I built a double story 1600 x 600 x 600mm enclosure from untreated ply and it has been great. I also have some aquariums with mdf lids and they are OK also. The bonding agen in both is urea formaldehyde which gives off formalin if it gets too hot but is OK if you keep your heaters away from it. I don't use lights as a source of heat, only ceramics on a thermostat and uv lights. Make sure you have good ventilation. I use sand on the base of adult enclosures and astro turf for hatchlings and geckoes.