Heat Not Burn Safety Update

Over the last year we’ve seen a lot of progress for heat not burn products, with the iQOS now available in several countries and a few new devices set to be released soon. The market looks like it could be on the brink of some serious growth, and within a few years HnB could have made as big a dent in smoking rates as e-cigarettes already have.

There’s one thing still missing, though. If heated tobacco products are really going to grab a sizable percentage of the cigarette market it’s important that their makers can show they’re safer than smoking. As we’ve mentioned before, common sense tells us they pretty much have to be a lot safer, because the tobacco isn’t being burned, but there’s a distinct lack of actual data. Isn’t anyone doing the research on this? It turns out the answer is yes.

Of course, you won’t see this research appearing in the medical journals just yet, because it’s actually being carried out on behalf of the tobacco industry. Philip Morris International have invested more time and money in HnB than anyone else, and a lot of that has gone towards looking into how much risk can be removed by switching from lit to heated tobacco. Some world-class laboratories have been asked to investigate how HnB is working and what that means in terms of health effects. Last week Heat not Burn UK got a chance to visit the Cube, PMI’s European research HQ at Neuchatel in Switzerland, to find out what’s going on.

How hot is too hot?

By now everybody knows that smoking-related diseases aren’t caused by tobacco; it’s the combustion process that creates the worst toxins and cancer-causing substances. Tobacco-free herbal cigarettes aren’t any better for you than Benson & Hedges, because you’re still inhaling burning plants. However, PMI have found out that making a safe HnB product isn’t as simple as not setting fire to the tobacco.

The tip of a lit cigarette, between puffs, is at between 600°C and 800°C; when you take a drag on it this rises to over 900°C. That’s the sort of temperature tobacco burns at. However, at much lower temperatures it goes through a process called pyrolysis, where it’s being broken down by heat but not actually burning. Pyrolysis starts at around 350°C, much lower than combustion temperatures – and pyrolyzing tobacco still gives off a lot of nasty chemicals. Not as much as burning it, of course, but probably still more than you really want to be inhaling.

So the trick to safe HnB is to heat the tobacco to just below the point where pyrolysis begins. If you were wondering why iQOS heats its sticks to 350°C when tobacco doesn’t start burning until hundreds of degrees above this temperature, now you know. PMI have opted for the highest safe temperature, where there’s little or no pyrolysis going on but the tobacco is still hot enough to generate a decent vapour. Because HnB products like iQOS, Glo and PAX 2 are electronically controlled it’s easy to get them to produce a constant temperature and avoid pyrolyzing or burning the tobacco.

Tracking the toxins

Obviously the big question is, what effect does HnB have on the levels of chemicals you’re inhaling? It’s unrealistic to insist on zero chemicals, because many of the toxins in cigarette smoke are very common substances. For example, smoke contains high levels of formaldehyde – but human bodies contain formaldehyde, too. Our metabolism produces it, and there are detectable levels of it in exhaled breath. What we’re looking for are levels that might not be zero, but are much lower than you’d get from a cigarette.

To test this, PMI analysed the smoke from a reference cigarette – this is a standardised cigarette used for lab testing – then compared it with the vapour from their two HnB products. One of these is iQOS; the other, known as Platform 2, hasn’t been released yet but works in a different way. What they found was that for every chemical they tested, levels were dramatically reduced in both HnB products. The highest levels were for ammonia, with iQOS having about half the level of a cigarette and Platform 2 around 40%. Is that enough to worry about? No; even cigarette smoke doesn’t have anywhere near enough ammonia to be an issue. For the other chemicals they tested levels were reduced by at least 80%, and in most cases 90 to 95%. Overall it looks like HnB eliminates more than 90% of the harmful chemicals found in cigarette smoke.

One impressive point about PMI’s research is that they’ve been extremely thorough. Different agencies have different lists of chemicals in smoke that concern them. For example the FDA have a list of 28 different substances; the International Agency for Research on Cancer’s list has fifteen. To be on the safe side, Philip Morris have simply combined everyone else’s lists; they test for fifty-eight different chemicals – far more than anyone else does.

Attention to detail

PMI aren’t just measuring what’s in the vapour; they’re also testing smokers who’ve switched to their HnB products to see how they compare with people who’ve either quit entirely or continued to smoke. What they’re doing here is looking to see if switchers’ blood chemistry is more like a smoker or a quitter. For every chemical they’ve tested – including carbon monoxide, benzene and acrolein – HnB users either have identical levels to smokers who’ve quit entirely or (for acrolein) the level is slightly higher than a quitter but much lower than a smoker.

At Heat not Burn UK we might not be scientists, but we do know how science is supposed to be done. The research that’s being carried out on the health effects of HnB is very good science. It’s extremely thorough and detailed. The actual analysis is being carried out by independent labs, which should deal with any accusations of bias. PMI are being completely open about the experimental methods, so anybody who has doubts can replicate the research themselves.

Why so modest?

That leaves one question: With all this research to back them up, why aren’t PMI shouting from the rooftops about how safe HnB really is? Most likely that’s down to an understandable wariness of being sued. If they say that iQOS is 90% safer than smoking, and then at some point in the future evidence shows it’s only 89.9% safer, how long is it going to be until swarms of Californian lawyers descend on them with a fistful of class action suits? Not long, probably.

So, for now, they’re playing a cautious game. The data is there, and steadily growing. Sooner or later it will be presented to some government agency, probably the FDA, and they’ll confirm that these products are much safer than smoking. That’s when the manufacturers will start publicising it. Until then we’re just going to have to rely on common sense.

How safe are tobacco vaporisers?

Rumours are circulating that tobacco vaporisers and other heat not burn products might not deliver on the reduced harm that justifies the products’ existence. Not all these health claims are new, of course – they’re as old as the products themselves. Heat not burn probably has more potential now than ever before, though. Earlier attempts to sell the technology failed, probably because it was just too different from what smokers were used to.

That’s all changed over the last few years. The popularity of electronic cigarettes has grown at a stunning rate, and despite the fake concerns of many public health charities almost all the people who use them are, or were until recently, smokers. The key point about that is that by any sensible definition e-cigarettes are far more different from traditional cigarettes than any heat not burn product is. E-cigs don’t even contain any tobacco, while heat not burn products do. In fact most of the ones in the pipeline just now include something that’s recognisably like a cigarette. The only exceptions are loose tobacco vaporisers like the excellent PAX 2. Phillip Morris’s iQOS uses cigarette-like tobacco sticks, while RJ Reynolds’ Revo looks just like a cigarette and even works like one; you simply put it in your mouth and light the end.

So the companies interested in heat not burn technology are gambling that if smokers are willing to switch to something as unfamiliar as a tank full of liquid with a battery to heat it, they’ll be even more enthusiastic about something that retains the familiar tobacco. They could be right; although vaping has become widely accepted among smokers there’s still a significant number who aren’t tempted.

The fear industry

The problem is that heat not burn is still at the stage where it’s very vulnerable to health scares. E-cigarettes have suffered badly from this; media coverage has been so bad, and misinformation from anti-vaping groups so vicious, that a majority of American smokers believe vaping is at least as harmful as smoking; the truth is it’s at least 95% safer. If so many terrifying rumours can be spread about vaping, though – where users are inhaling vaporised liquid – what can the fearmongers do with a product that contains actual tobacco?

It’s complicated by the fact that heat not burn is a much broader category of device than e-cigarettes. There’s an incredible variety of vapour products, but no matter how different they look, they all function in basically the same way. The battery heats a coil, which draws up liquid through the wick and vaporises it. Once you’ve shown that one e-cig is relatively safe to use, you can be pretty sure that your conclusions apply to all e-cigs.

Heat not burn is different. Some devices heat loose tobacco in a chamber, using an electric heating element. Others wrap the element around a paper tube of tobacco. Revo doesn’t have any electronics at all; it uses a charcoal pellet to generate heat. These devices share the same basic principle – heating tobacco to liberate flavoured vapour and nicotine – but they work in very different ways. That means conclusions drawn from studying one product don’t mean much for others.

The product that’s causing the most concern is Revo. How much of that is down to the fact that it looks just like a cigarette, it comes in packs just like a cigarette and it’s used just like a cigarette? Who knows? There are some legitimate reasons to worry, though. For a start, heat not burn isn’t an entirely accurate description of the Revo. The tobacco isn’t burning – in theory, at least – but the charcoal pellet that heats the whole thing certainly is.

How much burning is too much?

Burning charcoal is a notorious producer of carbon monoxide; lighting half a dozen disposable BBQ grills in a closed room is an increasingly popular way of committing suicide. The level of carbon monoxide emitted by a Revo is obviously much lower – but regularly inhaling small doses of CO is one of the most dangerous things about smoking cigarettes. The constant respiratory stress caused by the gas eventually damages arteries and leads to heart disease. The fact that Revo relies on charcoal has to be a point against it.

There are also questions about what exactly the Revo is vaporising, and even if vaporising is all it’s doing to the tobacco inside. Electronic devices, like iQOS, can maintain precise control over the temperature of the heating element. There’s almost no way an iQOS or PAX 2 is going to burn the tobacco you load in, unless you abuse it. Is the same true of the Revo? RJ Reynolds say so, but it’s hard to be sure. Because it does involve combustion, adding more oxygen to the process can raise temperatures. Take an unusually hard puff, or use it outside on a windy day, and the temperature could easily spike above the point where the tobacco is actually burned.

There’s no evidence that this is happening with Revo, but it’s certainly a theoretical possibility. Even in normal use the tip gets hot enough that many of the chemicals found in tobacco smoke can be vaporised. These include acetone and ammonia, as well as the monoamine oxidase inhibitors (MAOIs) that make tobacco smoke many times more addictive than pure nicotine.

It’s still pretty safe

On the other hand, while these worries are real, they probably aren’t very significant. It still seems to be a no-brainer that, because the tobacco inside isn’t being burned to ash like it is in a cigarette, Revo is going to be much less dangerous than a traditional smoke. There is also a spectrum of risk with heat not burn products. Electronic devices are likely to produce a far cleaner vapour than anything that involves combustion. Are they as safe as e-cigarettes? Because they contain tobacco, probably not. Are they safer than burning anything and inhaling the result? Yes, they almost certainly are.

So far there’s no evidence that even begins to suggest smokers shouldn’t try heat not burn. Even a Revo is going to be a lot safer than a normal cigarette; iQOS should approach the safety of a typical e-cig. If you’re already a smoker, and thinking about giving heat not burn a go, safety is not something that should affect your decision. Compared to smoking they’re safe enough; that’s what matters.

How safe is Heat not Burn?

One of the things you’ll hear a lot from anti-smokers is that 70% of smokers want to quit. If you actually talk to smokers you’ll probably hear a very different answer. Most of them don’t want to quit at all, because the truth is they enjoy smoking. They know they should quit, because smoking is undeniably bad for your health, but that’s not quite the same as actually wanting to. If scientists announced tomorrow that they’d got it all wrong and smoking was completely safe, you can bet nobody’d be interested in quitting. The appeal of Heat not Burn products is that, potentially, they can offer the enjoyment of smoking without most of the health risks. That raises a crucial question: How safe are HnB products really?

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