My interest in the connection between chemicals and health began when I was a high school student volunteering in a neighborhood that was built on top of an abandoned landfill in Medellin, Colombia. My position involved playing with and feeding neighborhood children, selling inexpensive used clothing, and teaching adults to read and write. It also allowed me to observe their deplorable life conditions—I could see decomposing garbage peeking through the top soil between houses, large gas plumes sporadically venting from the ground, and brown water running from kitchen faucets. I could not escape the repulsive odors creeping around every corner.
Even though I was young, I knew that the environment in which they lived made them sick. Mothers were always fatigued and coughing, while their kids looked malnourished and had skin rashes, infected wounds, and sometimes deformities. I knew then that I would devote my professional life to understanding the relationship between chemicals and health—a desire to prevent the suffering that stems from living in toxic environments pushed me to pursue scientific research. Many years later, I now study the health effects of chemical exposures in our environment, focusing on the places where we work.
We spend up to 90% of our time indoors: inside our homes, schools, and workplaces. For most of us, time spent indoors exposes us to a wide variety of chemicals, especially at work, where we are often in proximity to substances associated with day-to-day responsibilities associated with manufacturing, construction, or practicing medicine.
Even if a job doesn’t require working directly with chemicals, we may be exposed simply by spending time in areas where the chemicals are stored. Plus, we are exposed to chemicals in the materials used to construct and furnish the buildings in which we work and live. Some office or home furniture and flooring, for example, may emit low levels of formaldehyde, an irritant and sensitizer, which we may come into contact with daily.
For the most part, we are exposed to very small concentrations to the chemicals we come into contact with, and most of us do not perceive an acute reaction. However, some people develop an allergy that can lead to what we call a chemical sensitivity in my field. Sensitizers are the chemicals that are known to cause a negative reaction involving the immune system. Sensitization is the process by which a person becomes increasingly allergic to a sensitizer through repeated exposure.
The substance may cause a mild response during the first few exposures but, as the allergy develops, the response can become worse with subsequent exposures. Eventually, even short exposures to low concentrations can cause very severe reactions. People with chemical sensitivities may experience symptoms such as skin rashes, asthma, and other respiratory issues (Kimber et al. 2002 and 2011, HSE 2015a).
The implications for chemical sensitivities can be devastating to a person’s livelihood. Imagine, for example, what happens when a metal worker becomes sensitized to nickel, or a painter becomes sensitized to epoxy resins found in some paints. If symptoms improve only after reducing exposure to the chemical, one may need to find a different job or profession (HSE 2015b,c). The transition into a new career can be extremely stressful and disruptive.
It’s not only chemicals that can become sensitizers—the workplace can also expose us to other substances that can lead to sensitization. For example, hairdressers can become sensitized to latex in gloves, bakers to flour dust, and construction workers to wood dust. One of the most challenging aspects of doing research in this field is that we are rarely exposed to only one chemical or other sensitizer at a time. If this were the case, it would be relatively easy to isolate a single substance that could be at the heart of health issues that arise on site. But the nature of our indoor environment often exposes us to a multitude of sensitizers—sometimes all at once, sometimes over time, and sometimes both.
Even still, most of the research on chemical sensitivities focuses on single chemical exposures.
Through my doctoral and post-doctoral research I came to understand the challenges to preventing chemical sensitization. I interviewed many people in the automotive spray paint industry, including painters, business owners, trainers, and industry association folks who used isocyanate base coatings in their profession. I was shocked when every person I talked with knew of at least one person who had been affected by isocyanates. Some reported that their colleagues had changed work responsibilities and, more often than not, ended up doing office work instead of spray painting. I also learned about several extreme cases that resulted in severe reactions if the individual sensitized to isocyanates got too close to an auto body shop.
Later on, through my work with the National Institute for Occupational Health (NIOSH), I encountered many individuals who were highly sensitive to chemicals in their workplace, even when exposed to levels well below those that would be enforceable by regulations. In some cases, my team and I were able to provide recommendations to help with their health concerns, especially in cases where there was a clear relationship between a particular chemical exposure and health symptom. However, in most cases we were not able to help, especially when only one or two individuals reported nonspecific health symptoms. Help became even more challenging to provide when we were unable to determine if the health concerns were exclusively work-related or were also related to home, hobbies, or previous work. In many cases, those with chemical sensitivities would endure high levels of stress because their concerns were not often appropriately addressed. Many people in this situation would take long leaves of absence and eventually resign.
We need a stronger research base to better respond to the needs of individuals who are allergic to multiple substances in their environment. I am drawn to this research for the thrill of helping those who suffer by learning more about the causes behind their sensitivities, and also helping to prevent and alleviate their symptoms.
If you deal with substances at work and are unsure if you are exposed to known sensitizers, you first need to identify the chemicals you encounter. You can start by obtaining the safety data sheet and looking up the chemical ingredients at the NIOSH Pocket Guide to Chemical Hazards and check if “sensitization” is listed under symptoms.
If you think you are sensitized to a chemical or substance at your work, talk to your supervisor and work health provider for assistance.
HSE (2015a). Examples of skin irritants and sensitisers, together with occupations where they occur. http://www.hse.gov.uk/skin/professional/causes/agentstable1.htm. Accessed December 9, 2015.
HSE (2015b). Asthma. http://www.hse.gov.uk/asthma/index.htm. Accessed December 9, 2015.
HSE (2015c). Spray Painter and Isocyanate. http://www.hse.gov.uk/asthma/isocyanates.htm
Kimber I, Basketter DA, Gerberick GF, Dearman RJ. Allergic contact dermatitis. Int Immunopharmacol. 2002 Feb;2(2-3):201-11.
Kimber I, Basketter DA, Gerberick GF, Ryan CA, Dearman RJ. Chemical allergy: translating biology into hazard characterization. Toxicol Sci. 2011 Mar;120 Suppl 1:S238-68.
NIOSH (2015). Skin Exposures & Effects. Skin Notation (Sk) Profiles. http://www.cdc.gov/niosh/topics/skin/skin-notation_profiles.html. Accessed December 9, 2015.