Are Tea Bags Safe?
March 29, 2019
Paper tea bags are made from the albaca plant, a member of the banana family that is native to the Philippines. Albaca fibre is typically blended with unbleached wood pulp to increase its strength.
The issue of tea bag toxicity revolves around concern over treatment with epichlorohydrin.
Epichlorohydrin “Safe” Levels Around the World
Epichlorohydrin (ECH) is a wet strength agent – it increases the fibre strength of wet paper. It is also used as an additive to epoxy resins and in some water treatment flocculants.
The US EPA has listed it as a probable human carcinogen based on animal studies and allow up to 20 ppm (20,000 ug/L) (?) in drinking water.
“Currently (2008) Canada has voluntary standards of 2 µg/L for use of this substance in drinking water treatment (NSF International 2005b). This value directly corresponds to the drinking water guideline published by the US EPA (2007) but is higher than the guideline value of 0.4 µg/L set by the WHO (2004).” (Environment Canada)
The World Health Organization (WHO) recommends 0.14 µg/kg of body weight as the TDI (tolerable daily intake – no carcinogenic effects) - For 60 kg adult that’s 8.4 µg per day.
Occupational exposure limit for British Columbia, Canada is 100 ug/L (lowest in Canada).
California’s no significant risk level (NSRL) is 9 µg/day.
Based on data submitted to Health Canada, residual concentrations of epichlorohydrin in paper products treated with wet-strength resins range from 0.0342 to 0.0775 ppm (Environment Canada).
Assuming the paper has a density of 150 g/m2, the concentration of epichlorohydrin is equal to 11.625 µg/m2 (0.0775 ppm × 150 g/m2) or 0.00726 µg/in2 (Environment Canada).
Assume a tea bag surface area of 12.5 in2. therefore, each teabag contains (0.00726 µg/in2 x 12.5 in2) 0.09075 µg
0.09075 µg per teabag
You would need to drink 99 cups of tea to reach California's no significant risk level.
Similarly, you would need to drink 92 cups of tea to reach the WHO's tolerable daily intake level.
Reminder - The WHO suggests 8.4 µg/day for no carcinogenic effects (for 60 kg adult) based on a x10,000 uncertainty factor.
Epichlorohydrin intake from other sources: Health Canada predicts that a 60 kg adult will take in 0.15 µg per day from consumption of food wrapped in paper.
Epichlorohydrin in Common Tea Brands
Numi and Traditional Medicinals have publicly stated their bags are epichlorohydrin free.
Bigelow Tea say their paper manufacture uses resin which contains epichlorohydrin at safe levels. Link
Lipton, Tetley, Twinning, and Red Rose all reportedly use ECH.
Starbucks says their suppliers don’t use ECH.
(In the midst of finding better references for these)
Links and Notes
“No ECH residue was found in water kept in containers coated with epoxy resins (detection limit 3 µg/litre) (van Lierop, 1978).”
“No adhesives have been identified in Canada that contain epichlorohydrin and that are intended for consumer use.” Government of Canada
“the residual levels of epichlorohydrin in wet-strength resins are up to 0.0775 ppm, which results in an estimated daily intake ranging from 2 to 7.4 ng/kg-bw per day for the general population of Canada. (Environment Canada)”
“When released into the water compartment, almost all of the chemical (98%) will remain in this environmental compartment (Table 3). Due to “water-air” inter-media exchange, a small amount of the chemical (2.3%) will partition to air. (Environment Canada)
Brewed tea contains dihydrogen monoxide (DHMO) “Prolonged exposure to its solid form causes severe tissue damage. Symptoms of DHMO ingestion can include excessive sweating and urination, and possibly a bloated feeling, nausea, vomiting and body electrolyte imbalance. For those who have become dependent, DHMO withdrawal means certain death.” (Washington Post, 1997)
In water, Epichlorohydrin is (slowly?) hydrolyzed into 3-MCPD
A survey of commercially available soya sauces in Canada, they were found to contain an average of 16.2 mg/L. Therefore our dose would be 81 ug per teaspoon (5 mL) of soy sauce.
Health Canada uses a TDI of 1.1 ug/kg of body weight, or 66 ug per day.
I have no conflict of interests to declare. I do not receive funding from any tea or related companies. As always, feel free to contact me if I've made an error, misrepresented data, or if new research on this topic has come to light.
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