Potatoes Join the Dirty Dozen: What Led to the Change?
While some previously thought peeling potatoes minimized pesticide risk, the Environmental Working Group (EWG) added potatoes to their annual Dirty Dozen list in 2025 based on USDA and FDA data. This list helps consumers identify produce with the most pesticide residue.
The main factor for this inclusion was the detection of chlorpropham, a post-harvest sprout inhibitor, in nearly 90% of potato samples tested. Applied after harvest, chlorpropham remains on the final product, and its porous nature means washing or peeling may not completely remove it. The EWG noted that the European Union banned this chemical in 2019 due to health concerns.
The Science Behind the Ranking
The EWG's ranking considers the percentage of samples with detectable pesticides, the number of different pesticides, and their concentration. Potatoes' high ranking stemmed from the widespread detection of chlorpropham, which heavily influenced their overall pesticide score.
Comparing Conventional and Organic Potatoes
Organic potatoes, grown without synthetic pesticides, do not receive the same post-harvest chemical treatment. Organic options are generally more expensive, and the EWG advises prioritizing organic versions of Dirty Dozen items when on a budget.
The Dirty Dozen vs. The Clean Fifteen: Potatoes vs. Sweet Potatoes
It's important to note the difference between white potatoes and sweet potatoes. While conventional white potatoes are on the Dirty Dozen, sweet potatoes are consistently on the Clean Fifteen, indicating much lower pesticide levels. This is partly due to their natural pest resistance.
| Feature | Conventional Potatoes (Dirty Dozen) | Sweet Potatoes (Clean Fifteen) |
|---|---|---|
| EWG Status (2025) | Dirty Dozen | Clean Fifteen |
| Primary Pesticide Concern | Chlorpropham (post-harvest sprout inhibitor) | Very low pesticide residue |
| Key Differentiator | Late-stage chemical application to prevent sprouting | Naturally more pest-resistant and fewer applied pesticides |
| Peeling Impact | Does not guarantee removal of all residues | Peeling is less critical for pesticide concerns |
| Shopping Recommendation | Buy organic when possible | Conventional is generally a safe choice |
Practical Tips for Reducing Pesticide Exposure
For conventional potatoes, washing and scrubbing can help remove surface residues, though it won't eliminate all risk. Peeling can also reduce exposure but removes some nutrients in the skin. The most effective method to avoid pesticide residue is choosing organic potatoes.
Making an Informed Decision
The choice between organic and conventional potatoes depends on your budget and priorities. The EWG's list is a tool to empower informed decisions. Understanding why potatoes are on the Dirty Dozen helps you choose, whether that's organic for lower exposure or conventional with careful washing. Maintaining a diet rich in fruits and vegetables is crucial.
Conclusion
In 2025, potatoes were added to the EWG's Dirty Dozen list primarily due to the widespread presence of the post-harvest chemical chlorpropham. Health concerns around this chemical, banned in the EU, were a key factor. While washing and peeling conventional potatoes offers some help, organic options or choosing alternatives like sweet potatoes are most effective for minimizing exposure. The Dirty Dozen list serves as a guide for making informed produce choices.
