Lead Leaching from Cups: The Hidden Dangers of Rusty Drinkware

circular connection
Jun 12
3 min read

A tragic case in Taiwan is raising questions about what we drink from every day. Here is what you need to know about lead leaching, and how to stay safe.

Stainless steel travel mug without lid, showing coffee residue inside, rests on wooden table beside black lid. Simple, neutral setting.

AI image: OpenAI

A Shocking Wake-Up Call

When news broke that a man in Taiwan allegedly died from lead poisoning caused by drinking out of a rusty thermal cup over many years, the story hit home for many. According to reports, the man had used the same cup daily for hot beverages like tea and coffee. Over time, corrosion inside the cup is believed to have allowed toxic substances, including lead, to leach into his drinks. The result was slow, silent poisoning that only revealed itself when it was too late.

The case has sparked widespread concern—not just about old or damaged drinkware, but about what materials are truly safe to use in the long run.

Can Metal Cups Really Be Dangerous?

Yes, in some cases. Many thermal metal cups and flasks rely on a vacuum-sealed layer to keep drinks hot or cold. To create this vacuum, manufacturers often use a tiny amount of lead solder at the base or between the inner and outer walls. If the cup becomes damaged, rusted, or worn out—especially when exposed to heat, acid (like coffee), or bleach—the seal can break down. When this happens, harmful materials may seep into your drink without you even noticing.

Lead poisoning does not happen overnight. It builds up gradually in the body, affecting the liver, kidneys, nervous system, and immune system. Symptoms are vague—fatigue, nausea, brain fog—and easy to miss until damage is advanced.

But What About Others, Like Plastic or Glass?

Plastic bottle, glass cup, stainless steel tumbler, and white mug on a wooden table against a plain beige background.

AI image: OpenAI

You are right to be cautious. Here is a quick breakdown of common materials and how safe they are:

Material	Is it Safe?	What to Watch Out For
Stainless Steel	Generally very safe	Choose high-grade (304 or 316). Avoid rust, dents.
Borosilicate Glass	Excellent and non-reactive	Fragile. Avoid leaded or colored glass.
Ceramic	Safe when labelled lead-free	Avoid decorative or old glazes without certification.
Plastic	Can leach chemicals when heated	BPA-free is better, but still best for cold drinks.
Crystal or Enamel	Often contains lead or cadmium	Not recommended for regular drinking.

How to Protect Yourself

The good news is that this is a preventable problem. Here are some simple ways to stay safe:

Inspect your drinkware often Check for rust, cracks, or discolouration, especially on the inside.
Replace old cups regularly If you have been using the same thermal flask for more than two years, it might be time for a new one.
Use gentle cleaners Harsh chemicals and scrubbing can wear away protective coatings and speed up corrosion.
Stick to certified safe materials Choose drinkware that clearly states it is BPA-free, lead-free, or food-grade stainless steel.
Skip the vintage or decorative mugs They may look charming, but many are not tested for daily use or may contain harmful metals in their glazes.
If in doubt, test it. If you are unsure about your drinkware's safety, look for clear labels like "lead-free" or "food-safe" from reputable brands. In some countries, lead testing kits for surfaces are available online, but they may not be reliable or accessible in every region. If you are concerned about long-term exposure, speak to a doctor about a blood lead test, especially if you have been using old or damaged drinkware regularly.

So... What Should You Use?

If you are looking for peace of mind, here are the safest everyday options:

Double-walled stainless steel (304 or 316), from reputable brands
Plain, borosilicate glass cups or bottles (no color or trim)
Certified lead-free ceramic mugs, preferably white or light-coloured

These materials are non-reactive, easy to clean, and safe for both hot and cold drinks when used properly.

The Bottom Line

Four drinks on a table: steaming metal mug, glass of tea, plastic water bottle, and glass of white wine. Neutral background. Minimalist.

AI image: Perplexity

The Taiwan case is tragic, but it is also a powerful reminder that everyday items can impact our long-term health in unseen ways. Drinkware is something we use every single day, often without a second thought. By paying a little more attention to what we sip from, we can avoid a slow buildup of toxins and protect our health for the long run.