Hello Frank,

The UNMTC is certainly an interesting read but is determining what a product is for the purposes of transport. It does not define what An Explosive is. As you say, a simplistic question is posed on a ‘new substance’ and it is very hard for it to lose the ‘explosive’ tag once given. I.e. if long ago a substance was mainly manufactured to produce a practical explosive effect (BP in the 1950s) then ALL varieties of that substance inherit that labelling. E.g. Swiss No2 BP is sold as a small arms propellant but is labelled as UN027 with UNHC 1.1. Once a substance is deemed HC 1, it is a very slippery, almost one-way slope, keeping that status, but with an additional sub division. It appears impossible for changes in how a substance is used or shipped to improve (and down grade) its HC. Once a dangerous goods always a dangerous goods. It seems that only new substances have any chance of avoiding this trap. But my question was really aimed at what defines AN Explosive and whether BP meets that definition (apart from ‘they say it is’).

Sorry, you asked what I meant by moderately and strong confinement. I mean anything beyond light confinement. And by light confinement I suggest that a plastic or paper bag, a weakened Tetrapak or anything incapable of withstanding more than tearing force. As you are aware the explosive effect increases with the ability to resist confinement. A wooden box that peels like an odd banana (sides maybe hinged on the base edge only and lightly pinned) would offer good fire protection but little confinement in the event of ignition. A metal tin within an ammo (metal) box would give stong confinement and represent a bomb.

Hello Chris,
I agree that there are many definitions of ‘explosive’ and that is the crux of my question. There should, I think, only be two. One to define the event (“It was explosive”) and the other to define (a member of) a group of substances that explode (AN Explosive). I, and others, maintain that BP deflagrates and that this is different from exploding. I suggest that the word ‘explode’ has several definitions, one of which meets the requirements to help define AN Explosive. I feel that AN Explosive should be properly defined and this might be a good topic for the forum to discuss. The divisions into which Explosives are allocated seem also to vary between reference sources. Again a definitive set would help the industry and legislators. Gunpowder is defined as AN explosive in the 1875 Act but this act does not define what AN Explosive is. Incidentally, Blackpowder is a member of the Gunpowder group but so are other propellants. My question was about Blackpowder. Again I accept that in UK law Gunpowder is AN explosive but I feel that it, together with other mixtures should be called explosive substances (something capable of CAUSING an explosion) The word Explosive (as a proper noun) should define a chemical compound that can explode itself (i.e. damage it’s surroundings when initiated without confinement).

Hello Martyn,
I not sure that BP is ‘incredibly flexible’. Or an Explosive. I know that as a propellant it is variable in quality and performance but this is mainly down to cost and use (better ingredients and manufacturing detail are more expensive, and larger guns prefer courser grains). Although not my forte, in pyrotechnics, I would have thought that a rudimentary BP is used and that the other ingredients are the flexible part (metals for colours etc.) Again, whilst not an expert in blasting, it is my understanding that a basic BP is used for blasting and that it is used to fracture and coarsely break up material rather than ‘disappear’ it.
I would argue that many UN states treat BP more as a propellant for civilian use e.g. Switzerland where it can be bought over the counter, made, stored and used (for non exploding purposes e.g. shooting) without licence or certificate. The definition in chapter two (2.1.1.3 a) is for Explosive Substances NOT AN Explosive(s). My question was whether BP is AN Explosive and not whether it is an explosive substance. There is I think an important difference. I would suggest that BP’s intended use (certainly for Swiss Blackpowder) is mainly propellant. And if packaged well, when tested, might produce less hazardous results. Again BP has been deemed to have met the criteria for an explosive substance. It has not met the definition of AN Explosive because there does not appear to be one. The difference between BP and petrol does not answer the question, in that some explosives do not require oxidisers but all deflagrants does. Deflagration is a rapid combustion and combustion is oxidation thereby requiring oxygen. Chemical explosions do not necessitate oxidation (or the production of gases) for example Cuprous Acetylide explosively decomposes to form Copper and Carbon (and a lot of heat). Relying of very old and flawed testing is no basis for continuing to maintain the status of anything and especially explosives. If circumstances alter (safer procedures, ingredients, storage etc.) then the status should be revisited and reassessed. When HSE or its predecessor tested BP in metal tins it was in an era when this was thought to be a good idea by officials. It was also the era when smoking was promoted as healthy. More recent testing by HSE showed when better stored (plastic bottles in wooden boxes) ‘no mass explosion occurred’. They also showed that self-confinement did not alter the result (RR991). I would suggest that for an equal amount of explosive or deflagrant there is a huge difference. A kilo of open BP ignited burns the ground and gives a cloud of smoke. A kilo of TNT detonated will be hugely different in effect. Residence of 17th Century Delft and their fate is historic and anecdotal. It like comparing London 1666 and modern buildings. Just because something can cause an explosion does not make it AN Explosive. Finally, I do believe BP is over regulated in the UK. As a BP firearms shooter, I have to have an Explosives Certificate to attest to the fact that I am not disallowed from buying the stuff. It costs an inflated amount to buy because of the special transport arrangements imposed by its 1.1 classification. I cannot (it seems) hand 1g of BP to a trainee under instruction because it is ‘transfer of explosives’ to a non-EC holder. The police have to waste a significant part of their resources and budget in the administration of it. Yet, petrol whilst as hazardous enjoys less regulation. I am not trying to promote anything. But I do think that reducing BP’s status to that of 4.1 (Highly Flammable Solid) would be more appropriate. Remove ignition sources and it is very stable and safe. The police or Home Office do not regard BP firearms or BP as high risk for criminal pursuits.

Hello Peter,

BP is indeed a mixture of fuel and oxidizer. But not all BP is created, shipped or used for explosive purposes. Swiss powders are propellants for use in BP muzzle-loading firearms. The labelling specifically states ‘The sole intended purpose for the powder is use as a propellant for muzzle-loading guns and to load and reload ammunition’. I know petrol is a fuel and needs an oxidiser but it can both deflagrate and CAUSE an explosion. I suggest that BP is a potentially explosive substance but not AN Explosive.

Hello Maurice,

I would suggest that BP is in UNHC 1 because someone has supposed it to be AN explosive, badly specified the allowable packaging and then got the results that justify the supposition. If you supposed petrol to be an explosive and then performed the bonfire test with it in half empty metal containers (jerry cans?) you would get a mass explosion some what better that BP. I think it unwise to define something by saying it must be so. The criteria for placing a material into UNHC 1 is somewhat loose and uses terms such as ‘explosive substance’ and ‘explosive articles’. The former specifically says ‘a substance which is not itself an explosive’. It does not define AN Explosive. I understand the difference between explosion and detonation and believe that deflagration and explosion are separate events. I do indeed say that BP deflagrates but does not explode. I suggest that it can CAUSE an explosion. I suggest it will never detonate. Nitrocellulose is a generic grouping and some variants do not explode, they deflagrate and are used as propellants (not explosives) in ammunition (e.g. .22LR cartridges). Smokeless Powders are conditionally exempt from ER2014 as they are UN0161 covered in schedule 2. Your key difference between BP and Petrol does not distinguish BP as AN explosive.

Hello Simon,

I agree that the BP reaction is self-sustaining but I would suggest that under normal conditions (i.e. in temperate atmosphere) other combustibles and deflagrants would continue to react. They are not called Explosives because of this. BP does not burn IN water e.g. a BP fuze contained in cardboard submerged would not ignite or continue to burn. Only when the BP is protected from the water will the burn happen without external oxygen. My point about petrol was that it (and flour etc.) can CAUSE an explosion but is not AN explosive.

Hello Michael,

My question was whether BP is an Explosive not whether it can be used AS an explosive, or propellant or pyrotechnic. I actually use it solely as a propellant in pistol target shooting. In our usage and storage it is, in my opinion, safe; in that it is very unlikely to be accidentally ignited and if that was to happen the result would be a small fire hazard. I stress that this is the case for me personally and of course other people might be less safe. Again, potential to CAUSE an explosion does not make any substance an Explosive.

Hello Steven,

I agree that BP is a mixture and constitutes an explosive material. That is to say a material that can create an explosion. I do not disagree that some explosives combust and some deflagrate, without necessarily going on to explosion or detonation. The UNHC is a recommendation to guild national laws and regulations to be standardised and internationally accepted by other countries. In particular in regard to transportation and packaging for transportation. The testing performed to class a product is based on the packaging that is allowable for that product. Currently BP can be shipped and otherwise transported in (amongst other things) metal containers within metal outer boxes or drums. These enhance the hazard of it. If BP was always restricted to plastic, card or other low containment packaging, I believe retesting would reduce the HC to 4.1 (As the US adopts for internal small shipment). My question was not whether it should be regulated or to what extent. I question whether it explodes. I suggest that it does not, that it burns rapidly and has the potential to cause an explosion, like many other materials in the right circumstances. You mention BP used for ballistics, but so too are materials that are classed as Propellants. I would suggest that BP is a hazardous material but more in line with flammables.

In respect to your comment to another respondent to your question about not finding any reference to black powder and propellants being misused criminally may I also suggest you look at reports on incidents using the likes of pipe bombs.