Causes of Mercury Poisoning: Fish, Amalgam Fillings, Medicine, Environmental Risks and What You Can Do.
By Rebecca Rust Lee, Certified Health Coach November 6, 2025
This article organizes the biggest sources of mercury exposure — dental, dietary, medical and environmental — and shows you how to protect yourself. You can lower your risk by understanding where all the hidden sources of mercury can come from. You can find a guide to symptoms and how to chelate at maybeitsmercury.com.
Mercury Interferes with a Vast Number of Metabolic Processes and it is Easy to Get Exposed
In the book I co-wrote with Andy Cutler, PhD: The Mercury Detoxification Manual, we cite a 2017 journal article which states that mercury “can be differently associated with over 250 different symptoms involving the neurological, renal, respiratory, cardiovascular, hepatic, reproductive and immune systems with fetotoxicity and genotoxicity in humans.” Mercury interferes with a vast number of metabolic processes and small exposures accumulate and buildup over time.
Humans have always been exposed to some mercury in the atmosphere from volcanic eruptions, but mercury is so useful technologically that we have wound up getting unnatural exposures for centuries.
Here are some of the main ways you can get exposed to mercury:
1) Dental Amalgam (“Silver”) Fillings Off Gas Mercury Vapor.
Amalgam or “Silver” Dental Fillings are the biggest source of mercury exposure in the general population. They are about 50% elemental mercury by weight and off gas the easily absorbable and incredibly toxic mercury vapor. Anything that heats up these fillings, like chewing, hot liquids, tooth grinding or drilling can release this vapor. Risk considerations for this situation include the number of fillings, their age and condition, bruxism (grinding), age, pregnancy, and individual sensitivity.
ACTION STEPS
If your fillings are in good shape and you are not experiencing any mercury symptoms, you can take a “watch and wait” strategy. But keep in mind that the exposure builds up and as you get older, your body, in the face of this constant, low-level and cumulative poisoning, is less capable of maintaining its equilibrium. The prognosis for chronic mercury exposure is not good.
If you decide to replace your amalgam fillings, be sure to work with a “biological dentist” who uses isolation barriers, high‑volume suction, air filtration, and protective gear. Here is a good place to find out about such dentists: https://iaomt.org/
Consider nutritional support before and after dental work. Everyone who suspects they have mercury problems should take “the core four” which are two minerals and two antioxidants that particularly oppose the bad things mercury does to you. Here is a video about these supplements: Feel better fast! (Be careful with C supplementation around the time of dental procedure time as for some people this can interfere with sedation and pain killers.)
2) Mercury in Fish & Seafood
Mercury enters waterways, becomes methylmercury, and concentrates up the food chain. Larger, longer‑lived predatory fish tend to be highest in mercury as they have had time to accumulate it in their bodies. Fish have an enzyme that allows them to move mercury out of their brains and other sensitive organs. Mammals do not have this enzyme which is why fish can have high levels of mercury without getting sick. When we eat these fish, however, we can get very sick indeed!
A Table from the FDA Listing Mercury Levels in Fish:
You can use the following table to decide which fish you feel comfortable eating. A good benchmark is to look for a fish that is smaller than your dinner plate. Click here!
ACTION STEPS
Many people rely on canned tuna for their protein. Choose the skipjack over the albacore and don’t overdo it.
A good benchmark is to avoid any fish that is bigger than your plate.
Freshwater fish caught for sport from contaminated waterways sometimes have vastly elevated mercury levels. Check for local advisories.
3) Environmental & Occupational Sources
Coal fired power plants are a significant global emitter and mercury can travel for miles in the air before depositing in the soil or water
Current small-scale gold mines also pollute enormously. Past gold mines are still significantly contaminated
At home, sources include CFL bulbs, fluorescent tubes, mercury thermometers, some light switches, some batteries.
Old chemistry labs where mercury was spilled even decades ago can still be off gassing from between the floorboards.
Mercury can be found in unusual and unexpected places like this: mercury in a gym floor.
ACTION STEPS
Replace fragile items like CFL lightbulbs with mercury‑free alternatives.
If a CFL bulb or thermometer breaks, follow local spill clean‑up guidance (ventilation, no vacuuming, careful disposal). Here is one from the State of New York
If you are worried about your interior air, run a HEPA filter air purifier and change the filters regularly. You can also rent a device called a Jerome meter that analyzes the air for mercury vapor.
Don’t visit old gold mines!
4) Medical & Consumer Products
Mercury has been used medicinally for centuries. Until very recently, it was used as an antiseptic and as a diuretic. In some countries, mercurochrome, a mercury disinfectant, is still available.
The mercury compound, Thimerosal, was used in certain medical products until quite recently. Mercury is still used in “trace amounts” in the manufacturing process for some of these products.
“Skin lightening creams” are a massive, world-wide business and these products often contain mercury as an active ingredient. Here is a video about this topic.
ACTION STEPS
Heavy metals can absorb through the skin so think carefully about what skin care products you use.
Buy from sources that test their products. Report suspect products to local authorities.
5) Special Scenarios
Some hobbies may be risky. People involved in antique restoration still do “fire gilding!!”
Some antique jewelry (i.e cinnabar carvings), some antique mirrors may contain or be manufactured with mercury.
Cultural/folk remedies may occasionally include mercury compounds.
Pregnant women can pass their mercury burden on to the fetus.
ACTION STEPS
If you have an antique mirror, consider testing it for mercury
Be aware that some red, carved jewelry might be made from cinnabar which is mercury ore and will off gas vapor.
If you use Ayurvedic or TCM medicine, be careful where the remedies are coming from.
If you are pregnant and have amalgam fillings, DO NOT GET ANY DENTAL WORK until your baby is born and you have finished breast feeding. Although the baby may absorb some of the mother’s body burden through breast milk, we still encourage breast feeding.
FAQs — Causes of Mercury Poisoning
1. Are silver fillings safe? They contain mercury and they are not at all safe. They excrete small amounts of mercury that build up in your body over time. How well a person tolerates this toxicity is individual. If removing your amalgams, do it safely!
2. Does cooking reduce mercury in fish? No. Mercury is bound in muscle tissue.
3. Which tuna is lower in mercury? Skipjack/light tuna is generally lower than albacore/bigeye. Still use moderation.
4. Can air pollution expose me to mercury? Yes. Emissions travel and deposit widely, but you are not going to get significant exposure from breathing air unless you live next to a volcano or are hanging around a gold mining camp.
5. What household items still use mercury? Some CFL bulbs, neon tube lights, older thermometers/switches, and certain imported cosmetics.
6. Is thimerosal still common? It has been largely reduced/removed from many products, but is apparently still used in the “manufacturing process” and then filtered out.
7. Who is most vulnerable? Pregnant women and children due to neurodevelopmental sensitivity.
8. How do I gauge my personal risk? Review exposures. A Doctor’s Data essential elements hair test can be informative but needs to be interpreted by a knowledgeable person.
Call to Action !
If you have symptoms that come and go and change; if you have been to multiple doctors without much success; if you have a cupboard chock full of supplements and medicines to chase symptoms and if an underlying cause for your problems still eludes you, then you may have chronic mercury poisoning.
To find out if heavy metals are your problem, a Doctor’s Data Essential Elements hair test may be informative. You can order this test through Direct Labs, or from my Fullscript dispensary. (Email me to order a test.) Buy the book, The Mercury Detoxification Manual, and interpret it yourself, or book a consultation with me and I will do it for you.
The first step that every toxic person should take is to start “the core four” supplements that particularly oppose the bad things that mercury does to you. Just starting these 2 antioxidants and 2 minerals can make you feel a whole lot better.
The second step is to get your amalgam fillings removed if you have them. You will need to find a dentist who knows how to do this while keeping you safe. The IAOMT website is a good place to look for a proper dentist.
If you are toxic with mercury, you are probably taking many, many supplements. Run all your ingredients by our Do Not Do!!! list to make sure something is not making you worse.
And finally, you will need to start detoxing metals following the guidelines of The Andy Cutler protocol. Educate yourself because mercury is a powerful and dangerous substance and must be treated with care and respect. Do not do random things to detoxify! All the information is available for free in our Facebook support group. For an easy to follow and convenient guide there is my book: The Mercury Detoxification Manual. If you prefer to listen to the material, there is a workshop. Or book an appointment with me! I will walk you through it starting from where you are.
Learn more about symptom patterns in our post on mercury poisoning symptoms.
Review our advice on how to detox mercury.
