These fur-babies are precious so please don't get upset when someone over-reacts wanting to protect their baby! Mine is still a kitten and bites or chews everything in sight, yours might be more well behaved.
So, to be fair, if the cat were able and inclined to chew the roof, PVC as a coating is not a good idea. Phthalates were banned in toys in the United States in 2008. In Europe, the ban extends to many products. And it is worse if DEHP is used as the plasticizer. Exposure to DEHP can damage the liver, kidneys, lungs, and reproductive system, particularly the developing testes of prenatal and neonatal males. It is known as a gender-bender.