Toxic Costco Products I Personally Avoid (And What I Buy Instead)

Costco is genuinely great for a lot of things. But not everything on those warehouse shelves deserves a spot in your cart, especially if you’re trying to reduce your family’s daily chemical exposure.

Some of the most problematic items aren’t obscure. They’re popular, inexpensive, and easy to grab in bulk without a second thought. That’s exactly what makes them worth talking about.

Here are three categories I avoid at Costco, why they concern me, and what I choose instead.

Why Common Products Are Worth a Second Look

Many everyday products contain chemical additives, synthetic materials, or ingredients that have raised flags among researchers and environmental health advocates. The concern is the cumulative effect of using dozens of these products repeatedly, every day, over the years.

1. Plastic Flip-Flops

Flip-flops are a summer staple, and Costco carries them in bulk at unbeatable prices. But most cheap plastic sandals are made from PVC, EVA foam, or polyurethane: petroleum-derived materials that often contain additives to improve flexibility, texture, and durability.

The Concern: Phthalates.

Phthalates are plasticizers used to make materials softer and more flexible. They’ve been linked in research to potential hormone disruption, reproductive health effects, and developmental concerns, particularly for children. Some footwear products even carry warning labels about the presence of these chemicals.

Summer makes this worse. Feet sweat more, shoes sit in direct sunlight, and heat accelerates the breakdown of synthetic materials, all of which can increase the release of chemical compounds from the footwear.

What I choose instead:

• Natural rubber sandals
• Leather sandals from reputable manufacturers
• Cork-based footwear
• Going barefoot on grass, sand, or soil when practical

It’s one of the easiest swaps to make, and natural rubber or leather sandals often hold up far longer than cheap plastic ones anyway.

2. Conventional Chemical Sunscreen

Sun protection matters; excessive UV exposure increases the risk of sunburn, premature aging, and skin cancer.

Most conventional sunscreens use chemical UV filters that absorb ultraviolet radiation and convert it to heat before it penetrates the skin. One of the most common is octocrylene.

The Concern: Absorption And Hormone Signaling.

Research has shown that certain chemical UV filters, including octocrylene, can be absorbed through the skin and detected in the bloodstream after use. Regulatory agencies and researchers are actively studying the long-term health implications of this. Some studies have examined whether these ingredients may influence hormone signaling pathways, though the science is still developing.

The other issue is fragrance. “Fragrance” on an ingredient label can represent a blend of dozens or even hundreds of undisclosed chemicals. Some fragrance compounds are associated with skin irritation, allergic reactions, and potential effects in sensitive individuals, including kids.

What I choose instead: mineral sunscreen.

Mineral sunscreens use zinc oxide to create a physical barrier that reflects and scatters UV light rather than absorbing it. They typically contain fewer synthetic ingredients and avoid the chemical filters that have raised the most concern.

When shopping, look for products that:

• Use non-nano zinc oxide as the active ingredient
• Are fragrance-free
• Have short, transparent ingredient lists
• Offer broad-spectrum (UVA + UVB) protection

Badger is a widely available option that checks these boxes and is readily available at many natural retailers. Whatever brand you choose, the goal is consistent protection, just with a cleaner formula.

3. Synthetic Underwear

Underwear rarely comes up in conversations about toxic exposure. It probably should.

It’s the clothing item with the longest daily skin contact, worn against some of the body’s most absorptive areas. Yet most mainstream options, including bulk packs at Costco, are made from polyester, nylon, modal, elastane, or blended synthetics.