BOGOTA, Colombia (AP) – New labeling on the world's most popular weed killer as a likely cause of cancer is raising more questions for an aerial spraying program in Colombia that underpins U.S.-financed efforts to wipe out cocaine crops.
The International Agency for Research on Cancer, a French-based research arm of the World Health Organization, on Thursday reclassified the herbicide glyphosate as a carcinogen that poses a greater potential danger to industrial users than homeowners. The agency cited what it called convincing evidence that the herbicide produces cancer in lab animals and more limited findings that it causes non-Hodgkin's lymphoma in humans.
The glyphosate-based herbicide Roundup is a mainstay of industrial agriculture worldwide, and it's a preferred weapon for killing Colombian cocaine harvests. More than 4 million acres of land have been sprayed over the past two decades to kill coca plants, whose leaves produce cocaine.
The fumigation program, which is partly carried out by American contractors, long has provoked hostility from Colombia's left, which likens it to the U.S. military's use of the Agent Orange herbicide during the Vietnam War. Leftist rebels, currently in negotiations with the government to end a half-century conflict, are demanding an end to the spraying as part of any deal.
Daniel Mejia, a Bogota-based economist who is chairman of an expert panel advising the Colombian government on its drug strategy, said the report is by far the most authoritative and could end up burying the fumigation program.
"Nobody can accuse the WHO of being ideologically biased," Mejia said, noting that questions already had been raised about the effectiveness of the spraying strategy and its potential health risks.
Mejia's own research published last year found higher rates of skin problems and miscarriages in districts targeted by herbicides. It was based on a study of medical records from 2003 to 2007.
Colombia's ombudsman office said it would seek suspension of the spraying program if the WHO results prove convincing.
But U.S. and Colombian government officials argue that cocaine does more health damage than aerial spraying.
"Without a doubt this reopens the debate on fumigation and causes us to worry," Colombia Health Minister Alejandro Gaviria told The Associated Press on Saturday, referring to the WHO findings.
But Gaviria argued that the need to suppress cocaine harvests "transcends" other considerations.
Monsanto and other manufacturers of glyphosate-based products strongly rejected the WHO ruling. They cited a 2012 ruling by the U.S. Environmental Protection Agency that the herbicide was safe.
Colombia already has scaled back use of aerial herbicides in favor of more labor-intensive manual eradication efforts, partly in response to criticism by farmers.
Colombian officials say aerial spraying last year covered 55,000 hectares (136,000 acres), down from a 2006 peak of 172,000 hectares (425,000 acres).
Critics of the program concede that the government has improved safety standards, such as by avoiding herbicide flights during strong winds, and installing GPS devices on fumigation aircraft that keep records of plane movements and help investigators to determine the validity of farmers' compensation claims.
In 2013, Colombia agreed to pay Ecuador $15 million to settle a lawsuit over economic and human damage linked to spraying along their common border.
Gen. Ricardo Restrepo, commander of the anti-narcotics police, said he had not seen the WHO warning, and Colombia's herbicide spraying was proceeding as usual.
"My job is to carry out the strategy," he said.