I have worked with the color paper process since about 1955. It has changed little in chemical composition since then, mainly in distribution of the chemicals and the removal of Ferri Cyanide from the bleach. If you use a stop bath, you may generate SO2 gas, but if not, there is little chance for any gas to form. High humidity is an enemy at 100F in high volume labs.

The bleach can emit ammonia, but only if the replensiment rate for the blix is off.