Understanding the Presence of Harmful Chemicals in Tea Bags

November 21, 2025 •

4 min read

According to a 2019 study by researchers at McGill University, a single plastic tea bag can release billions of microplastic and nanoplastic particles into a cup of hot water. These tiny particles are just one potential source of harmful chemicals in tea bags, raising concerns about safety for both consumers and the environment.

Quick Summary

Some conventional tea bags can leach microplastics, along with potentially harmful additives like phthalates and BPA, into your beverage. Additionally, chemicals like epichlorohydrin may be used to strengthen paper bags, and some teas have shown traces of heavy metals. Safer alternatives include loose-leaf tea or certified plastic-free bags.

Key Points

Microplastics are prevalent in some tea bags: Many tea bags, especially pyramid-shaped ones, contain plastics like nylon, PET, and polypropylene that release billions of microparticles into your tea when brewed.
Plastic additives can be harmful: Endocrine-disrupting chemicals like phthalates and BPA, which can cause hormonal issues, have been shown to leach from microplastics found in tea.
Some paper bags use harmful chemicals: Paper tea bags may be treated with epichlorohydrin, a potential carcinogen, for added wet strength.
Heavy metals can be present: Studies have found detectable levels of heavy metals such as lead and aluminum in some brewed teas, originating from the leaves rather than the bag itself.
Loose-leaf tea is the safest alternative: The most effective way to avoid chemicals and microplastics from tea bags is to use loose-leaf tea with a reusable stainless steel or glass infuser.
Opt for certified plastic-free bags: For convenience, look for brands that explicitly state they use certified plastic-free bags made from natural fibers like cornstarch (PLA) or cotton.

Unpacking the Microplastic Problem

For decades, the convenience of tea bags made them the standard for brewing tea. However, recent scientific research has exposed a hidden danger: many tea bags contain plastic, which can break down and release billions of microscopic particles into your drink when steeped in hot water. The issue stems from the materials used for both the bags and their seals.

The Plastics Found in Tea Bags

Different types of plastic are used in tea bag manufacturing, often for strength and sealing purposes:

Polypropylene (PP): A common type of plastic used as a sealant to prevent paper tea bags from bursting.
Nylon and Polyethylene Terephthalate (PET): These are synthetic polymers frequently used to make "silken" or pyramid-shaped tea bags. When exposed to heat, these can release a massive number of micro- and nanoplastics.
Polylactic Acid (PLA): Marketed as a plant-based 'bioplastic', some biodegradable bags contain PLA. While a better alternative to petroleum-based plastics, some studies show PLA can also release particles, and it requires industrial composting to break down effectively.

The Chemical Cocktails from Plastic and Paper

Beyond the physical plastic particles, there is concern about the chemical additives that can be released from these materials.

Endocrine-Disrupting Chemicals

Microplastics themselves can contain harmful chemical additives. Studies indicate that when plastic-based tea bags are steeped, chemicals known as endocrine disruptors, such as phthalates and Bisphenol A (BPA), can leach into the tea. These chemicals have been linked to hormonal disruption and other health issues in humans.

Epichlorohydrin in Paper Bags

Many conventional paper tea bags are treated with epichlorohydrin to add strength and prevent them from tearing in hot water. Epichlorohydrin is a chemical that is classified as a potential carcinogen, and though the levels in tea are likely very low, its presence raises a valid health concern. The bleaching process used to whiten some paper bags can also introduce chemicals like chlorine dioxide.

Heavy Metals and Pesticides

Some risks are not from the bag itself but can be present in the tea leaves. A 2013 study published in the Journal of Toxicology tested 30 different off-the-shelf tea brands and found levels of heavy metals in the brewed tea.

Lead and Aluminum: The study found that most brewed teas contained detectable levels of lead, with some exceeding safety standards, particularly for pregnant and lactating individuals. Excessive aluminum was also found in some samples. The study suggests longer steeping times can increase the level of heavy metals released from the tea leaves.
Pesticide Residue: The quality of the tea leaves themselves can vary widely. Lower-grade tea used in some conventional tea bags may be sourced from farms with less stringent regulations, potentially containing pesticide residues.

Potential Health and Environmental Impacts

While the long-term health effects of ingesting microplastics and these other chemicals are still under investigation, early studies point to potential risks. Microplastics can carry toxic substances and may lead to inflammation and oxidative stress. The environmental impact is more straightforward: the plastic components in billions of discarded tea bags contribute to plastic pollution in landfills and ecosystems, with some components taking centuries to degrade.

Safer Alternatives to Consider

Fortunately, tea drinkers have several options to minimize their exposure to these chemicals. Making conscious choices can significantly reduce your intake of microplastics and additives while still enjoying a quality cup of tea.

Loose-Leaf Tea: The most straightforward and effective solution is to switch to loose-leaf tea. This eliminates the need for any bag materials and often provides a higher quality, more flavorful brew as the leaves have more room to expand.
Reusable Infusers: For brewing loose-leaf tea, consider using a reusable stainless steel or glass infuser. These are durable, easy to clean, and free from plastic.
Certified Plastic-Free Bags: A growing number of brands offer certified plastic-free bags made from natural materials like cornstarch (PLA), cotton, or hemp. Be sure to check for reputable certifications that guarantee no petroleum-based plastic is used.
Buy from Reputable Brands: Choosing brands that are transparent about their sourcing and manufacturing practices is crucial. Higher-quality brands tend to use better materials and leaves.

Making the Switch: Loose-Leaf vs. Conventional Bags


Feature	Loose-Leaf Tea	Conventional Tea Bags	Potential Risk	Alternative Benefit
Material	None, uses an external infuser	Paper, plastic (Nylon, PET, PP)	Microplastic and chemical leaching	100% material-free brewing
Quality	Higher-quality, whole tea leaves	Often lower-grade dust ('fannings')	Lower flavor profile	Superior flavor and aroma
Toxins	Generally lower, depending on leaf source	Potential for epichlorohydrin, bleach	Potential intake of harmful substances	Higher control over ingredients
Reusability	Often reusable for multiple steeps	Single-use only	Higher waste, poor value	Better value, less waste
Environmental Impact	Minimal, compostable leaves	Contributes to plastic pollution	Non-biodegradable waste	Sustainable and eco-friendly

Conclusion

The potential for harmful chemicals in tea bags is a legitimate concern, largely stemming from the use of plastics that shed billions of microparticles when heated. While more research is needed to determine the full extent of the long-term health effects on humans, the evidence of exposure to microplastics, endocrine-disrupting chemicals, and heavy metals is compelling. Consumers can take immediate action to mitigate these risks by switching to loose-leaf tea, using reusable infusers, or carefully selecting certified plastic-free tea bag brands. This simple change allows for a purer, more flavorful cup of tea and a healthier choice for both personal wellness and the environment. For further reading on the microplastic study, review the research published in Environmental Science & Technology.

Note: While some tea bags may be made with bioplastics like PLA, these still may not fully break down in home composting, making plastic-free bags from natural fibers or switching to loose-leaf the most reliable options.

Frequently Asked Questions

Some tea bags can contain plastics like nylon, polyethylene terephthalate (PET), and polypropylene, which can release microplastics. Paper tea bags may be treated with a chemical called epichlorohydrin. Additives like BPA and phthalates can also be present.

Yes, studies have shown that some plastic-based tea bags, particularly those with a silky or mesh-like appearance, can release billions of microplastic and nanoplastic particles into hot water during brewing.

Not necessarily. While they avoid plastic bags, many paper tea bags are sealed with a plastic resin or are treated with epichlorohydrin to improve wet strength, which poses other chemical concerns.

No, not all tea bags contain plastic. Some brands have transitioned to using natural, plastic-free materials like plant-based cellulose (PLA) or cotton. However, it is essential to check the packaging for confirmation.

The most effective method is to switch to loose-leaf tea and use a reusable stainless steel tea ball or infuser. This bypasses any bag material entirely, ensuring a pure brew.

PLA is a plant-based 'bioplastic' and is generally considered a better option than petroleum-based plastics. However, some studies indicate it can still release microparticles, and it requires industrial composting to fully break down.

A 2013 study found that some brands of brewed tea contain traces of heavy metals like lead and aluminum, which originate from the tea leaves themselves. The risk may increase with longer steeping times.