The compression of corpses is proven at Belzec. It is the trans waxy fat residues reported from the core samples. As the naked corpses decompose under pressure, and initially heat, liquids leach out and the decomposing corpses squeeze together leaving a fatty mass, with no gaps. Only estimated calculation as to the volume of corpses per m3 can be made, but it will be the highest corpse density possible in a mass grave, where there is no cremation. Cremation makes that higher still.
What with 21,000m3 of disturbed ground, which alone makes Belzec one of the world's largest ever mass graves in terms of grave space, along with corroborating evidence of mass murders, exhumations and cremations, revisionists are resorting to creative thinking and arguments from incredulity, to try and wriggle out of the volume of evidence for Belzec as a death camp. They, of course, cannot evidence Belzec as a transit camp, or what ever other theory they come up with.