"I have used Kausha to cure onions," Paul Lankoi* said on the phone as my investigations towards making this report began
It was a brave admission; considering that it could as well be an admission to a crime.
"I am not the only one who cures onions this way: I think generally farmers [around here] do it like that," he continued.
Our team took the journey to Kimana, in Oloitoktok - to visit Lankoi's farm. The route is teeming with onion sales at roadsides; evidence of a thriving onion-growing industry.
Talking to our sources in Oloitoktok we were fairly convinced that the practice is common among onion farmers in the area.
Kausha is a herbicide whose chief ingredient is glyphosate. We could not ascertain the origin of its name though in Swahili it means 'Dry it'.
The pesticide - like many glyphosate-based herbicides - is used to kill weeds
Smart Harvest received a hunch on the practice of curing onions using glyphosate pesticides from a concerned farmer.
"It happens a lot in Oloitoktok," she said, provided we protected her identity.
As we investigated, we interviewed Jessica Syombua, from Emali, who farms onions on three acres.
"I don't know much about the use of glyphosate to cure onions," she told us.
Our line of questioning however provoked thoughts on whether her farm manager - the man who is in charge of the enterprise - has ever done it.
"I have noticed that just a week before harvesting, or thereabouts, he asks me to buy some pesticides. Usually, this happens when the weather is cold or wet. I don't know if he dries the onions using the pesticides," she says.
When onions are ready for harvest, notes Noah Nasiali, it beats logic to apply pesticides. Chances are high, therefore, that Syombua's farm manager used glyphosate to cure the onions.
When bulb onions are ready for harvesting they are cured over a period of time that could last a month.
In about a week, the farmer can wait another week and then harvest by pulling the crop out.
Bulbs are then cut from any stems that won't have detached already and then moved to a shaded protected area and spread out in a single layer over a floor covered with sacs or dry linen or even raised wooden floor.
"The onions can stay there as drying continues for anything between a week and four weeks depending on weather conditions," Nasiali says.
Properly cured onions have a long shelf life: some can remain fresh for a year while still in the store.
Those using glyphosate herbicides to cure onions, Nasiali suspects, are "without a doubt using shortcuts so that they can take their produce to the market and hopefully make a kill."
On spraying, glyphosate is absorbed through leaves of a plant. The chemical works by interfering with enzymatic processes that arrests the plant's photosynthesis and thereby starving it to death, says Dr. Isaac Omwenga, a Board certified and European registered toxicologist.
Other experts add that the chemical moves to the roots of the plant and block uptake of water; desiccating the plant quickly.
The problem with using glyphosate to cure onions is that the crop ends up with unhealthy residue-levels that would easily make it to plates.
In 2015, the International Agency for Research on Cancer (IARC) released a report which concluded that glyphosate is 'probably carcinogenic to humans.'
IARC, an agency of World Health Organization (WHO), subsequently classified glyphosate as class 2(a) 'possible carcinogen'.
This conclusion was also supported by a University of Washington meta-study that found that the overall meta-relative risk of non-Hodgkin lymphoma (NHL) in individuals exposed to glyphosate-based herbicides increased by 41 per cent.
The world's poster child for how glyphosate is carcinogenic is an American from San Francisco, California, called Dewayne Johnson.
Johnson, a former school groundskeeper, applied Round Up 20 to 30 times every year before being diagnosed with NHL in 2014.
Johnson sued Monsanto - the original manufacturer of Round Up - and in 2018 jurors ruled that the weed killer was responsible for the former school grounds-keeper's cancer.
In 2020, Bayer, upon acquiring Monsanto, moved to settle tens of thousands of cases involving the herbicide.
In Kenya, there are at least 70 pesticides containing glyphosate that have been licensed to be sold.
The Pesticide Atlas 2022 Kenyan Edition, published by Heinrich Boll Stifftung (HBS) Foundation, notes that glyphosate is classified as a highly harzadous pesticide (HHP) by Pesticides Action Network (PAN).
WHO and Food and Agricultural Organisation (FAO) have developed a code of conduct that recommends avoiding of HHPs or pesticides that require personal protective equipment (PPE).
The Agrochemical Association of Kenya (AAK), through their website, have explained their position on use glyphosate by farmers.
'On the basis of current scientific evidence, glyphosate-based products pose no undue health risks, including cancer, to the Kenyan public.
'AAK advocates for use of personal protective Equipment when using any pesticide, as guided by the Pest Control Products labelling guidelines.
'These efforts are geared towards protecting communities and the environment against potential hazards of chemicals,' reads part of statement.
Dr. Esther Kimani, the CEO of Pest Control Products Board (PCPB), says while the board has licensed glyphosate products to be used in farming in Kenya, all farmers and farm workers should follow guidelines on application.
"All pesticides are chemicals that are toxic to human beings. That is why they are regulated," she says.
Dr. Omwenga points out that commercial food production requires that farmers use pesticides like glyphosate for maximum yield.
"The problem is usage: are you applying the right dosage, for the right crop, at the right time, for the right reason?"he asks.
In June 2022, AAK and PCPB released findings from a baseline study on pesticides residues in kales, tomatoes and onions in Kajiado, Nakuru and Nyandarua Counties.
The researchers established that no sample had glyphosate residue levels above European Union (EU) Standards.
The pesticide Atlas refers to a 2020 survey in which 25 different active ingredients were found in tomato and kale samples in Kenya. About 60 per cent of the samples exceeded the EU maximum.
In Kenya, Biodiversity and Biosafety Association of Kenya (BIBA-K), Kenya Organic Agriculture Network (KOAN), Resource Oriented Development Initiatives (RODI Kenya) and Route to Food Initiative (RTFI) wrote and submitted Public petition number 70 of 2019 to the National Assembly, calling for withdrawal of all toxic pesticides - glyphosate being a prominent one - from use in the country.