How It Works

Experimental crowd control: Riot foam

© Sandia National Laboratories

Sticky riot foam is a non-lethal riot control concept that has been proposed for some time but is yet to see widespread use, due largely to the risk of suffocation if it covers the mouth and nose. In addition, in trials of sticky foam as a riot control weapon it took several hours to completely decontaminate a subject using baby oil, as it adheres immediately to skin and clothing. Nonetheless, its use is still in discussion.

© Science Photo Library

Sticky foam starts as a non-reactive liquid that is stored at high pressure. When it is released, such as being fired out of a backpack-mounted dispenser, the atmospheric pressure causes it to expand to over 30 times its storage capacity. It is composed of rubbers, resins, fire retardants, oils and foam-stabilising chemicals and is about ten times stronger than syrup. The foam’s tensile strength allows it to stick to objects and significantly slow their movement, and it has been touted as being used to either slow a person or a vehicle.

© Science Photo Library

Above is a view of the first back-pack developed at the Sandia National Laboratories for dispensing ‘sticky riot foam’. The weapon can fire up to 10 metres and immobilises the target long enough for handcuffs to be applied. It was part of the ‘Less-than-Lethal’ programme of the US National Institute of Justice, and was originally intended to replace firearms as a ‘first resort’ weapon.

  • Meet

    I didnt knew that.
    Its a good article

  • Steve


  • Nigel Watson

    Sounds a messy way of dealing with crowd control. If several people are foamed they’d stick together like a bag of toffee. It would be easier to lay a trial of mobile phones into the back of a police van (disguised as an outlet of Comet or Currys).

  • Nigel Watson

    I meant trail of mobiles not trial – Freud slip.

  • Jay

    they should have declared it’s use in the london riots,
    it probably would have helped stop the riots after the 2nd week of august, maybe.

  • Bradley

    Haha..they should use this at occupy wall street..Those jerks deserve it…

  • FK Goff

    If it were more like sticky silly string, it could be used to tie arms together in a way like hand cuffs. But, the person ‘shooting’ the stuff would have to be a super sharp shooter.

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  • Esil

    Wait until it is used on you. How can anyone WISH that such a thing can used on others ? We are not living in the same world. Humanity really is a strange thing.