The following statements have been prepared by each of
the agencies represented in the workgroup. They describe their past and current activities
related to low-level chemical sensitivity research and any future initiatives. It is hoped
that these overviews will help in coordinating plans and further actions. The
presentations also show the range of federal activities with regard to MCS.
Agency for Toxic Substances
and Disease Registry
ATSDR, under its authorities in the Comprehensive
Environmental Response, Compensation, and Liability Act of 1980 (CERCLA), has maintained
interest for several years in issues surrounding sensitivity to low levels of chemicals
because these kinds of exposures can occur in populations who live near hazardous waste
sites, which are the focus of CERCLA. Given the need for additional scientific research,
ATSDR provided financial support for two conferences focused on MCS: the first meeting was
sponsored by the National Academy of Sciences (NAS) in March 1991, and the second was
sponsored by the Association of Occupational and Environmental Clinics (AOEC) in September
In fiscal year 1993, Congress appropriated $250,000 to ATSDR for "[c]hemical
sensitivity and low-level chemical and environmental exposure workshops." The first
effort under this mandate was to convene an expert panel in April 1993. Out of the
deliberations of this panel came a number of recommendations that resulted in the
following actions: (1) a conference on Low Level Exposure to Chemicals and Neurobiologic
Sensitivity, Baltimore, Maryland, April 1994; (2) publication of the proceedings from that
conference, as well as an additional publication containing the proceedings from three
federally sponsored conferences on MCS (i.e., the NRC 1991, AOEC 1991, and ATSDR 1994
conferences); and (3) an award to the California Department of Health Services "[t]o
develop a controlled, scientifically acceptable research design which will test the
hypothesis that there is a group of individuals with physiologically based susceptibility
to low levels of chemical exposure."
Throughout these efforts, ATSDR has served as a conduit of
information about the issues surrounding MCS and has encouraged clinical and other
research to add to the knowledge base concerning low-level chemical sensitivity. ATSDR has
no on-going or planned research activities specific to MCS.
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As the employer of more than 100,000 federal and
contractor employees, the Department of Energy (DOE) is interested in developments in MCS.
An informal sampling of the Department's occupational health clinics revealed occasions of
workers complaining of possible MCS symptoms. Some of the clinic medical directors
suggested that MCS may become a larger concern for DOE and would value guidance from the
workgroup. There are currently no uniform diagnostic criteria or treatment protocols in
use at DOE sites.
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The Department of Veterans Affairs (DVA) has funded three
Environmental Hazards Centers for the purpose of conducting research on environmental
health and toxicology related to military service. At this time, these centers are all
involved in research on Persian Gulf veterans' illnesses. Two of the centers include
research involving MCS in their research protocols.
At the Boston Environmental Hazards Center, the physical and psychological health of a
cohort of Gulf War veterans has been followed longitudinally since their return from the
Persian Gulf. A subset of these veterans is being examined intensively with protocols
addressing MCS and other conditions; diagnoses of MCS, based on the Cullen criteria, are
being made as appropriate. Detailed studies of those diagnosed with MCS include
psychiatric status, neuropsychological function, symptom reports, occupational and
economic outcomes, pulmonary function, neurologic status (central nervous system [CNS],
peripheral nervous system [PNS], autonomic nervous system [ANS] with sophisticated
neuroimaging and neuropsychological assessment), and evaluation of stressors (i.e.,
social, war trauma, and/or exposure to environmental hazards).
At the East Orange Environmental Hazards Center, an epidemiologic study of Persian Gulf
Registry and nonregistry veterans is being conducted that will allow diagnosis of MCS,
CFS, and other disorders. A cross-sectional study is being done of several categories of
veterans: those with MCS but without CFS, those with CFS without MCS, and those having
both CFS and MCS. Control subjects are being tested for viral/immunologic measures;
psychiatric, psychological, and neuropsychological function, and autonomic deregulation.
An experimental study is also planned at East Orange in which 40 MCS subjects will be
exposed to two stressors (i.e., exercise and exposure to phenyl ethyl alcohol) and will
undergo several preexposure and postexposure measures, including assessment of symptoms,
neurobehavioral performance, nasal lavage cellularity, RNA levels of cytokine gene
expression, and autonomic reactivity.
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National Center for
Environmental Health, CDC
CDC's National Center for Environmental Health (NCEH) was
established to promote health and quality of life by preventing and controlling disease,
injury, and disability associated with the interactions between people and their
environment outside the workplace. The impact of its programs is amplified through close
interaction with public health departments in every state and with many public, private,
and international organizations. Its major activities include biomonitoring for
environmental toxicants, lead poisoning surveillance and prevention, birth defects
surveillance and prevention, and exigent public health investigations where environmental
exposures may be involved.
NCEH does not have any programs directly devoted to MCS; however, a number of its
activities are relevant to the issues surrounding MCS. Through its division of
Environmental Health Laboratory Sciences (EHLS), NCEH has a unique leadership role in
measuring more than 200 toxicants in human biologic samples. Analyses of samples from
large population studies have established the extent of exposure in the U.S. population to
volatile organic compounds, pesticides, halogenated aromatic compounds (e.g., PCBs), toxic
metals (e.g., lead and cadmium), and environmental tobacco smoke. This information helps
to clarify relationships between exposures to toxicants and human health effects.
NCEH has also addressed the use of laboratory tests as biomarkers of susceptibility and
health effects, concentrating on target organs such as the liver, kidney, and immune
system. NCEH provides national reference laboratory capability for tests of immune status
and function, including lymphocyte phenotyping, serum mediator measurements, and various
assays of actual immune function. Standardization of these tests for immune status has
been a particular focus at NCEH, whose investigators have collaborated with NAS, ATSDR,
and AOEC to establish guidelines for the proper use of these tests and apply them to
public health studies.
A number of epidemiologic investigations conducted by NCEH have relevance to questions
of chemical sensitivities. Epidemiologists in the Division of Environmental Health Hazards
and Health Effects have investigated adverse health effects associated with tryptophan
ingestion, inhalation of fuels and other air pollutants, and fetal alcohol exposure. A
community-based program in asthma prevention will explore risk factors and intervention
effectiveness for this increasingly important cause of morbidity and mortality. At
present, there is no specific funding or legislative mandate within NCEH in the area of
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National Institute of
Environmental Health Sciences, NIH
The mission of NIH's NIEHS is to reduce the burden of
human illness and dysfunction from environmental exposures by understanding the
interrelationship between exposure, individual susceptibility, and time. NIEHS has
provided research support to studies related to MCS and to areas of research associated
with MCS outcomes.
Research activities funded by NIEHS related to chemical sensitivity focus primarily on
(1) exposure and organ and system toxicology and (2) genetic susceptibility of exposure.
It appears that environmental agents can trigger a variety of disorders in susceptible
persons. Some susceptible persons apparently respond to extremely low levels of chemicals
in the environment by expressing multiple symptoms in one or more organ systems,
frequently involving the central nervous system. Such chemical exposures and symptoms
appear to be associated with proximity to hazardous waste sites, other community
exposures, indoor air pollution, and industrial activities. Pesticides and solvents are
the two major classes of chemicals most frequently reported by patients reporting low
level sensitivities as having initiated their problems.
NIEHS has also supported a number of workshops and meetings concerning MCS. In
September 1995, the NIEHS Superfund Hazardous Substances Basic Research and Training
Program supported a workshop in Princeton, New Jersey, entitled Multiple Chemical
Sensitivities: Controlled Exposure Studies. This workshop brought together a number of
leading investigators in the field to assist NIEHS in developing new and innovative
research ideas to better understand MCS. The overall objective of the meeting was to
develop experimental approaches for testing the relationship between chemical exposures
and the symptomatology expressed by patients with chemical sensitivities.
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National Institute for
Occupational Safety and Health, CDC
CDC's National Institute for Occupational Safety and
Health (NIOSH) receives hundreds of requests annually for information on MCS. An estimated
200-400 requests are received through NIOSH's toll-free telephone number. NIOSH sends
information about MCS to these requestors.
NIOSH conducts workplace health hazard evaluations at the request of workers,
employers, and government agencies. A small number of requests have included mention of
MCS in combination with a variety of other concerns.
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U.S. Environmental Protection
EPA has occasionally received reports from individuals of
symptoms that they attributed to chemical sensitivity subsequent to pesticide or other
chemical exposures. Some EPA employees have also reported complaints of chemical
sensitivity that they attributed to workplace or other exposures to various substances.
EPA is interested in understanding the scientific basis for the development of effects
following exposures at much lower levels than average, the exposures that produce such
effects, and the quantitative relationships between them.
Research activities related to chemical sensitivity are being conducted by EPA as part
of the agency's health research program on indoor air pollutants. EPA's statutory
authority for indoor-air issues and problems enables the agency to engage in research and
information dissemination rather than regulation, enforcement, or other control
activities. In the indoor air health research program, research is being performed to (1)
understand the relationship between exposure to and effects of selected biocontaminants;
(2) develop methods and understand the risks posed by low levels and mixtures of indoor
organic vapors; and (3) understand the dimensions and characteristics of susceptible
populations, including those who report multiple chemical sensitivity. The goals of the
research on susceptible populations are to identify such populations and evaluate the
determinants of susceptibility, with current emphasis on clinically characterizing those
persons who report having chemical sensitivity.
Part of the difficulty with conducting MCS research is identifying objective,
quantifiable indicators for classifying research subjects in order to study their
conditions in greater depth. An NAS workshop was initiated and funded by EPA's Indoor Air
Division to identify research needs for MCS. Scientists from EPA's National Health and
Environmental Effects Research Laboratory (NHEERL) also participated in the workshop, from
which emerged a recommendation that careful clinical characterizations be done on persons
reporting MCS to identify cases for additional study. In response to this recommendation,
NHEERL scientists developed a protocol and initiated a pilot study to evaluate persons
reporting MCS symptomatology on the basis of exposure history and symptoms; medical
history and examination; psychiatric evaluation; and a profile of clinical medical,
psychological, and physiologic parameters and test results. The purpose of this pilot
study was to generate hypotheses that are feasible to test. Data were collected over an
extended period of time on a small group of subjects who self-reported chemical
sensitivity. NHEERL has not yet reported its findings.
In addition, EPA scientists are communicating and coordinating with other organizations
involved in research on MCS. Besides cosponsoring and participating in the NAS workshop,
EPA has coordinated with ATSDR to ensure mutual understanding of both agencies' efforts on
MCS. NHEERL scientists have made invited presentations about MCS to the Toxicology Forum
(Summer 1993) and the American College of Allergy and Immunology (Fall 1993). EPA
participated in the ATSDR-sponsored MCS meetings held in 1993 and 1994. NHEERL is actively
pursuing collaborative exchanges of information with investigators from the academic
community (e.g., the University of Medicine and Dentistry of New Jersey and Yale
University). NHEERL scientists have also published articles addressing MCS-related
research issues (Dyer and Sexton, 1996; Dyer, 1997).
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Summary of Federal Actions