Plug the fridge in and leave the door open - keep you nice and cool 
After having read through this topic it seems that a substantial number of people do not beleive that drivers have been gassed whilst sleeping in the cab and have put forward several theories as to what they think is happening. Most if not all of these theories are based upon the idea that the drivers who claimed to have been gassed had had one too many sherbets and either gassed themselves with the gas stove, or woke with a bad hangover. All these theories are based upon the so called lack of proof - and coloured no doubt by the sad fact that our industry employs more than its fair share of Walter Mittys.
The problem with providing proof is that many drivers simply do not report the incident to the local police, either through not being able to speak the local language or through simply getting on with the job and getting going.
Another problem is that quite often the local police, particularly the Gendarmes in France arent really interested and have little or no inclination to investigate the incidents. it is therefore very difficult to provide proof if the incidents are not reported and if they are, the police cannot be bothered to follow up the allegation.
One particular post states that according to an anaethestist it is impossible to knock someone out with ether - a common theory is that Easy Start is used and it contains ether and is also readily available in service stations across europe. I am not medically trained so I will not argue against a medical professional, however if someone is already asleep then the effect of ether may well stop someone waking whilst a cab is turned over. What is more worrying is that someone one day may never wake up again.
After having been gassed at the Shell at Ruffec (N10 northbound) about five years ago i have no doubt that it happens. On the night in question I had parked up at around midnight, had a brew and gone to bed - no beers or alcohol as I had none with me. As for gassing myself with the butane from the cooker, I suspect that I would have been more likely to asphyixiate myself and not have woken if the gass had been left on. Also I doubt I would have stolen all my money, two mobiles, all the food and beleive it or not, my dirty laundry too. - as well as forcing my own cab door locks.
My good friend Welshboyinspain cannot vouch for the incident involving me, but I am sure he is aware of a mutual friend gassed near Valencia (Baldy John). Whilst many will refuse to beleive that this is happening, you can rest assured that it is. My great concern is that is a driver going to have to die before the authorities in europe take this problem seriously.
I have read with interest your threads on Gas attacks and can add to them , i was doing Swiss for a few years and am based in ireland, i used to turn in Liverpool and get back to Belgium on the Lux Motorway, i parked for the night ,normally around Midnight and toodled up to the BP to fill in the morning, the First time i was "āGassedā"i was just dropping off to sleep when i felt movement, realised that someone was on the catwalk, sat bolt upright on the bunk, it was a big Iveco cab, and promptly went straight to sleepā¦ woke in the morning, did a tour of the trailer, no onsite toilets, got going to Lux, filled with fuel, parked up to get a coffee and when i tried to lock the drivers door, found it to be broken, someone had stuck a screwdriver in and gouged out the key slot, same on the other side. I am a light sleeper and can testify to the fact that i would hardly have left someont to their own devices, dancing on the catwalk, i heard a van next to the truck,and voices, just before i conked out, i forgot to say that when i woke up i had no immediate memory of the nocturnal activity, it was,nt till the day after that the chills went down my spine as things clicked and i remembered it all.Luckily for me they failed to get in. The second occassion was in Belgium again, first services after Bruxelles, Lux bound, slept and slept heavy, awoke to find the back doors open on the trailer, boxes and packing all over the place, it was agroupage load and they sorted through aload of stuff to rob anything they thought valuable, i repeat, i am a light sleeper an d armed with the knowledge of thieves rapists ilegals etc i used to jump if a cat passed by the trailer. So anyone who thinks that all the stories are just that, think on, the Belgo Police also issued a warning to all trucks, not to park anywhere until reaching either Lux or France, and that tells all. I also met a lot of other drivers with similar stories, and running money days were long gone at this stage.
Common problem when driver and his mate are on a long tripā¦ someone always sneeks one out and dont own up to itā¦hahahaha 
Harry Monk:
But the trouble is that cs gas would not make you go to sleep- quite the opposite. I imagine there are many here who have done Army training and who have been exposed to it during training, who will confirm this.
Confirmed. It would not be possible to sleep through the eye-watering, cough-inducing, throat-burning āfunā that is CS. 
eveningstar.co.uk/news/first ā¦ t_1_654569
It seems that Hydrogen Sulphide may work, but still uncontrollable!