With more plastic-based products on the market than ever before, concern about the work-related risks of the chemicals used to make them is increasing. One of these chemicals is styrene, a compound used extensively in plastic and rubber for cars, food packaging, boats, and many other products.

Scientific studies have linked work-related styrene exposure to asthma and an irreversible lung disease known as obliterative bronchiolitis. This rare lung disease causes scar tissue and inflammation in the small airways, which eventually makes it difficult to breathe. NIOSH recommends a styrene exposure limit of 50 ppm, or parts per million, over an 8-hour workday to prevent adverse health effects.

To understand whether work-related exposure to styrene increases the risk of asthma and obliterative bronchiolitis, NIOSH investigators analyzed 55 published studies and 2 additional unpublished case reports, according to their paper published in the American Journal of Industrial Medicine. They considered three types of studies, including those that reported individuals with lung disease, those that calculated death rates from lung diseases, and those that collected information from study participants at one point in time, known as cross-sectional studies. Overall, they found 10 cases of obliterative bronchiolitis and 8 cases of asthma, with each case having had substantial styrene exposure. Among the cross-sectional studies, 87% had evidence that styrene exposure was associated with lung disease, and half of the death-rate studies had evidence that styrene exposure was associated with death from lung disease. In addition, 75% of the asthma cases reviewed had abnormal results following inhalational challenges to styrene. These findings suggest a relationship between styrene exposure at work and developing asthma and obliterative bronchiolitis. Although they do not prove cause and effect, the findings underscore the need for further research into the risk of styrene exposure at work.

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