Norge had "stop 'n dry" drying for drying with or without heat without tumbling and the rack could be placed between two of the tub baffles at the top of the tub to hang things like nylons or it could be rested on two baffles in the lower part of the tub if you wanted to dry objects like tennis shoes, stuffed toy animals or sweaters.
Jon, Given the amount of air forced through the flame, I could imagine a gas dryer burning as clean or cleaner than a gas range with an oven burner nearly equivalent in BTUs. The lint would be the major factor, but probably not the fumes, anymore than they would be from a gas range.