A toxicologic approach for evaluating cases of sick building syndrome or multiple chemical sensitivity.

The nonspecificity of symptoms and exposures commonly reported as "sick building syndrome" is very similar to that reported for the condition termed "multiple chemical sensitivity (MCS)." In many instances health care practitioners are divided on the reality of the latter. As in all scientific cases of possible cause-and-effect relationships, an organized, dispassionate approach should be used to evaluate each claim of MCS. Most obviously, known medical conditions must be ruled out before chemical "sensitivity" is proposed. Also, several questions on the toxicology of the chemical exposure must be addressed. Although temporality may be apparent (toxicity followed exposure), the time frame for the appearance of symptoms must be appropriate to the exposure conditions and chemical(s) involved. The chemical(s) must have known or reasonably inferred properties to cause the claimed effect. The dose(s) received must be adequate to effect a response (dose-response characteristics). Alternate causation must be evaluated thoroughly, that is, are there other more logical explanations for the symptoms? In contrast to single-chemical exposures, exposure to mixtures of chemicals, as commonly found in sick buildings, is very difficult to evaluate. However, a rational, scientific approach to cause-and-effect questions will help avoid erroneous and subjective decision making.