Possibly the biggest gripe I have with poly is that it can be a hazard if exposed to fire.

Way back in the olden days, the 70s (when we rode on dinosaurs ... like a '74' Bonneville), when polyester was the fashion (Anyone here old enough to remember those gosh awful leisure suits?) the military started running into problems with synthetic underwear. People caught in fires were often escaping relatively intact only to find their underwear had melted onto and into the family jewels. Necessitating surgical removal and skin grafts.

After some testing it was determined that if the cloth had at least 50% natural fiber content it didn't adhere to the skin or cause the sorts of traumatic damage that the mostly synthetic ones did.

This may be the single exception to the straight 'Cotton Kills' line. A light and thin natural-fiber banana hammock helps keep the boys safe, if not always as warm as they might be. I tried silk, a good alternative, but I found my boys were just a little too happy with them.

The other related hazard is that the better synthetics are so good at insulating that if you get too close to a fire you can have it catch and be totally unaware of it. Right until the time it melts onto the skin. Several times I have had to beat out flames on a fellow camper.

My long hope has been that they would come out with a good low-cost Nomex fleece. Last I heard they had something like that but it wasn't anything like cheap. Find me a fireproof fleece that works as well as the existing poly and is not to much more expensive and I'm all over it.