It didn't have a chemical smell when we unrolled it.  It did take 3 days to reach it's full thickness...but the instructions did say it would take a while.  It is ALMOST 6 inches thick in the middle.  It's a little more than 5-1/2 inches on the sides...due to the way the manufacturer made the cover for their mattress being so tight.  Overall, it's a great deal.