Formaldehyde Exposure May Increase Risk of Blood and Lymphatic Cancers
Industrial workers who are exposed to formaldehyde may be at an increased risk of dying from blood and lymphatic cancers, particularly myeloid leukemia but also Hodgkin’s lymphoma and multiple myeloma, according to the results of a study published in the Journal of the National Cancer Institute.
Formaldehyde is a chemical that is widely used in industrial plants as a preservative or disinfectant. It has been classified as a carcinogen because of its association with nasopharyngeal cancer. Furthermore, it has been shown that the risk of leukemia increases as peak exposure to formaldehyde increases.
The National Cancer Institute’s formaldehyde cohort includes a group of 25,619 workers who were employed in one of 10 industrial plants before 1966. The plants either manufactured formaldehyde or used it. The original study included deaths through 1979. The study was then extended to include deaths from 1980 to 1994. Now researchers have extended this study a third time to include deaths through 2004.
The researchers evaluated peak exposure, average intensity, and cumulative exposure. For each job, they estimated the continuous eight-hour, time-weighted average formaldehyde intensity, referred to as TWA8. This exposure was expressed in parts per million (ppm) and divided into categories: 0-.5 ppm, .5-2.0 ppm, 2.0-4.0 ppm, or greater than 4.0 ppm. A peak exposure was defined as a short-term exposure (less than 15 minutes) that exceeded the TWA8 category.
After a follow-up of over 40 years, the researchers found a statistically significant association between peak formaldehyde exposure and death from all blood and lymphatic cancers combined. Workers with the highest peak exposures were 37% more likely to die from blood and lymphatic cancers than those with the lowest level of peak exposures. Furthermore, the risk of death from myeloid leukemia was 78% higher among workers with the highest peak exposure to formaldehyde compared with those with the lowest peak exposures.
The researchers concluded that there is a possible link between formaldehyde exposure and blood and lymphatic cancers. They believe that further study is warranted.
 Beane Freeman LE, Blair A, Lubin JH, et al. Mortality from lymphohematopoietic malignancies among workers in formaldehyde industries: The National Cancer Institute Cohort. Journal of the National Cancer Institute. 2009; 101: 751-761.