In situations, when there is a possibility that the symptoms could be associated with occupational or environmental exposures, it is necessary that the practitioner proceed with more thorough questioning. Questions such as products manufactured and place of employment should be included. The affected individual should describe the tasks performed at the workplace, agents handled, and the work conditions. To get more information about chemical exposures, practitioners can start by obtaining the generic names of agents that were used. The same can be achieved by asking the patient to bring in a label or a Material Safety Data Sheet (MSDS) that is the description provided by the manufacturer about the product’s generic name, ingredients used, known health hazards, and guidelines for safe handling. The MSDS varies in terms of completeness and accuracy. MSDS’s can be acquired from the manufacturer or the employer, and some of them can also be obtained from Internet sites (a reliable online source is the Vermont Safety Information Resources: siri.org). More information about the health effects associated with these toxins can be obtained through other sources, for instance, poison control centers (1-800-222-1222), agencies, consultants, and useful references.

After identifying what exactly is being handled, the next step would require practitioners to ascertain whether or not there are possibilities of actual exposure. For that, the patient should be able to explain how a substance is handled: The operating and cleanup practices that are followed; the protective measures that are taken; the type of ventilation and exhaust systems that are deployed; is a respirator required while working, and in that case, is a proper respirator provided to the worker, and is it used and maintained in a proper manner? The NIOSH website is a good source for obtaining information about respirators: www.cdc.gov/niosh/npptl/topics/respirators.

After this the focus should shift to the mode of entry: Is the substance inhaled? Does it enter the body while eating at the workplace? Does the substance come into contact with skin? Do workers use appropriate gloves or protective clothing to prevent skin absorption? Do other workers also get exposed? Do other workers experience any symptoms?

It also helps to know if the individual exposed may be especially susceptible to the exposure. For instance, if an individual with renal disease faces lead exposure at acceptable (regulatory) air levels, he/she may experience higher than expected levels of lead accumulation due to the reduced ability to remove it through the kidneys. In case of a pregnant woman who is exposed to harmful substances such as carbon monoxide or lead, the level of exposure may not be harmful for her, but can be dangerous for the developing fetus, which is more susceptible to the adverse effects.

Certain exposures can also take place inside or outside of the home. Exposures within the home can occur due to use of specific household chemicals, home remodeling, indulgence in certain hobbies, or when contaminated work clothing is brought home. Household products databases can be found on the Internet, which provide information about health effects of more than 4000 consumer brands (https://www.loc.gov/item/lcwaN0003801/).

Contamination can occur at home, and also in the surrounding air, soil and water due to nearby commercial businesses, industrial plants, dump sites, or through natural disasters such as flooding, hurricanes, or earthquakes. Based on complaints described by the patient, practitioners may be required to inquire about heating and cooling systems, home insulation, pesticide use, home cleaning agents, water leaks, water supply, air pollution, recent renovations, hazardous waste contamination, specific hobbies, floods, spills, or any other exposure. In case home and neighborhood exposures have been confirmed, it may be necessary to examine the possibility of exposure in children.