Special session-TILT: Identifying Initiators and Triggers of Chemical Intolerance?


Typically, the indoor environment is polluted with low-level Volatiles Organic Compounds (VOCs). Although the indoor VOCs concentrations are below guidelines, some individuals are capable of developping chemical intolerance (CI). For example, a quarter of the american population suffers from CI with only 5% being reported by a doctor (#762), and females seem more prone to develop CI (#769). Yet, the mechanism behinds CI are not well understood.

To better understand this phenomena, the group of researchers used the Toxicant-Induced Loss of Tolerance (TILT) concept.  They describe TILT in two stages: initiation and triggering (#765). Phase I, or Initiation, occurs when the person is repeatidly exposed to a low-level of chemical or to a temporary but extremly high concentration of chemical. Then, the person becomes intolerant to substances they were not intolerant to earlier. They experience symptoms such as: fatigue, headache, rash, weakness, mood changes, breahting difficulties, concentration difficulties, gastrointestinal and skin symptoms (#765, #762 and #769). In Phase II, or triggering, the person reacts to any kind of exposure in a much higher magnitude that hampers normal living (#765 and #769).


The group of researchers have focuses on determining the sources at the origin of TILT and have developped two health-based questionnaires to help individual self-assessment but also professional practionners to determine whether an individual suffered from TILT or not.


They analysed events to determine the sources of TILT: one building renovation (EPA headquartesrs in 1980), Gulf War, World Trade Center (WTC) tragedy, exposure to airplane exhaust, mold, pest control and surgical implants (#765). Their findings point synthetic organic chemicals (e.g. pesticides, nerve agents, anti-nerve agent pills, lubricants and additives, mixed indoor VOCs, and WTC dust) and combustion produts (consist of a complex mixture of organic and inorganic gases and particles) as potentially important initiator of TILT (#765).

Both the Quick Environmental Exposure and Sensitivity Inventory (QEESI) and the Brief Environmental Exposure and Sensitivity Inventory (BREESI) questionnairs are available to assess the presence of CI. QEESI is a validated test used worldwide to identify CI answering through 50 questions (#762). QEESI uses a 0 to 10 severity rating scales for symptoms, chemical and other exposures, and life impact  (#769). The use of QEESI has increase the awareness of CI, 8 to 33% of the population was reported to suffer from CI (#762).  Recently, a briefer version of QEESI was proposed, the Brief Environmental Exposure and Sensitivity Inventory (BREESI), this three-question test is a pre-assessment tool to help determine whether an individual should take the entire QEESI (#762 and #769).

The researchers assessed the positive and negative correlation between the BREESI and QEESI (#762). 200 individuals took both the BREESI and QEESI. 97% of the individuals who answered YES to the tree-question BREESI questionnaire also srored with the QEESI (#762). The accuracy statistic for an individual to be correctly classified is of 98.6% (#762). the researcher recommended that each individuals who answer yes to at least one of the three-question in the BREESI also take the QEESI (#762).

Conference Dinner at the Academy of Natural Sciences.

In another study, the researchers selected 50 individual suffering from CI to participe in a more extensive survey (#771). The study consisted of three phases: indoor air quality assessments, biological sampling (including allergy test) and QEESI test. The results of the QEESI were compared with the chemical and biological data. Formaldehyde exposure(e.g. in recently constructed houses) was identified as a prepoderant factor in severe case of CI. One of the participant who suffer from severe TILTed symptoms originating from unusually high level of chemicals present in the attached garage (scented household cleaning products, gasoline, paints, and solvents) was adviced to relocate these pollutants into an outdoor premises, after which the symptoms decreased.


The researchers pointed out formaldehyde, synthetic organic coumpounds and combustion products as preponderant trigger of CI. They demonstrate the importance of detecting CI using tools like the BREESI and QEESI questionnaires.

Better understanding the origins and mechanism of CI will help minimize exposure. this research also highlight the importance of minimizing indoor VOCs exposure.   


Paper ID #761

Using the QEESI symptom star to document Chemical Intolerance: A case study

Carl Grimes

Paper ID #762

Validated Clinical and Epidemiological Approaches for Assessing Chemical Intolerance: The QEESI and BREESI

Raymond F Palmer, Roger Perales, Rudy Rincon, Claudia S Miller, Carl Grimes

Paper ID #765

what initiates Chemical Intolerance?

Shahir Masri, Claudia Miller

Paper ID #767

Environmental House Calls (EHC): Procedures and Methods in a Study to Identify Triggers for Chemical Intolerance

Roger Perales, Rudy Rincon, Raymond F Palmer, Claudia S Miller

Paper ID #769

Indoor Air, Chemical Intolerance, and toxicant-Induced Loss of tolerance (TILT)

Claudia S. Miller, Ray Palmer, Roger Perales, Rudy Rincon

Paper ID #771

Environmental House Calls (EHCs): Findings from the Toxicant-Induced Loss of Tolerance (TILT) Research Project.

Rudy Rincon, Raymond F Palmer, Roger Perales, Claudia S Miller

Castagnoli Emmanuelle

Emmanuelle Castagnoli

Master of Chemistry, Aalto University