Colombia wants to resume spraying a toxic chemical to fight cocaine. Critics say it's too risky

Two AT- 802 planes fumigate coca fields in San Miguel, 400 miles south of Bogota, Colombia, on Dec. 11, 2006.

Bogota (CNN)Colombia wants to resume aerial spraying of a toxic chemical in remote rural areas to stop the growth of coca, the chief ingredient of cocaine -- despite stark health concerns.

The spraying typically uses glyphosate, a chemical that the World Health Organization has linked to cancer and classified as "probably carcinogenic to humans." Colombia's government claims it can be done safely -- but critics argue it's dangerous and ineffective.
In 2015, then-president Juan Manuel Santos halted the practice but his successor President Ivan Duque -- with prodding from US President Donald Trump -- is now pushing for a hearing before Colombia's environmental licenses authority, in order to obtain permission to restart the controversial practice.
    Duque's government says eradicating coca crops will limit trafficking and violence by drug gangs, which it has blamed for seven massacres in August that killed 36 people, including several children.
    Cocaine production is currently around an all-time high in Colombia. According to the latest UN drug report, based on 2017 figures, Colombia produces around 70% of the world's cocaine, and while the crop size has declined slightly, the output is actually growing because of better productivity.
    Cocaine "is the principal stream of revenues for the criminal groups that are behind these recent massacres," Colombia's Defense Minister Carlos Holmes Trujillo said on August 24.
    Suspending aerial fumigation had been a "serious mistake," he said.

    'A toxic fog'

    Aerial fumigation allowed authorities to target illegal coca crops in hard-to-reach and often dangerous corners of Colombia.
    The government has pledged that future aerial fumigations will not take place in protected areas and national parks, Rafael Guarin, President Duque's national security advisor, told CNN, and only function within the parameters set by the environmental license authority.
    A plane sprays coca fields in San Miguel, on Colombia's southern border with Ecuador on Dec. 15, 2006.
    Jose David Hernandez, a farmer in rural Antioquia, who grew coca until 2018, remembers the aerial fumigations in 2003 and 2004.
    The herbicide would fall on the field like a toxic fog and cause irritation so painful that workers' skins would start bleeding, he said.
    Tens of miles away from the closest hospital, farmers would try to heal the wounds with an artisanal ointment that would bleach the skin. To this day, Hernandez told CNN his arms and legs have whiter spots where he applied the ointment trying to heal his wounds.
    The scientific debate on the dangers of glyphosate is ongoing. While the WHO has linked glyphosate to cancer, the US Environmental Protection Agency "find that there are no risks of concern to human health when glyphosate is used in accordance with its current label."
    Monsanto, the US company that manufactures glyphosate, recommends that users wear personal protection equipment. But in Colombia, the herbicide is often sprayed over a vast amount of land often without warnings to the workers in the fields, including farmers tending to the coca plants or others cultivating legal crops nearby.
    Critics of aerial fumigations also say there are risks beyond the potential for cancer, including concerns