Are wheat bags safe?

Wheat bags as a form of heat therapy have been around for years, almost since microwave ovens were first introduced in a domestic setting in the early 1970s.  The idea of a microwave heated pad for pain relief on muscles, or to keep warm and cuddle, is popular because of its ease of use and safety compared with filling a traditional hot water bottle.  There have been, however, some horrendous accidents because of misuse of wheat bags, and as a result they have had a bad press which stays in people’s memories.  Whilst any accidents and deaths are deeply tragic, I want to examine the evidence behind the rumours, to see how widespread the problem is.

Wheat bag statistics

I spent some time delving into the murky world of government statistics, as I have a secret liking for facts and figures, especially at the start of wider research.  I actually found the numbers to be quite optimistic, as in terms of total accidental household fires the numbers have decreased year on year.  It makes a lot of sense, as we have seen an increase in use of smoke alarms, and the decrease in smoking, chip pans, and coal fires in the home.  So, it is good to know we are all safer than we were; thank goodness for radiators and oven chips, eh?  Sadly, our fondness for candles continues, and barbeques/firepits too, so those figures are not so sanguine.

However, the numbers of fires started by or involving wheat bags are not shown separately. On the one hand this frustrated my research, but on the other it seems positive that those figures haven’t shown up as significant for those doing the counting. Smoking, matches and lighters are all still large enough to be shown separately, some 10,000 fires a year in total, cooking appliances caused over 15,000 a year, and electrical problems over 13,000, while candles caused over 1000. In a more detailed table, they list upholstery, curtains, and even lampshades, but no mention of wheat bags. So far so good.

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Wheat bag fire reports

I looked at several websites and reports from local fire and rescue centres round the country, to try and discover more information.  Several of them do mention wheat bag fires, so yes, they are recognising this as an issue, but in every case their reports clearly state that the wheat bags had been left in the microwave too long, or left unattended under bedding.  They are all careful to say that the wheat bags are completely safe if you follow the manufacturer’s instructions.  One particularly gruesome site, the East Sussex Fire Rescue Service, has what they style a Black Museum, a list of pictures and reports of things which have caused fires.  Wheat bags are there, but so also are hair straighteners, bread jammed in toasters, hover boards left on charge (?), and my favourite, potting compost spontaneously combusting.  Don’t panic, Mr Mainwaring.

Newspaper reports

So, then I tried to track down as many press reports as I could, where a fire from a wheat bag had led to a fatal accident.  This is obviously not as rigorously empirical as one would wish, but it is largely what has influenced public opinion, so worth pursuing, I think.  Here is a quick summary:

Year      Place                      Person involved                Fire Service conclusion

2008      Leeds                     82-year-old lady                Left too long in the microwave and left under bedding

2010      Wythenshawe    79-year-old lady with Alzheimer’s.        Left too long in the microwave; she added an extra 0 to the timing and melted the entire microwave.

2014      Wallasey               83-year-old lady with memory problems            Left too long in the microwave and left under bedding

2018      Rotherham          77-year-old man                Left too long in the microwave and left under bedding

I also found seven other reports of serious fires without fatalities, caused by wheat bags, over the same 10-year period, and two reports of serious burns.

It goes without saying that any casualties or fatalities are deeply distressing, especially if they could have been avoided, and I don’t want to take that lightly.  But this is four deaths over ten years, compared to 1700 deaths on the roads every year.  It is also clear that these deaths were all elderly people, who for whatever reason didn’t follow the instructions and ended up putting a burning hot thing under their covers, which then led to tragedy.  The fire reports in each case said it was the misuse not the wheat bags themselves, and urged people to stick to the recommended heating times.

Wheat bags v. hot water bottles

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I think we will all be much safer if we understand the different types of heat between a hot water bottle and a microwave wheat bag, so we need to have a quick brush with science to get this clear.  We tend to assume that a hot thing is a hot thing, and they will all behave the same, but not so.  At the risk of stating the bloomin’ obvious, water doesn’t catch fire.  Water turns into steam when it reaches boiling point, its molecules jiggle around and push each other further apart, and therefore expand into a gas.  Which is how steam engines were invented, and why you should expel all air from your hot water bottle before you seal it.  This we know.

Why does wheat sometimes catch fire?

But wheat is made of different stuff to water, and its molecules behave differently.  This is crucial in explaining the secret of ‘Man’s red fire’.  When we heat any type of fuel to a certain point, the molecules break up, join with oxygen, and produce some gas (smoke), some light (flame), and some heat.  It doesn’t matter if the original heat is from a match, a magnifying glass, lightning, or a microwave, the effect is the same: fire.  This is the crucial thing, the chemical reaction from heating molecules makes those molecules produce more heat themselves, and they heat the next ones.  More heat.  Being produced by the material itself.  Not just the original heat which might have stopped, in this case the microwave has pinged.  Your wheat bag will keep getting hotter on its own.  If it is in the open air, this will reach a certain point and stop.  If it is under some other ‘fuel’ it will keep getting hotter, especially if you have overheated it in the first place.

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Remember that the reason we use wheat bags at all is because wheat is very good at heating up and staying hot. And remember also that small things catch fire quicker than large things, and that wheat grains are definitely small.  And that dry things catch fire quicker than wet things, and over time your wheat is getting dryer and dryer.  Which is why all those tests the manufacturers of wheat bags have to do, suddenly seem rather sensible.  The wheat bags have been heated and timed and tested to work at a certain temperature and stay safe.  Nuking your wheat bag because it didn’t feel hot enough to you, and putting it under some nice dry flammable bedding, is seriously dangerous.

Precautions when using wheat bags

So, what are the sensible precautions you need to remember?  Firstly, only buy wheat bags that are clearly labelled as complying with British Standard BS8433.  This is a voluntary safety standard, there is no legal requirement for manufacturers to comply, but reputable ones will make this a priority.  Secondly, make sure you buy a wheat bag with the instructions on the product label and not just on the packaging, because you will lose that and forget the details. (I have just counted over 13 different manufacturers on Etsy with no mention of British Standard compliance, and no instruction label on the product, and that was just the first two pages before I got bored). Thirdly, follow the instructions carefully, and make sure you know the wattage of your microwave. 

The instructions should also include points to remember, such as don’t heat it up again if it hasn’t reached room temperature, and don’t heat it up folded as this makes hot spots which can cause fires.  Make sure your microwave is clean, no grotty muck which will ignite, and check the turntable turns freely or else the microwaves will only be targeting one spot not all of it evenly.  It is also helpful to put half a cup of water in the microwave with your wheat bag to keep the grains from drying out. 

Wheat bags are safe

In the end, I believe I’ve found that statistically wheat bags are a lot less likely to cause harm than a huge variety of other things in common use, and they do offer benefits such as muscle pain relief, warmth and comfort.  The main thing to grasp is that they are not the same as hot water bottles, and they mustn’t be left in bed under the covers, and if you’ve got that clear then you will be fine.  But the overall conclusion from all of my research can be reduced to one simple sentence:  Wheat bags are safe if you follow the instructions carefully.