The fire retardent they use for PJ's washes out after a few washes. I for one would not want to wrap my little ones in chemicals. Most Moms wash all the baby clothes before they are used.
Now if I had a kid who was a fire bug, Iwould get him a water bed and keep a bucket of water handy. and take care to keep lighters and matches put up. We had one in our family, he burned the curtains on the porch, and two fields........If he had set the house on fire all the fire retardent fabric in the world would not help. I am one of those people who has developed enviremental alergies.......chemicals don't always make life better.
I think you find the warning on all children's prints. :)