Em3 or Em4 ? I know only these two for Em4:
The format of this texture in Em3 is only .eft. This is a format you can't transfer to a format which you can work with. So there is no chance to work with Em3 textures.
Since converting .eft files back to tga doesnt seem to be possible at the moment, i tried to reconstruct the map through screenshots once (was same idea to use em3 map in em4):
Em3_freeplay.png
Althought its not quite the same as an native Texture - It would need rework in an external graphic programm,especially for the correction of the dimensions.
If helpful for you, i can upload it to webdisk? 
What you can do is load the map as a whole. Just copy freeplay.dds, freeplay.e3m and freeplay.eft from Emergency 3 to the Emergency 4 map folder. Then rename freeplay.e3m to freeplay.e4m. After that you can load the map just like a normal Emergency 4 map.
Just remember that the detailed polygons and light texture are broken and need to be fixed. (just delete the detailed polygons and change the light texture)
If u copy the em3 textures folder too, u dont have any light or detailed Polygon errors
Since converting .eft files back to tga doesnt seem to be possible at the moment, i tried to reconstruct the map through screenshots once (was same idea to use em3 map in em4):
Em3_freeplay.png
Althought its not quite the same as an native Texture - It would need rework in an external graphic programm,especially for the correction of the dimensions.
If helpful for you, i can upload it to webdisk?
This would be very helpful, in fact this is pretty much exactly what I'm looking for!
Also, in regards to converting .eft back to .tga there may be some potential there for someone who is a bit better at coding & hacking than I am. I've stumbled upon a program called Game Extractor by Watto Studios, through this I was able to open up a .eft and found that it is infact a fairly simple archive that contains 16 .cmp compressed images. Each of these images had a different bit depth, so I'm sure that digging around in the em4.exe and vision71.dll someone could probably find a way to write an exe that dumped the .eft file.
For those who may be interested in the process, here is the link to the Game Extractor software. You need the $10 paid version to open the .eft as that functionality does not appear to be included in the free version. I've included an image for reference.
Here you go:
Looks interesting - Did you tried to open the .cmp files with 7-zip or Notepad to see if something readable (e.g. header) inside?
