The chemical used is not only dangerous to moths, but there are sensitive people who are bothered by it as well. Even with very old carpeting, having virtually no outgassing characteristics, there are other reasons to avoid this common product. There are many people who are allergic to house dust. House dust can be composed of a wide variety of materials. We all shed a little bit of dead skin each day.
Pets also shed bits of skin that have their own particular allergic potential.
As synthetic materials age they can become brittle and begin to decompose, contributing to house dust. Sunlight passing through a window onto the carpeting will hasten this deterioration. As the tiny bits of carpeting break off, they contribute to the house dust floating around in the air. Synthetic house dust can irritate the sinuses and respiratory tract like any other type of dust. It can cause some other problems as well.