As for 2.71 version there are two gases that is not dangerous and allow to manipulate temperature:

1. Aestusium to rise temperature of planet/moon
2. Frigusium to lower temperature

Your colonists also would love to have water, which can be added by using Water Vapour
And of course some oxygen to breathe.

That's the basics.

P.S. Does anybody know what the "Weight" parameter is used for?