Rugs can pad a crawling infant's knees and provide soft landings for a toddler adjusting to life as a biped. But synthetic-carpeting systems, and even most wool ones, are treated with stainproofing chemicals, mothproofing pesticides, and more. A 1994 EPA analysis discovered toluene and xylene, both neurotoxic substances, and benzene, a known carcinogen, in some carpet samples tested.
Wall-to-wall can't be taken up for a thorough wash, and pollutants can settle in deeper than vacuums can reach. Dust mites are a common trigger for asthma, and asthma rates are climbing among children. An estimated 6.3 million kids now suffer from the disease. Pesticides and herbicides sprayed on lawns, lead dust from your neighbors' renovation project—pretty much anything blown or tracked into your house—can settle into your carpet and hide out for years. In 1992 and 1993, 20 years after DDT was banned, researchers from the University of Southern California and the Southwest Research Institute found DDT buried in the carpeting of 25 percent of the 550 houses they tested.
Since babies spend a good deal of time on the floor, it can be best to leave them bare, with washable, natural-fiber rugs placed here and there. Susan Snover weaves colorful area rugs from recycled fabrics, such as old clothing and bits of leftover wool and upholstery from manufacturers. You can also buy untreated wool broadloom, finished with an edge.
Another option: Buy vintage! It's a form of recycling. When our nearly new and expensive wall-to-wall became impossibly stained with spilled juice and other toddler accidents (I won't elaborate), we replaced it with an old, all-wool Tunisian kilim in a bright palette that can be rolled up and sent out to be cleaned.