Ricin as a Terrorist Tool

This paper (full paper behind paywall)—from Environment International (2009)—does a good job of separating fact from fiction:

Abstract: In recent years there has been an increased concern regarding the potential use of chemical and biological weapons for mass urban terror. In particular, there are concerns that ricin could be employed as such an agent. This has been reinforced by recent high profile cases involving ricin, and its use during the cold war to assassinate a high profile communist dissident. Nevertheless, despite these events, does it deserve such a reputation? Ricin is clearly toxic, though its level of risk depends on the route of entry. By ingestion, the pathology of ricin is largely restricted to the gastrointestinal tract where it may cause mucosal injuries; with appropriate treatment, most patients will make a full recovery. As an agent of terror, it could be used to contaminate an urban water supply, with the intent of causing lethality in a large urban population. However, a substantial mass of pure ricin powder would be required. Such an exercise would be impossible to achieve covertly and would not guarantee success due to variables such as reticulation management, chlorination, mixing, bacterial degradation and ultra-violet light. By injection, ricin is lethal; however, while parenteral delivery is an ideal route for assassination, it is not realistic for an urban population. Dermal absorption of ricin has not been demonstrated. Ricin is also lethal by inhalation. Low doses can lead to progressive and diffuse pulmonary oedema with associated inflammation and necrosis of the alveolar pneumocytes. However, the risk of toxicity is dependent on the aerodynamic equivalent diameter (AED) of the ricin particles. The AED, which is an indicator of the aerodynamic behaviour of a particle, must be of sufficiently low micron size as to target the human alveoli and thereby cause major toxic effects. To target a large population would also necessitate a quantity of powder in excess of several metric tons. The technical and logistical skills required to formulate such a mass of powder to the required size is beyond the ability of terrorists who typically operate out of a kitchen in a small urban dwelling or in a small ill-equipped laboratory. Ricin as a toxin is deadly but as an agent of bioterror it is unsuitable and therefore does not deserve the press attention and subsequent public alarm that has been created.

This paper lists all known intoxication attempts, including the famous Markov assassination.

Posted on June 14, 2013 at 7:15 AM20 Comments


Gweihir June 14, 2013 8:43 AM

Au contraiere. With the successful attempts of the US government to decouple fear created by (potential) terrorist acts from the actual potential damage, Ricin is ideal: It likely does no to very moderate damage, yet people will be terribly afraid in large masses, because they do not get it. As terrorism is not about doing damage, but about creating fear, and due to the perfect alignment of contemporary terrorist goals and US administration goals (destroy US population freedom and thereby US society), I expect we will see Ricin “terrorism” in the future, either something genuine, or something staged by the FBI. After all, the FBI cannot stage bombings with non-functional explosives forever, people will just get tired of that and not generate the indented amount of fear anymore. But Ricin is nicely exotic and diabolic-feeling and when the first actually competent journalist digs up this paper it will already be too late.

Clive Robinson June 14, 2013 9:00 AM

As Gweihir points out is it makes excelent “sound byte scary” but practicaly…

For over a hundred years various Governments have been looking for (true) Weapons of Mass Destruction of which of the NBC triad only Nuclear has been a partial success (ie as a direct energy weapon like explosives).

But even that is a wash out without an effective delivery mechanism.

As has been found the very expensive way delivery systems for chemical, biological or dirty bomb / dust systems just don’t work anything close to expectation.

One terrorist group in Japan was exceedingly well resourced both financialy and with PHd level individuals in labs. After many attempts the best they managed was not much more than 50 or so people mildly affected (eyes and respiritry) with sarin…

The reality appears to be that delivery systems work only for fiction stories.

paul June 14, 2013 11:51 AM

For the same reason as the commenters above, ricin also probably makes a good area-denial weapon for certain kinds of enclosed spaces, especially ones that have a lot of stuff or furniture or clothed people in them.

We should all consider ourselves lucky that so many of the people who turn to terrorism actually want to (try to) kill a lot of people.

Hank June 14, 2013 1:49 PM

For propaganda purposes it’s a suitable weapon of mass distraction. Much like dirty bombs and EMP.

Simon June 14, 2013 2:25 PM

@Clive Robinson – why do biological weapons need an extraordinary delivery system? I understand an 800lb nuclear weapon needs a truck or a missile, etc. And I understand chemicals dissipate and require a certain concentration hence demand difficult to achieve dispersion. But bio? Why aren’t more people scared of what can be done on a desktop now, and once achieved you only need a handful of people to deliver. There are computer models that show what can happen. By the time hospitals in the UK or the US are in lockdown, thousands of carriers are all over the planet. Yeah, this isn’t available to terrorists in a kit, but the point is a delivery system is not the hurdle. It may be with chemical or nuclear, but not bio.

Adam June 14, 2013 2:55 PM

I’d love to know why anybody sends ricin, anthrax or even inert white powder to the president.

It’s not like the president would open the envelope in any circumstance. Most likely it would be caught far before then, probably by some guy during screening wearing a mask and gloves.

Even in the remote scenario that a letter reaches the president’s desk it is most likely a photocopy to preclude this sort of attack.

Someone capable of producing a toxin has so many other very obvious avenues of attack (e.g. salad bars as the Bhagwan Shree Rajneesh cult chose) that it would ill serve them to go for the target most equipped to detect it and provoke an immediate response.

Carl 'SAI' Mitchell June 14, 2013 3:44 PM

Bioweapons tend to have a problem: Lethality prevents further spread of the infection. The ideal bioweapon would be crippling and highly contagious, but rarely kill the host, or do so after a long asymptomatic but highly contagious period. Something like HIV is a better weapon than Ebola Zaire.
Fortunately most terrorists want an immediate visible effect, so a long contagious period or low lethality are counter to what they desire. Likewise most of what I’ve seen WRT government developed bioweaponry seems to lean towards the quick-kill type. This makes availability a hurdle, even if delivery isn’t.

NobodySpecial June 14, 2013 6:17 PM

It’s very difficult to engineer a bioweapon.

You would need to find a species that has a history of producing viruses that can make the species jump to people.

Then you would have to raise a vast number ( millions ) of them in conditions that boosted virus growth and cross contamination.

Then you would have to feed them large amounts of antibiotics so the virus had a chance to develop immunity.

Then you would need to move them around the country in vehicles that allowed their droppings and the virus to aerosol and spread to a large population.

I think if you did this – people would notice.

Jythie June 14, 2013 7:29 PM


Well, bio weapons require an extraordinary delivery system because it generally takes more then a ‘handful of people’ to do the trick, at least to any useful degree.

Nick P June 14, 2013 11:57 PM

Itemized history of secret US bioweapon experimentation


I know it’s a questionable source website of the type I’d rather avoid b/c who knows if they added something in there. Someone sent me this list many years ago. I did validate a few of the worst things on this list, like the Syphallis study and cancer experiments. Thought readers might like seeing it as a timeline.

Clive Robinson June 15, 2013 5:38 AM

@ Simon,

As others have pointed out bio weapons be they virus or bacterial have a life cycle that does not make them very suitable.

However there is a secondary issue, if you do find a biological entity with a suitable life cycle to make it weaponisable, how do you stop it coming back and biting you or those you claim to represent.

Let’s assume you are a member of a terrorist group the first question is where are you going to get the experts to find the ideal or near ideal biological entity for your weapon. You then have to mass produce it, refine it and carry out other processes to weaponise it, all without detection or infecting yourself and others in the geo-area you are doing it.

You then need to have this weapon be effective against your target population but still have some way of stoping it effecting the population of those for whom you are fighting.

With terrorism the likely target is first world WASP nations that just coincidently tend to have all the drugs companies and medical research personnel, whilst the population the terrorists are likely to be fighting for are not likely to have the research personnel and in many cases the indistry to produce antivirals or antibiotics in the quantities required, nor in many cases the medical personnel and facilities capable of providing the care required to protect the people.

That is unlike conventional weapons used for asymetric warfare bio-weapons realy don’t work in asymetric warfare where the attackers are not supported by a very well resourced first world nation.

Further if a first world nation is attacked and there is another nation with a “cure” the chances are the cure would be obtained in very short order and a high likely hood of that nation becoming targeted for conventional attack.

But there is also the “legacy mutation” issue, part of the history of vacination is smallpox and noticing that milk maids and other dairy workers who had come into contact with cowpox infected cattle appeared to have immunity to smallpox. That is cowpox and smallpox are very closly related, one is a minor issue for humans the other smallpox fairly major, very minor changes in a biological entity have wildly differing outcome. Biological entities mutate we see this with swine flu of which many new forms come about due to intensive farming practices, in most cases they are relativly harmless but occasionaly they are not. Whilst swine flu is relativly containable, bird flu from intensive farming can fairly easily spread to wild birds which are with just one or two exceptions the most wide ranging of animal vectors. One of the biggest medical fears currently is a bird flu pandemic that could kill millions (the last bird flu pandemic was nearly a century ago and killed many millions world wide at a time of human movment was a tiny fraction of our current mobility). This rapid rate of mutation will enevitably throw out a mutation that will badly effect humans or some other major species on which mankind is significantly dependant (wipe out bees polination drops rapidly thus food production shortly there after drops dramaticaly and mankind and other species starve). Thus each time you release a biological attack vector, no matter how carefully it’s tailored for limited effect has a risk of mutation, which in most cases won’t matter has a probability of becoming something much worse than the original weapon.

Figureitout June 15, 2013 2:19 PM

As Clive pointed out, I think the most deadly bioweapon (chemicals) will infect another species (bees). I don’t know how a lot of my crops pollinated b/c I don’t see nearly any honeybees anymore; maybe the wasps,yellowjackets, or flies/nats. But this mass-death we’re seeing w/ bees (saw one the other day die a painful-looking death on the pavement) has much more pain downstream for all humans than no more chicken/beef/pork…

I’ve tried to encourage people to grow their own garden w/o insecticides/pesticides b/c it’s not hard and it’s increasingly looking like an important survival skill.

NobodySpecial June 15, 2013 6:50 PM

That’s why anthrax was the bioweapon of choice for so long.
It’s a spore so can survive sitting in storage essentially for ever, you can spray it from an artillery shell or 30,000ft and it will remain viable.
It renders the area uninhabitable but is hardly likely to migrate from Afghanistan to the Eu.
And since it kills the host quickly it mutates relatively slowly unlike a flu virus

Barton June 16, 2013 11:01 AM

Two of the last four instances of people sending ricin laced letters have been frame-ups. More significantly, both attempts failed spectacularly.

I wonder about the thought process which would lead someone to believe that he or she could leave enough clues to lead back to their intended target, but not back to him or herself.

Wesley Parish June 17, 2013 5:45 AM

Sounds like HG Wells’ short story “The Stolen Bacillus”

“You see, that man came to my house to see me, and he is an Anarchist. No–don’t faint, or I cannot possibly tell you the rest. And I wanted to astonish him, not knowing he was an Anarchist, and took up a cultivation of that new species of Bacterium I was telling you of, that infest, and I think cause, the blue patches upon various monkeys; and like a fool, I said it was Asiatic cholera. And he ran away with it to poison the water of London, and he certainly might have made things look blue for this civilised city. And now he has swallowed it. Of course, I cannot say what will happen, but you know it turned that kitten blue, and the three puppies–in patches, and the sparrow–bright blue. But the bother is, I shall have all the trouble and expense of preparing some more.”

the point being you can lead a horse to water, but you can’t make him drink; the which point also applying to politicians, journalists, and the like perhaps being the reason why They Don’t Get It.

I saw one too! June 17, 2013 5:53 AM

So there I was, walking down the street, and guess what I saw on the ground? A bee! And you know what? It was dying! And not of old age, I can tell you. Oh no – it looked to be in a lot of pain. Wriggling, writhing. This was clearly the result of a nefarious act. The little guy was obviously a hapless vector for the trial run of some creep’s bioterrorism plot. What sort of monster would use a defenceless little bee to achieve his sick terroristic aims? Anyway you know the most amazing part? I felt its pain, man! Literally! A sharp stinging sensation on my arm – even swelling! And not just that! I felt its pain – BEFORE I EVEN SAW IT LYING THERE IN ITS DEATH THROES! You know, sometimes I amaze even myself with my empathy for nature.

Clive Robinson June 17, 2013 6:21 AM

@ Wesley Parish,

    I cannot say what will happen, but you know it turned that kitten blue, and the three puppies–in patches, and the sparrow– bright blue.

And now we know where Pierre Culliford (Peyo) got the idea for the Smurfs 😉

Which in turn may have given rise to Sir Terry Prachet’s “We Free Men”.

Figureitout June 17, 2013 2:56 PM

I saw one too!
–OK, haha; given the thread topic and the fact that some are looking to replicate flies/humming birds/etc. you may want to check that out. The errant “umbrella poke” is a thing of the past. Threats can be due to ignorance too, or attempts at market dominance like some food producers that want total weed/insect resistance. In my instance, I learned the hard way that too much water for corn leads to a horrifying fungi nicknamed “corn smut”.

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