Figure 1.

Relative risks of leukemia in the NCI industrial worker cohort compared to study subjects in the low-exposure category for (a) peak, (b) average, and (c) cumulative formaldehyde exposure. The “no exposure” category is comprised of workers from facilities that were presumably unexposed. The only statistically significant trends were for peak exposure when the “no exposure” workers were included in the analyses; all other trend tests including or excluding the “no exposure” workers were null. (See colour version of this figure online at www.informahealthcare.com/txc)