Building materials that can result in unacceptable indoor air pollution levels can be items as common as carpeting and kitchen cabinets. Hypersensitive people must be wary of nearly everything, including paints and caulking. Of course, indoor air pollution can be caused by more than the house itself. If you build a healthy house, it will still be possible to foul the air by filling it with unhealthful furnishings. Permanent press fabrics release formaldehyde, while some pesticides and cleaning products can contain carcinogens.
Most unhealthy houses contain all three.
When brand new, carpeting is a problem because of its potential for outgassing. Outgassing refers to the volatile gases that are given off by new synthetic materials. New car smell is a good example. Besides the carpet itself, stain resistant treatments, the backing, padding, and adhesives are also sources of chemical pollution. When the EPA employees got ill, outgassing is what did them in.