Costco has become a go-to store for families looking to stock up on everything from pantry staples to household products at budget-friendly prices. I’ve given Costco plenty of credit for offering safer and less toxic options than many mainstream stores, but not everything they sell is a win for your health or home. Just because it’s on the shelves at Costco doesn’t mean it’s free from harmful chemicals or safe for everyday use. When creating a non-toxic home, knowing which products to avoid is important—and why is important.

My Background in Environmental Science

Before diving into which products you should skip on your next Costco run, it might help to understand where I’m coming from. I started my career in environmental science decades ago, where I learned how toxins like synthetic chemicals and heavy metals affect the environment and our health. This experience gave me a unique perspective on how everyday products contribute to our toxic load over time. With this knowledge, I’ve prioritized avoiding certain products in my home and sharing these insights with others.

Products to Avoid at Costco (and Why)

Aluminum Foil and Parchment Paper

One of the first things to avoid is traditional aluminum foil and non-stick parchment paper. Aluminum is a known neurotoxin that can leach into your food, particularly when exposed to high heat.^[1] This isn’t just a minor concern—over time, elevated aluminum levels in the body have been linked to serious health issues, including neurodegenerative diseases that can affect cognitive function and overall quality of life. While aluminum exposure is often discussed regarding cookware, even wrapping your food in foil or using it to line baking sheets can increase your exposure. When you consider how we usually use aluminum foil daily, it becomes clear how easy it is for small amounts of aluminum to accumulate in the body over time.

Non-stick parchment paper may seem like a better option, but it often comes with problems. Many brands, including those found at Costco, are coated with silicone, which can release siloxanes when heated. Siloxanes are chemicals associated with hormone disruption, liver problems, fertility issues, and even cancer. What’s more concerning is that these chemicals can start to release at relatively low temperatures—sometimes as low as 200°F—making them a hidden risk in many kitchens. For safer alternatives, look for unbleached parchment paper without a non-stick coating or switch to reusable silicone baking mats made with food-grade silicone.

Tuna: A Source of Hidden Heavy Metals

Another item I avoid at Costco is tuna. While tuna can be a convenient and protein-rich food, it often contains high levels of mercury—a heavy metal that poses significant health risks, especially when consumed regularly. Mercury exposure is particularly dangerous because it accumulates in the body over time and is challenging to detox. High mercury levels are linked to neurological damage, cognitive decline, and an increased risk of cardiovascular problems. If you enjoy tuna, choosing lower-mercury options and eating them sparingly is important. Brands like Safe Catch and varieties like Skipjack tuna are generally lower in mercury, but even these should not be a staple in your diet. Checking that your tuna brand tests for heavy metals can add a layer of safety, ensuring you and your family avoid unnecessary exposure to this dangerous toxin.^[2]

Plug-In Fragrances: The Invisible Pollutant

The most concerning product on my “avoid” list is plug-in fragrances. These products promise to keep your home smelling fresh, but they do so by filling your indoor air with a cocktail of synthetic chemicals. Many of these chemicals, such as phthalates and volatile organic compounds (VOCs), are known endocrine disruptors and can contribute to health issues ranging from hormone imbalances to more severe conditions like cancer and heart disease. Because these fragrances release chemicals continuously, they contribute to constant low-level exposure, which can build up over time and affect your health and indoor air quality.

Unlike food-related toxins, which you can manage through diet and detoxification, air pollutants are much harder to avoid, especially when they are present in your home environment. Instead of plug-in fragrances, consider natural alternatives like essential oil diffusers or simmering a pot of water with citrus peels and spices. These options not only smell great but also avoid the risks associated with synthetic air fresheners.

Better Alternatives for a Non-Toxic Home

While knowing which products to avoid is important, it’s equally valuable to know what you can use instead. For aluminum foil, consider switching to glass or stainless steel containers for food storage and use beeswax wraps as a reusable option for covering food. When it comes to baking, unbleached, non-stick-free parchment paper or silicone mats can provide a safe alternative to traditional options. For those who enjoy fish but want to avoid heavy metals, consider safer seafood options like wild-caught salmon or smaller fish like sardines, which tend to accumulate fewer toxins. And for keeping your home smelling fresh, natural air purifiers like beeswax candles, essential oils, and regular ventilation are much healthier choices than synthetic fragrances.

Final Thoughts: Stay Informed and Shop Smart

Costco offers plenty of great products, and many healthier choices can be found in their aisles. However, not every product meets the standards for a non-toxic home. Awareness of hidden toxins in everyday items can help you make smarter choices for your health and well-being. By avoiding problematic products like aluminum foil, non-stick parchment paper, mercury-laden tuna, and plug-in fragrances, you significantly reduce your toxic load and create a healthier environment. Remember that knowledge is power next time you head to Costco or any store. Share this information with others who may unknowingly bring these products into their homes, and continue to seek out safer, non-toxic alternatives. Your body—and your home—will thank you.

References:

1. Dordevic, Dani, et al. “Aluminum Contamination of Food during Culinary Preparation: Case Study with Aluminum Foil and Consumers’ Preferences.” Food Science & Nutrition, vol. 7, no. 10, Sept. 2019, pp. 3349–60.
2. Bernhoft, Robin A. “Mercury Toxicity and Treatment: A Review of the Literature.” Journal of Environmental and Public Health, vol. 2012, 2012, p. 460508.