Nearly 70 percent of fruits and vegetables sold in the US has pesticide residue on it even after being washed, a new report has found.
Strawberries, spinach and kale claimed the top three spots of the Environmental Working Group's (EWG) annual Dirty Dozen list, which ranks the most pesticide-heavy produce.
Avocados, sweet corn and pineapples were found to have the least amount of residue. Kale appeared on the list for the first time in nearly a decade after researchers found a staggeringly high 92 percent of samples of the leafy green had pesticide residue.
The last time that kale was tested, it was ninth out of 12 on the list.
The report also found that one sample of kale had evidence of as many as 18 separate pesticides.
Additionally, Dacthal - a pesticide that has been banned in Europe since 2009 and is classified as a possible carcinogen - was found on 60 percent of the samples.
'Kale had not been tested by the USDA so with this new data, when we looked at the metrics, we were surprised to see such a significant increase,' Dr Alexis Temkin, a toxicologist at the EWG who worked on the report, told DailyMail.com
Rounding out the top five on the Dirty Dozen list were nectarines and apples, both of which had more than 90 percent of samples confirmed to have at least one pesticide residue.
However, strawberries were the worst offenders, with almost all of the samples - 99 percent - found to have residue of at least one pesticide.
Additionally, around 30 percent of the samples had 10 or most pesticides on them.
Nneka Leiba, director of EWG's healthy living science program, said the results were disconcerting.
'One of the things we want to highlight is that the USDA and FDA can do better job at testing,' she told DailyMail.com.
'They can test more fruits and vegetables more often. There was a 10-year span that we didn't realize the level of pesticides had shot up in kale and that was the thing people were eating.'
The EWG did state that despite the classification of 'dirty', all of the pesticides found on produce fell within the legal limits set by the Environmental Protection Agency.
Compiled alongside the Dirty Dozen list was the group's annual Clean Fifteen, which ranks the fruits and vegetables that have the least pesticide residue.
Making up the top five were avocados, sweet corn, pineapples, frozen sweet peas and onions.
The report found that less than one percent of avocado and sweet corn samples had any detectable pesticides.
In fact, on the Clean Fifteen list, a mere six percent of samples had residue of two or more pesticides.
