The ones used in the parliament intrusion carried the marking "Creative Colour Smoke"
The ominous yellow smoke that engulfed the Lok Sabha chamber was an enormous security breach. Sometimes referred to as rocket candy bombs, these canisters are mostly benign and not very hard to put together as a do-it-yourself (DIY) exercise.
This should not be attempted at home since some of the ingredients are explosive.
The coloured smoke canisters are often used to send out distress signals or to draw attention. They are used in parties and pre-wedding shoots to add to the background. The armed forces use a more potent version that releases black smoke to camouflage their movements or to blind the enemy by creating a smoke screen.
In this case, the canisters seem to have been used as attention-seeking devices.
The ones used in the intrusion carried the marking "Creative Colour Smoke" - very easily available on the internet and cost just about Rs 75 apiece.
A website selling these online advertises them as "great for showcasing visuals and photography, as well as costume parties and Halloween decorations. Suitable for stage, movie, advertisement, TV, drama and other scenes. It produces a solid-coloured smoke effect. 100% brand new, quality assured, safe to use. It's the number one choice for film, TV, commercials, commercials and digital photography! Easy to use, just open the pull tab to use".
A cabinet Minister, on condition of anonymity, said, "Thankfully these were just smoke bombs. What if they were lethal chemical explosives? The results could have been horrendous."
Indeed, the intrusion exposed a big chink in the parliament's security armour.
However, the smoke bombs usually do not have any metal pieces and do not set off the metal detectors. The potassium nitrate could have been detected by odour detectors - the hand-held sniffing devices routinely used by the security personnel at Rashtrapati Bhawan. A modified version of this is used at airports.
Experts suggest that sniffer dogs could also have detected the potassium nitrate.
A 2020 advisory by the Ministry of Home Affairs on 'augmentation of K9s' lists the detection of acid salts like potassium nitrate as an essential requirement for trained dog squads. Sniffer dogs do a great job detecting explosives and on his visit to India, former US President Donald Trump's security detail used them to scan the media's camera equipment at his press conference in Delhi.
The main oxidiser in these canisters is a very commonly available chemical called potassium nitrate or saltpetre which is widely used as a fertiliser.
When packed in large quantities, potassium nitrate can be used in explosive devices such as improvised explosive devices, or IEDs. The infamous 1995 Oklahoma City bombing in the US used a truckload of potassium nitrate.
The fuel used in these canisters is finely ground kitchen sugar giving them the name "candy bombs".
A portion of baking soda is also added to the above components and this is done to ensure the sugar and potassium nitrate do not catch fire but only release a thick coloured smoke.
The colour can be any industrial dye available at textile dyeing units.
These chemicals are then mixed, put inside a tube, and sealed at one end. From the end where the smoke emerges, there has to be some form of ignition. A simple lighted incense stick can be used to light the mixture which then throws up the coloured smoke.
In the case of the parliament security breach, the canisters seem to have been activated with a pin mechanism since none of the videos showed the intruder lighting a fire. Also, everything happened fast.
These smoke bombs come in many colours - red, blue, orange, green or any dye that can be added to the mixture of potassium nitrate, sugar and baking soda.
A more robust security system could have very easily detected these canisters if only the threat perception was anticipated by the many agencies manning the parliament.
An added layer of foolproof canine security could have averted this embarrassment for the Indian security apparatus.