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Submitted for reprint by Paul Michalko, CIH, CSP, ARM, AASCIF Safety & Health Committee; written by Beth Mohr, Ph. D., CIH, Industrial Hygiene Consultant, California State Compensation Insurance Fund
Asthma has been getting a lot of press lately. But many people are not aware that exposure to some air contaminants in the workplace can actually cause asthma. Animal handlers, bakers, carpenters, electronic workers, healthcare workers, hairdressers, janitors, and welders are just some of the many workers that may be at risk.
Asthma is a respiratory disease. Symptoms include shortness of breath, chest tightness, wheezing, and cough. Occupational asthma occurs when a previously healthy (asymptomatic) individual develops asthma as a result of exposure to air contaminants at the workplace.
Occupational asthma typically develops after months or years of repeated exposure to a substance without any symptoms. After that time, the worker may become allergic, or sensitized, to the causative agent. Once sensitized, even a low exposure to the responsible substance can trigger an asthma attack.
Exposure to a trigger causes inflammation, excessive mucous, and tightening of the muscles in the airway. This reaction can make breathing difficult and, in severe cases, can be life-threatening.
An asthma attack may occur at work, shortly after exposure to a trigger, or the symptoms may be delayed, appearing only after the employee leaves work. When this happens, the person might not realize that something at work is triggering the asthma.
Substances that cause asthma are called asthmagens. There are hundreds of known occupational asthmagens—and the list is growing. Asthmagens can be chemicals, pharmaceuticals, or substances of biological origin. Examples of common asthmagens include isocyanates, formaldehyde, latex, glutaraldehyde, animal dander, and certain wood dusts.
Occupational asthma may become permanent even if the workplace exposure stops. To reduce this risk, it is important to diagnose the condition and prevent future exposures as soon as possible.
To prevent occupational asthma, minimize exposure to asthmagens. It is best to replace asthmagens with less-hazardous substances whenever possible. Local exhaust ventilation and/or enclosures can also control exposures. Respirators can provide protection, but they must be properly selected and used correctly.
Reactive airways dysfunction syndrome, or RADS, is another, less-common asthmatic condition that can result from occupational exposure. RADS results from a single, high-concentration exposure to an irritant such as chlorine, glacial acetic acid, or sulfur dioxide. Symptoms occur within 24 hours of the exposure. To prevent high exposures that might result from a leak or spill, it is important to have a plan for safely handling these situations.
To learn more about occupational asthma, go to the site index on the OSHA Web site at www.osha.gov and look under "O."
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