Large, New Study Finds ‘No Credible Evidence’ That Styrene Exposure Increases Human Cancer Risk

WASHINGTON--(BUSINESS WIRE)--A newly published study of nearly 16,000 styrene-exposed workers finds no credible evidence that such exposure increases the risk from cancers of the lymphatic and hematopoietic tissue, pancreas or lung. The study, “Cancer Mortality of Workers Exposed to Styrene in the US Reinforced Plastics and Composite Industry,”¹ is available online and has been published in the peer-reviewed journal Epidemiology’s March issue.

“Cancer Mortality of Workers Exposed to Styrene in the US Reinforced Plastics and Composite Industry”

“These findings, which are based on 60 years worth of epidemiology data on cancer risks associated with workers exposed to relatively high levels of styrene, completely undercut the U.S. National Toxicology Program’s listing of styrene as ‘reasonably anticipated to be a human carcinogen’ in its 12^th Report on Carcinogens,” says Jack Snyder, executive director of the Styrene Information and Research Center (SIRC), which supported² the study.

The authors examined mortality rates associated with cumulative exposure, duration of exposure, peak exposures, average exposure and time since the first exposure of styrene, and concluded: “[W]e found no increased mortality from lymphatic and hematopoietic tissue cancers overall or in any sub-diagnoses including non-Hodgkin lymphoma, Hodgkin lymphoma, multiple myeloma or leukemia in this highly exposed group of styrene workers. Further, no exposure response was associated with cumulative daily peak exposure or number of peak exposures…

“Lung cancer rates, while greater than expected, appeared to be unrelated to styrene exposure and more likely attributable to smoking. In this large study with relatively high styrene exposure, we find no credible evidence that styrene exposure increases risk from cancers of the lymphatic and hematopoietic tissue, pancreas, or lung.”

“This updated analysis substantially adds to the evidence that indicates a lack of association between styrene exposure and cancer,” says Julie Goodman Ph.D., DABT, a toxicologist with Gradient. Goodman co-authored a recent weight-of-evidence analysis of styrene research, concluding that studies in humans, and particularly workers with high styrene exposures, show no consistent increase in death from any type of cancer.

This new report adds 19 years of follow-up mortality data to a study of workers in the reinforced plastics industry published originally in 1990³ and updated in 1994⁴. Studies involving workers in the reinforced plastics industry are considered the most informative because styrene exposure typically is higher than in other industries where styrene is used, confounding from other potentially carcinogenic exposures is uncommon, and the study populations are large.

Find out more about the Styrene Information and Research Center by visiting the SIRC website, www.styrene.org.

¹ Collins, JJ, Bodner, KM, Bus, JS. Cancer Mortality of Workers Exposed to Styrene in the US Reinforced Plastics and Composite Industry. Epidemiology, March 2013, 24(2), 195-203. http://journals.lww.com/epidem/Abstract/2013/03000/Cancer_Mortality_of_Workers_Exposed_to_Styrene_in.5.aspx

² The Styrene Information and Research Center (www.styrene.org) did not contribute to the design or conduct of the study or to the writing or submission of the manuscript.

³ Wong O. A Cohort Mortality Study and a Case-Control Study of Workers Potentially Exposed to Styrene in the Reinforced Plastics and Composites Industry. Br J Ind Med., 1990.

⁴ Wong O, Trent LS, Whorton MD. An Updated Cohort Mortality Study of Workers Exposed to Styrene in the Reinforced Plastics and Composites Industry. Occup Environ Med. 1994.