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Multiple Chemical Sensitivities

Multiple Chemical Sensitivities (MCS) is a highly controversial issue. In theory, MCS is an adverse physical reaction to low levels of many common chemicals. Chemical sensitivity is generally accepted as a reaction to chemicals but debate continues as to whether MCS is classifiable as an illness. There are a number of synonyms for MCS, including 20th century disease, environmental illness, total allergy syndrome, idiopathic environmental illness, and chemical AIDS.

Proposed theories to explain the cause of MCS include allergy, dysfunction of the immune system, neurobiological sensitization, and various psychological theories. There is insufficient scientific evidence to confirm a relationship between any of these possible causes and symptoms. Due to the lack of definite information an evaluation must be performed by a physician knowledgeable of the symptoms of this condition.

Hazard Recognition

Multiple chemical sensitivity (MCS) patients often report non-specific symptoms from exposure to low-levels of chemical, biological, or physical agents. There seems to be no single stimuli or predictor of reactions. The following references aid in recognizing the illnesses and hazards associated with MCS.

  • Multiple Chemical Sensitivity [212 KB PDF, 3 pages]. The Ohio State University Extension Fact Sheet CDFS-192-08, (2008). Presents a definition of MCS, describes some of the difficulties involved in identifying and defining the disorder, and provides recommendations for reducing chemical exposures.

Evaluation and Management

Limited information is available on effective control measures, exposure assessments, and regulations dealing with multiple chemical sensitivities (MCS). However, OSHA does regulate exposures to specific chemical hazards. For additional information, see OSHA's Safety and Health Topics Pages for Hazardous and Toxic Substances and Ventilation.

Many physicians are uncertain how to approach the evaluation and care of persons who have multiple symptoms attributed to low-level chemical exposure. The identification of MCS is based largely on the patient's description of the symptoms and the relationship of these symptoms to environmental exposures. The following references provide information about the clinical evaluation process and management of MCS.

  • A Report on Multiple Chemical Sensitivity (MCS). Interagency Workgroup on Multiple Chemical Sensitivity, (1998, August 24). Provides a public health evaluation of the extent and nature of MCS and recommends future actions for federal agencies to consider.

  • Case Studies in Environmental Medicine: Taking An Exposure History. Agency for Toxic Substances and Disease Registry (ATSDR), (2008, May 12). Also available as a 473 KB PDF, 65 pages. Helps increase the primary care providers knowledge of hazardous substances in the environment and to promote the adoption of medical practices that aid in the evaluation and care of potentially exposed patients.
  • Magill, M. and A. Suruda. "Multiple Chemical Sensitivity Syndrome." American Family Physician 58(3):721-728. (1998, September 1). Provides a description of MCS and its symptoms. It also presents recommendations for physicians' evaluation and management of the syndrome.

Additional Information

Related Safety and Health Topics Pages

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