10 Most Dangerous Chemical Elements

There are somewhere in the region of 118 elements that are known of. The reason for being vague is that some are thought to exist but have never been observed. Of these 98 occur naturally. Very few of these elements are completely harmless and most present some risk in sufficient doses.

There are no hard,fast rules as to which elements are likely to prove most dangerous but we can divide the risks into three general categories. Those that are toxic, radioactive or highly reactive. Some even fit all three categories.

The thirty or so heaviest elements are all radioactive to some degree. Generally, the heavier the more radioactive. Listing those wouldn’t make for a very interesting top 10 deadliest elements so I’ve skipped a bunch of these and gone for the most exciting dangerous chemical elements.

10. Chromium (Cr)


photo: Atoma

Mention chromium and most people are thinking shiny car parts. It is also one of the elements that is essential to most higher organisms. But chromium has a dark side.
In one of its forms (hexavalent) chromium becomes a genotoxic carcinogen – that is something that can interfere with your DNA, increasing your chances of developing cancer.

Alarmingly there seem to be plenty of examples of industrial pollution involving hexavalent chromium, even in “developed” countries. Dangerous levels have been recorded within the past 5 years in both Australia and the USA.

9. Hydrogen (H)

Hydrogen combustion


The smallest and most abundant of all the elements, Hydrogen might not seem like the most obvious choice. However, if nothing else, hydrogen is incredibly flammable. Perhaps the most infamous case of hydrogen combustion was the Hindenburg airship disaster after which it didn’t seem like such a good idea to fly around attached to a massive tank full of highly flammable gas.
An added danger of hydrogen fires is that the flames are almost invisible. This means you could be incinerated before you even saw the fire.

The main reason I’ve included hydrogen on this list is that it is the key ingredient to all things acidic. The hydrogen ion or proton (H+) is what gives acids their acidic properties, some of which are considered extremely harmful. Chief amongst these are acids’ high affinity for water – upon contact with organic matter (e.g. human skin) intense dehydration will occur which is pretty much equivalent to burning. Sulfuric acid, for example, can cause deep burns within seconds. If you think that sounds bad the superacid, fluoroantimonic acid, is over one billion times stronger…

8. Lead (Pb)



Lead used to be used for everything; paint, eating utensils, toys and water pipes just for starters. Then someone noticed it was highly toxic. Whilst it might not be the most toxic element it is probably the most likely of these nasties you’ll come across

In high enough doses lead can be lethal. Symptoms include vomiting, staggering, weakness, seizures, coma and death. But this is rare, it is long term exposure that gets most people. Whilst still serious in adults, lead poisoning is particularly destructive in children. This is because it stunts the developing nervous system leading to irreversible damage. In short lead can permanently reduce your IQ.


7. Beryllium (Be)



Despite its pretty sounding name and the fact beryllium is made in stars it has some rather nasty properties. The dust from beryllium is so bad for you when inhaled that they even named a disease after it; berylliosis. This incurable condition causes lesions in the lungs similar to those found in tuberculosis. The symptoms are in fact often confused with TB and the long term effects may result in lung cancer.

Beryllium is a category 1 carcinogen, it is also very useful in a number of industries.


6. Fluorine (F)



Fluorine is a generally unpleasant substance. The unappealing pale yellow gas is corrosive, highly poisonous and will try to react with almost anything – often explosively. It is chlorine’s more unstable big brother and as we know chlorine makes bleach and mustard gas, amongst other things.

Just 25 parts per million (0.000025%) concentration of fluorine is potentially lethal. It acts by attacking the lungs, airways and eyes, effectively blinding and suffocating the victim. Think mustard gas, but worse and that’s fluorine.

On the positive side, fluorine is great for your teeth!

  • NCSteve

    Can’t believe thallium didn’t make this list.

  • Ian

    Why caesium? Why not frankium that is more dangerous when in contact with water

  • agileprovocateur

    The elements you use concerning natural radiation is actually known as just very very weak harmless emitters that can not mutate a fruit fly . Even if refined down to mass they are still just weak emitter but toxic to life yes not that humans come in contact with them refined . Now concerning man made radiation rule of thumb they are by comparison millions of times more energetic and dangerous than natural hence nuclear waste sites terrorist laws bal bla bla .

    A gram of natural refined emitters is about 1/10,000,000 of a curie and a curie is 37,000,000,000 atoms so a gram of natural emitter puts out around 160,000 harmless atoms but man made puts out 88 curies per gram or 88 times 37 billion vicious atoms pulsing right through your body and able to be picked up on a Geiger counter every second , big difference yea .

    When it comes to people being exposed to natural consider 10 prescription pills taken at once is considered a lethal dose for 50 percent of the population and consider 300,000 die each year of properly and appropriately prescribed prescription drugs yet no one died from the material you used .

    Concerning man made isotopes a single one will give you cancer in 20 to 50 years but some of up to 1800 auto immune diseases can and do show up before the cancer in study’s on animals because of that one man made atom . Consider Fukushima lost millions of pounds not a gram and is still blasting an made radiation up into the jet streams and ocean and will have to babysit Fukushima 3 meltdowns for at ;least 3000 years if they don,t run out of homeless first and lose the site .

  • disqus_Y5ZgQO83BY

    The “positive side” of fluorine statement was in sarcasm I hope.

    • Mokey

      fluorine is in toothpaste you numpty

      • EyeOfHorus 1493

        FLUORIDE is in toothpaste. YOU’RE the numpty.

    • TruthTalker9

      Fluorine is very healthy in small quantities if you aren’t an idiot conspiracy theorist who doesn’t know how to examine scientific evidence.

      • Random person

        Honestly it is not suppose to be in toothpaste period no matter what health effects are in Fluorine the point is that it is not suppose to be there and honestly you do not know WHAT the **** it is doing to your insides you can only estimate and guess. You do not normally consume it.

      • Random person

        If you have to use it in small amounts for you to not get sick then what is the point of using it because it must honestly be really bad.

      • Adarsh Tiwari

        But only in it’s compound

  • Elijah Kelley

    Why isnt chlorine in this

    • surfgatinho

      Because, as it says in the article chlorine is basically fluorine-lite. I could have listed both but I decided fluorine did the same but more.

      Admittedly it hasn’t been weaponized to the same degree as chlorine, but that is probably because it is too unstable.

  • jake

    FLUORIDE is the negative ion of FLUORINE and FLUORIDE is used in toothpaste in very small, so YOU’RE the numpty. FLUORIDE IS NOT FLUORINE. You can’t jut change the last three letters whenever you want.

    • Emily

      you change FLORINE to FLORIDE when it reacts with different elements…

  • Devid Kobozev

    What about Radium or Francium?

    • surfgatinho

      Caesium is basically just a more reactive version of francium. Also I didn’t want the list to just include radioactive elements – thought it would be more interesting to include other forms of toxins.

  • Paul

    Plutonium doesn’t occur naturally…

    • Pengwhiz

      Yes but also why does it say “500g of plutonium can kill 2 million people”? That is not true! Only half a gram kills 2 million people!

  • Daniel Blake Shoemaker

    What about Thallium, White Phosphorous, etc. 150 mg of white phosphorous would kill you min and 500 mg of thallium (Thallium sulfate) would cause very painful and slow death by destroying the entire nervous system. It a cancerous accumulative heavy metal that interferes with ATP and causes fluid retention causing cell brain white matter death, etc. Why don’t you add Thallium salts??

  • Pengwhiz

    There is one error that I spotted; “all elements 84 and above are radioactive”. There are so much more radioactive elements like thallium and uranium. They kill people in an instant. Other than that, this is an awesome article and I never knew that lead can lower the IQ. I thought it was just poisonous and can cause cancer. Nice job on this! Now I want to know how number 83 on the periodic table, bismuth, is able to cure and what famous medicines use bismuth. Thank you for presenting such a cool article.

  • Pengwhiz

    Stop calling each other numpty just because someone made a mistake (although the actual element is fluorine and fluoride is the molecule composed OF fluorine) so that was not very nice. People should not call each other names over mistakes. Make a little correcting would do WITHOUT the word “numpty”?

  • Matthew B

    I’m just looking for a dangerous material for my book. Summary of part of the book: He finds ______ (Material im looking for) It explodes, he wakes up and a few days later he discovers he has superhuman abilities.

  • H Paul Honsinger

    I was surprised that Actinium wasn’t on the list, given that we can’t even put together a more than a few micro grams of the stuff without it spontaneously exploding. It’s so nasty that no one can even tell you for sure what it looks like because no one has ever been able to make enough to be visible without it self destructing.

  • Ethan

    That’s 2 letters not 3