productivity by creating offices with better indoor air. They found that the financial benefits of improving office climates can be 8 to 17 times larger than the costs of making those improvements (W. J. Fisk, 2000). Not making these improvements can have other penalties, since sick buildings have become serious legal liability problems for owners faced with suits from debilitated occupants and employees. While the U.S. EPA has listed building sickness as one of the top five health threats to Americans today, existing occupational health and safety legislation offers little protection to office workers who commonly do not have the option of even opening windows for fresh air as they do at home. Legislated standards today are based on limitations of exposure to single chemicals in manufacturing plants. They have no way of dealing with the synergistic effect of the mixing of many kinds of volatile organic compounds (VOCs) in the chemical soup that constitutes the air of most contemporary homes and offices. Monitoring levels of toxic substances in buildings is difficult for the same reason. Buildings officially certified as safe often continue to cause major health problems for occupants (Conlin & Carey, 2000). The offending substances that I am concerned with here (i.e. excluding mould, combustion gases, etc.) include VOCs like formaldehyde, toluene, naphthalene and limonene. A study carried out jointly by the State of Washington, the USEPA, and a consulting firm found over 400 different VOCs emitting from the 96 primary construction and furnishing materials. The most frequently emitting VOC, toluene, offgassed from a third of tested materials. The offending materials include paints and stains; adhesives; caulks and sealants; carpets; resilient flooring; furniture; particleboard and