They slash the tent at least 3 times - need for ventilation, noxious vapour.
There is many other reasons why they cut the tent, the most likely to escape quickly.
They seem to exit the tent extremely quickly without collecting clothing - noxious vapour.
There is many other reasons why they escape the tent quickly (this is where all theories starts)
They do not return to the tent - noxious vapour.
In this environment: open space and windy any chemical pollution will be disperse quickly, so will be possible to return to tent except situation when the source of chemical was dropped and was released slowly.
The rescue team describe the snow on the tent as "firn snow" requiring use of an ice axe to break through it - softened in a chemical reaction and refrozen.
The rescue described the snow as "The snow on the tent was 15-20 cm thick, it was clear that the snow was fluffy on top of the tent, it was hard. " - so generally snow deposited by wind as all the snow cover around the tent well visible on photos. Normal snow cover during winter in mountains.
The photos of the footsteps suggest wet snow - softened in a chemical reaction and refrozen.
No. To make raised footprints you must step in the snow, the snow gets compressed and hardens, and then the wind blows the loose snow away. Wind will never blown out wet snow, and after the wet snow freeze again it is not possible for wind to blow it out too. So for sure nothing melt the snow on the night when they left the tent. The raised footprints are proof of it.
Yuri K suffers a 30cm third degree burn to his lower leg, the only possible explanations can be (a) a small campfire or (b) electrical (e.g. lightning) or (c) - a chemical reaction.
Most likely it was burn from fire. If he will got that serious burn injuries from "chemical mist" on his leg that was covered why nobody got it on face or hands as they was exposed? As well, any "chemical mist" will be inhaled so the damage/burns to the lungs and airways will be very bad.
Significant number of burnt pieces of clothing found discarded around the campfire - as above.
So as above, no signs to chemical burns to exposed parts of body. The fact the the clothing is found around campfire indicate that the campfire was the source of the burns.
Strange photos from several cameras - chemical reaction.
If the films will get in contact with some chemical component they will be all damaged so only possible in the case of Zolotaryov's camera.
A lack of frostbite, even though most of the group are in their socks and for a considerable period (hours?) many of them display no frostbite - warming due a prolonged chemical reaction over a considerable area.
The lack of frostbites suggest that the body parts never get warmed or the dead happens fast enough so was no time create the frostbites. Many people that die from hypothermia in winter do not have any frostbites.
Signs of bleeding head orifices, vomiting, lung oedema - chemical poisoning.
Bleeding/foam from nose and mouths is a sign of lung oedema. Vomiting and lung oedema happens during hypothermia, so no need of chemical poisoning to have bleeding head orifices, vomiting, lung oedema in this case.
- Zinaida's face is recorded in the autopsy as "abrasions", curiously none of these abrasions show any direction of abrasion including an eyelid. - chemical peel.
- In the morgue it is noted that the victims clothing displayed a purple glow - chemical luminescence.
- At the funeral of Zinaida and Yuri D it is noted that their hands and faces are dark orange. Yuri D's skin tone being compared to an African - unknown reaction due to chemical exposure.
- Lyudmila's face is recorded as "yellow brown" except that the morgue photo shows a white chin - chemical exposure with chin protected by clothing.
- A number of the group display white hair where none previously existed - bleaching?
All bodies were at some stage of decomposition, autopsy of the first 5 was done days after bodies were found and already defrosted for some days, the last 4 were exposed for 3 months and already a bit defrosted too. Skin color changes is natural process during the decomposition so is relay hart to have any conclusion from it. It is normal that they not looks naturally.
On dragging the tent to the helicopter land site it is noted that the fabric is weak and easily tears - chemical exposure
It was old tent, some reports say that already repaired many times. Additional for the last 3 weeks exposed permanently to the elements make it even more weak so nothing strange that the fabric could break easily.
The tips of young firs at the treeline seem to have been burnt - killed due to chemical exposure.
No. It is natural thing in mountains or any other place where plants are exposed to strong winds and low temperatures. Winter burn tree.
Reports of orange snow. n.b.. afaik watermelon snow is always pink.
The watermelon snow could be bloody red too, and looks orange: https://snowbrains.com/wp-content/uploads/2019/08/44822364_1483226128479594_8034938209787817282_n-min.jpg
Plus there is many other possibilities of getting orange snow including industrial pollution or natural like sand from Sahara or Gobi.
The above evidence (combined with my conjecture) fits a scenario where a "corrosive chemical mist" is blowing across the location down the slope and into the forest, with this mist occasionally igniting.
I do not say that "corrosive chemical mist" is not possible, just many things could happens in more natural way or have many explanation.
I think the type of the chemical agent is very narrowed now. It must be:
-creating burns to skin and fabric;
-leave orange sediment;
-possible to distribute in the form of mist;
I guess some expert of chemical stuff could know if something like that exist.