Study explores styrene exposure at work and cancer

Chemicals are used in manufacturing to make everything from food containers to your favorite pair of shoes. One such chemical is styrene, a colorless, strong-smelling liquid used to make plastics and rubber for these products and others, including insulation, fiberglass, pipes, vehicle parts, and carpet backing.

During the manufacturing process, chemical vapors contaminate the air. When workers breathe in this contaminated air, styrene exposure can occur. The known health effects of styrene exposure include changes in color vision, tiredness, dizziness, delayed reactions, and difficulty with concentration and balance. Less well known is whether styrene increases the risk of cancer, although it is “reasonably anticipated to be a human carcinogen,” according to the National Toxicology ProgramCdc-pdfExternal.

To further explore the relationship between work-related styrene exposure and cancer, NIOSH investigators compared styrene exposures to cancer deaths among 5,201 former workers in two boat-building facilities in Washington State. The facilities have since closed but, when operational, manufactured boats using styrene-containing materials. The investigators looked at all workers who had worked in one of the facilities for at least one day between January 1, 1959, and September 31, 1978.

A previous NIOSH study focused on this group of workers, but the current study extended the follow-up by five years, and included data on 418 additional deaths. Using publicly available information from the National Death Index, NIOSH investigators calculated death rates from cancers of the blood and lymphatic system, such as leukemia and lymphoma, and lung cancer among the workers. They then compared the cancer-related death rate among the workers to the rate found among the general population in Washington State. Additionally, the investigators used information from personnel records to estimate styrene exposure by length of employment and job type, and calculated the risk of cancer death related to this exposure.

The investigators focused on two types of cancers, leukemia and lung cancer. Researchers found the death rate from leukemia among these workers was comparable to the rate in the general population, according to the study published in the American Journal of Industrial MedicineExternal. However, workers in the boat-building facilities with longer tenure with more exposure to styrene did show a greater risk of leukemia when compared to shorter-term workers. On the other hand, the risk of dying from lung cancer did not appear to be associated with styrene exposure while working in the boat-building facilities.

Although this study suggests an association between styrene exposure and cancer, other studies of similar workers have been inconsistent. More research is needed to fully understand the relationship between work-related styrene exposure and cancer risk.