Bogota, May 11 (teleSUR-RHC)-- Colombian President Juan Manuel Santos has announced that he is halting the use of an herbicide known as Glyphosate on coca crops, marking a significant blow to a U.S.-financed program aimed at halting cocaine production.

"I am going to ask the government officials in the National Drug Council at their next meeting to suspend glyphosate spraying of illicit cultivations (of coca)," Santos said.

Santos decision comes after the World Health Organization reclassified the herbicide as a carcinogen. In its report it observed that the herbicide produces cancer in lab animals and more limited findings that it causes non-Hodgkin's lymphoma in humans.

According to the Washington Office on Latin America, approximately 4 million acres of land in Colombia were sprayed with herbicide between 1996 and 2012 to kill coca plants, whose leaves are also used to produce cocaine.

The aerial spraying was a main component of the U.S.-financed Plan Colombia, which also included billions in military aid used by Colombia's government for counter-insurgency efforts. As early as 2007, the effectiveness of crop spraying was called into question following the publication of a White House-sponsored report concluding that the policy of aerial spraying had failed to reduce production levels, with land area under coca cultivation increasing by 9 percent, despite a 24 percent increase in spraying.