The Verdict: Why Conventional Potatoes Are on the Dirty Dozen
For many years, some consumers debated whether potatoes belonged on the Clean 15 or Dirty Dozen list, but recent assessments by the Environmental Working Group (EWG) have clarified their status. In its 2025 Shopper's Guide, the EWG officially included conventional potatoes on its 'Dirty Dozen' list of produce with the highest pesticide contamination.
This placement was primarily driven by the high prevalence of the post-harvest chemical chlorpropham. USDA testing revealed that nearly 90% of conventional potato samples contained residues of this sprout inhibitor, which is applied after harvest to extend the potato's shelf life. Chlorpropham is of particular concern because the European Union ended its approval in 2019 due to consumer and worker health risks identified in a 2017 assessment. Further analysis has identified other health concerns related to its breakdown product, 3-chloroaniline, which may form in fried potatoes and raises carcinogenic concerns. The EWG's updated methodology, which accounts for the toxicity of pesticides, moved conventional potatoes onto the list, alongside other high-residue items like strawberries and spinach.
How the Lists are Compiled
The EWG's annual guide is based on data from the U.S. Department of Agriculture (USDA). The USDA tests a variety of popular fruits and vegetables, and critically, these samples are prepared as they would be at home—washed, scrubbed, or peeled. The fact that significant pesticide residues, including chlorpropham, persist on potatoes even after this process was a key factor in their ranking.
Contrasting Conventional and Organic Potatoes
For consumers concerned about pesticide exposure, the choice between conventional and organic potatoes is a primary consideration. The following comparison table highlights the key differences, particularly in the context of the EWG's findings.
| Feature | Conventional Potatoes | Organic Potatoes |
|---|---|---|
| Pesticide Use | Growers can use synthetic pesticides, including herbicides, insecticides, and post-harvest sprout inhibitors like chlorpropham. | Synthetic pesticides and fertilizers are prohibited. Growers use natural pest control and crop rotation methods. |
| Pesticide Residue | High residue levels, with over 90% of samples in recent USDA tests containing chlorpropham. | Significantly lower residue levels. Some cross-contamination may occur during storage, but levels are far below conventional. |
| Chlorpropham Status | Commonly treated with chlorpropham to prevent sprouting during storage. | Chlorpropham use is not permitted. Traces on organic potatoes are due to cross-contamination. |
| EU Status | Contaminated with a chemical (chlorpropham) banned for use in the European Union since 2019. | Contains minimal or no residue of chlorpropham. |
| Nutritional Content | Rich in vitamins and minerals like potassium, vitamin C, and vitamin B6. | Generally considered to retain more of their natural nutrients due to soil health practices. |
| Cost | Typically less expensive due to higher yields and lower production costs. | More expensive, reflecting different farming practices and certification costs. |
How to Reduce Your Exposure to Pesticides
For those who prefer not to switch exclusively to organic potatoes, or who are on a budget, there are still several effective methods to reduce pesticide exposure. Eating plenty of fruits and vegetables, whether conventional or organic, remains beneficial for health, and simple preparation steps can significantly reduce residue levels.
- Wash thoroughly: Scrub potatoes under cold, running water with a stiff vegetable brush. This helps dislodge soil and surface-level contaminants.
- Consider peeling: Since many pesticides, like chlorpropham, are primarily applied post-harvest to the skin, peeling conventional potatoes can drastically reduce exposure. Note that peeling also removes some of the skin's nutrients and fiber.
- Use a vinegar soak: For unpeeled potatoes, soak them for 5 to 10 minutes in a solution of one part white vinegar to three parts water before scrubbing. This can help break down some residues.
- Opt for sweet potatoes: Unlike white potatoes, non-organic sweet potatoes are not treated with chlorpropham and are considered a cleaner alternative by the EWG.
- Balance your shopping: Use the Dirty Dozen and Clean Fifteen lists as a guide. Prioritize organic purchases for items on the Dirty Dozen, and feel more confident buying conventional produce from the Clean 15 list.
The Verdict on Sweet Potatoes
It is important to distinguish between white potatoes and sweet potatoes. While white potatoes were placed on the Dirty Dozen, sweet potatoes maintain a much cleaner profile and were only two spots away from the Clean Fifteen list in a recent EWG analysis. This is because conventional sweet potatoes are not typically sprayed with chlorpropham. Therefore, if minimizing pesticide exposure is your main concern, non-organic sweet potatoes are a much safer alternative to conventional white potatoes.
Conclusion
The inclusion of conventional potatoes on the EWG's Dirty Dozen list in 2025 is a result of updated data and methodology that considers the toxicity of detected pesticides, particularly chlorpropham. While the presence of pesticides raises valid consumer concerns, it is not a reason to stop eating this nutrient-dense vegetable. Instead, this information serves as a useful guide for making informed purchasing decisions. For those seeking to minimize pesticide exposure, buying organic potatoes or choosing cleaner alternatives like sweet potatoes is the best path. For others, proper washing and peeling of conventional potatoes can be an effective compromise.
The Nutritional Value of Potatoes
Despite the pesticide concerns with conventional varieties, potatoes remain a staple and nutritious part of many diets. They are naturally gluten-free and packed with essential nutrients, including potassium, vitamin C, and fiber. For those with dietary restrictions or specific health goals, potatoes offer significant benefits. Resistant starch found in potatoes can also improve blood sugar control and digestive health.
For more detailed information on chlorpropham and other agricultural chemicals, consider exploring the resources at Beyond Pesticides, a respected authority on the subject. Beyond Pesticides
