coca, with financial and technical help from the United States. The strategy also included spraying of poppies, used to make heroin.
"We've taken the decision by a majority of seven to one, to suspend the spraying of areas with glyphosate," health minister Alejandro Gaviria said, referring to a vote taken by the National Narcotics Council late on Thursday.
Various scientific reports, including one by the World Health Organization (WHO) in March, have suggested that the weed killer is likely carcinogenic to humans, Gaviria said.
Spraying will be halted after administrative formalities are completed, which could take several weeks, he added. More than 1.6 million hectares (3.9 million acres) of land in Colombia have been sprayed using the chemical.
Glyphosate is a key ingredient in the world's most widely used herbicide, Roundup, produced by Monsanto Co.
Monsanto officials have said the chemical has been proven safe for decades and the company has demanded a retraction from the WHO over its report linking the herbicide to cancer.
President Juan Manuel Santos called for an end to the fumigations last week, adding law enforcement should intensify its efforts against other parts of the drug trafficking supply chain, which include clandestine laboratories and smuggling networks.
The U.S. will continue to coordinate with Colombian authorities on other drug eradication efforts if aerial fumigation is no longer possible, Kevin Whitaker, the U.S. ambassador to Colombia, has said.
Local communities have expressed concerns that exposure to glyphosate has caused illnesses, among them cancers and birth defects. Colombia was the only South American country still using the chemical, Colombian authorities said.
The defense ministry and other entities which fight narcotics trafficking will be tasked with recommending other ways to eradicate illegal plants, Gaviria added.
Opposition politicians have expressed concern that a halt to spraying may increase cocaine production. Leftist rebel groups, the FARC and ELN, as well as criminal gangs, make huge sums from their involvement in cocaine production and trafficking. (Reporting by Luis Jaime Acosta; Writing by Julia Symmes Cobb; Editing by Peter Murphy and Andrew Hay)