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by Erika Shinpaugh
When it comes to dish soap, it seems like simpler is the way to go. Natural oils (when processed the right way, often using traditional methods) provide cleaning effective enough for most users. Dish soaps can be DIY-ed using castile soap, a sustainable all-purpose cleaner that is easy to come across. Some users find they need to add nothing else besides water for castile soap to work, but other users add a few more ingredients. For those erring on the side of caution, sustainable pre-made multipurpose soaps and dish soaps may be the way to go. We recommend choosing a solid, concentrated product for 3 reasons: it saves a lot of water and transport emissions, allows for compostable packaging options, and provides more opportunities to skip toxic ingredients like preservatives. Sorting through labels can be difficult though, as terms such as “non-toxic”, “natural”, and “made-from-plants’’ are unregulated, so we recommend checking ingredient lists on all dish soaps. Often the simpler the safer, and sites such as EWG ratings can be used as a starting point for understanding personal and environmental health risks of particular ingredients. The largest, in-store dish soap brands are often petroleum-based and toxic, with even “green” brands sharing some of these attributes. These products are usually liquid, and therefore also come in a plastic bottle. However, these liquid dish soaps usually work as detergents rather than soaps, which can give them a leg up on cutting grease. If this becomes relevant to you while trying the other recommended options, it might be a good idea to supplement your kitchen with a single bottle of liquid dish soap to use just every once in a while, but we recommend checking for EWG rating information or EPA Safer Choice Certification on options if doing so. A final tid-bit of knowledge is that research has found that the most sustainable way of doing dishes can be by hand, but only if the “two-basin” method is used in which plates are first soaked in warm, soapy water before being dunked in cool, clean water. As such, if you’re looking to wash a whole sink full of dishes we recommend trying this method first, although it might need to be tweaked based on dish soap type.
As mentioned, for dish soaps it seems that smaller brands are often the better choice. For that reason, the best products may not have these certifications. Instead look to these third party endorsements primarily to make sense of products with long or confusing ingredient lists.
EWG rating/ “EWG verified” - So far, very few brands have worked directly with EWG to receive the certification of “EWG verified.” However, EWG itself has reviewed products from many larger brands in the same areas of interest as the certification, including transparency, human health concerns, and environmental health concerns. While these ratings won’t be found on the bottle they can be easily looked up online, although we recommend using this resource in combination with others for a more complete understanding of risk.
EPA Safer Choice - This certification does not necessarily mean that a product doesn’t cause harm to human health or the environment, rather its focus is on whether the ingredients are the “lowest hazard in their functional class.” For example, dish soaps you can often buy in stores are actually detergents, made with a functional class of ingredients called surfactants. Surfactants often pose environmental and health risks, and through this program the EPA evaluates which kinds of surfactants pose the least risks. They then allow these in EPA Safer Choice verified products. What they don’t consider is removing surfactants and replacing them with ingredients in a different functional class, which could potentially eliminate the risks.
USDA Biobased Product - This certification means a product is “composed, in whole or in significant part, of biological products.” This means that a product with this certification uses a number of ingredients that are not petroleum based, but doesn’t guarantee that all are not. Additionally, this certification does not speak to environmental or health concerns.
These are terms that can show up on sustainable and greenwashed products alike. Back up claims by reading the ingredient list (and if there is no ingredient list, claims are likely not supportable).
“Made From Plants” - This term may mean that plant-based detergents are used instead petroleum-based ones, which is environmentally preferable. However, because this term is unregulated this may not always be the case, and this label does not necessarily mean that all ingredients are made from plants.
“Natural, Chemical Free” - similar to “Made From Plants”
“Non-Toxic” - Used very loosely by dish soap brands, this term is meaningless without backing up by checking the toxicity of ingredient lists.
“Biodegradable” - Also used very loosely by different brands, does not necessarily mean the product is 100% biodegradable.
Ingredients to avoid:
These are common terms and ingredients that we recommend aiming to avoid for your health or that of the environment. This list is definitely not all inclusive, but these are some of the worst or most common.
Methylisothiazolinone - Preservative that is toxic. Many “green” brands still contain this among other chemicals.
Sodium Laureth Sulfate (SLES) - Surfactant which often has 1 4-dioxane as a byproduct, which is a known carcinogen that can also pose other risks to health and aquatic wildlife.
Sodium Lauryl Sulfate (SLS) - Surfactant often used in dish soaps. Research on two early “green” dish soaps found that SLS accounted for most of the lifecycle impact of these products. Avoid when possible.
Fragrance (including Phthalates) - Often synthetic substances which cause a range of problems such as acute aquatic toxicity, respiratory effects, and incomplete biodegradation. Phthalates specifically have been linked to endocrine disruption, birth defects, and developmental delays.
Antibacterials - The FDA notes that no benefits have been shown in antibacterial soaps over soaps without, and antibacterial soaps could increase bacterial resistance in waterways.
Environmental Working Group (EWG) - https://www.ewg.org/guides/subcategories/25-HandWashingDetergent/ - You can look up specific dish soaps in this database or ingredients by themselves in several of their databases. (Disclaimer: EWG rankings should be taken with a grain of salt as there are limitations on the scope and applicability of the data. Ingredients may not cause harm at doses found in products, however the resources do provide clarity in linking ingredients found in products to research studies done on them.)
Ethical Consumer’s dish soap analysis: https://www.ethicalconsumer.org/home-garden/shopping-guide/ethical-washing-up-liquid
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