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Ashford urges research on chemical sensitivity

An MIT researcher who helped bring the problem of multiple chemical sensitivity (MCS) to national attention several years ago will outline his recommendations for pushing the dialogue on MCS beyond the debate over authenticity and into the realm of scientific research and social policy.

Professor Nicholas A. Ashford, who in 1991 co-authored the first definitive report on low-level chemical sensitivity -- believed by many to be the basis for conditions such as Gulf War syndrome and sick-building syndrome -- will speak at 1:15pm today at the American Chemical Society's national meeting at the Marriott Copley Hotel in Boston.

Eight years ago, Dr. Ashford and co-author Claudia Miller, MD, of the University of Texas investigated illnesses characterized by low-level sensitivity to chemicals -- which they now refer to as toxicant-induced loss of tolerance (TILT) diseases. According to this theory, TILT diseases occur in two steps: an initiating exposure to a single large dose or many repeated smaller doses of a chemical, followed by increased sensitivity to very small amounts of many different chemicals encountered in daily life.

"The initiating event or series of events in TILT primes the body to be exquisitely sensitive to a large number of particular chemicals," said Dr. Ashford, who is professor of technology and policy in MIT's Center for Technology, Policy and Industrial Development, as well as an adjunct faculty member at both the Harvard and Boston University Schools of Public Health. "Once primed, the body responds at levels much lower than normal to very common chemicals, like diesel exhaust or common organic solvents."

Afflicted people are often unable to work or live normally as they become debilitated by symptoms of rhinitis, asthma, nausea, muscle aches, cardiac problems and even cognitive difficulties. Many see more than a dozen physicians in seeking a diagnosis and treatment for their difficulties.

Professor Ashford believes that as many as 15-20 percent of people living in urban areas could be significantly affected by TILT, and that attention deficit hyperactivity disorder in children may very well be a TILT disease stemming from pesticide application in schools. "But we don't know this," he added. "It's a theory."


In order to sift out answers from the theories, Professor Ashford recommends that research programs be undertaken in special contaminant-free, environmental medical units and that double-blind, placebo-controlled tests be used to determine if some people really do respond to unusually low levels of common chemicals or "if this a figment of their imagination," he said. Other research is needed to determine the origin of any increased sensitivity.

Additionally, he recommends that questions of social policy, such as the issue of special accommodations for patients by employers and landlords, be addressed at the national level so that a consistent policy based on scientific research may be developed.

For instance, the Social Security Administration recognizes Gulf War syndrome as a disability. But the Department of Defense has not yet accepted that events in the Gulf War initiated the disease. This sort of confusion about diagnosis and cause make it impossible for most people to receive adequate treatment.


When MCS problems first came to light, such as in groups of people exposed to chemicals in airtight buildings, they were often labeled as mass psychogenic illness and dismissed. But thanks in part to Chemical Exposures: Low Levels and High Stakes (John Wiley and Sons, 1991 and 1998), by Drs. Ashford and Miller, the strong possibility of a physical basis for the troubling array of symptoms is now widely recognized.

"Even if we don't know the exact origin or combination of physical and psychological basis of this class of diseases, if there are a lot of people affected, shouldn't we find a way of helping them?" said Professor Ashford, who holds a PhD in chemistry as well as a law degree.

Instead, physicians often prescribe psychiatric care for people with TILT diseases rather than search for an underlying organic disorder.

People with TILT diseases present "every symptom in the book," said Professor Ashford, and because they are sensitive to everyday chemicals at levels that may be one thousand times lower than levels that appear to affect most people, it "violates the tenets of traditional toxicology. Moreover, the time lag between the first and subsequent stages of disease can obscure the connection between exposures and ultimate disease.

"It just doesn't follow the usual medical model. You learn in medical school that the more symptoms people present, the more you should look for a psychogenic origin. But if the brain has been damaged by the initiating chemical exposure -- as some people believe -- then people will behave in strange ways. Their neurological, endocrinological and immunological systems may have been severely impaired."

The most important recent research on the condition has focused on people in three groups: those exposed to organophosphate pesticides, those exposed to remodeling, and Gulf War veterans who returned ill. According to Professor Ashford, a fourth possible study group could be women who have had silicone breast implants.

While the reported symptoms of all these people are numerous, the similarities among members within groups are striking. For instance, people who share an exposure to organophosphate pesticides as their initiating event provide the same ranking of the severity of their most common symptoms. And they tend to rank all symptoms more severely than do people in the group whose initiating event was exposure to chemicals during remodeling. Gulf War syndrome symptoms tend to fall between the other two groups in terms of severity.

"These findings are what one would expect in diseases with an organic basis. If this were a head problem, the rankings would be more equal among the three groups," said Professor Ashford.

He first began studying the problem of increased chemical sensitivity at the request of the New Jersey state government in 1988, which allocated a two-weeks' consulting budget for a study that in the end took him and a co-author (Dr. Miller) two years to complete.

"We just had no idea initially how complex and widespread these diseases were," said Professor Ashford. That report was published as the first edition of Chemical Exposures and won the World Health Organization's Macedo Award.

The authors prepared the second edition, which was published in February, without funding. It includes about 200 new pages, leaving the material from the first edition virtually untouched. Professor Ashford considers this fact -- that developments since 1991 did not require changes to the original theory -- to be a testimonial to the first edition's accuracy.

"We were right on the money the first time. The earlier material didn't need to be corrected, so we simply added a considerable amount of updated material," said Professor Ashford, whose first book, Crisis in the Workplace: Occupational Disease and Injury (MIT Press, 1976) is still in print more than 20 years after its publication.

"Of all the things I've worked on, this was the most difficult," he said. "It's controversial, so you can't overstate the evidence. But you can't ignore it either. You've got to toe a line which is unbelievably difficult."

A version of this article appeared in MIT Tech Talk on September 26, 1998.

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