Elegant work recently highlighted in Toxicological Sciences demonstrated that inhalation of formaldehyde results in the formation of DNA adducts in the nasal region of rats but not in distal tissues such as bone marrow (Lu et al., 2010). Lu et al. (2010) interpreted these findings as supporting the implausibility of formaldehyde induction of leukemia, a disease that has been controversially linked to occupational formaldehyde exposure (e.g., Bachand et al., 2010; Zhang et al., 2009, 2010). Despite debate about causal linkage, the International Agency for Research on Cancer recently concluded that there are sufficient data to support an association between formaldehyde exposure and myeloid leukemia (Baan et al., 2009). The results of Lu et al. (2010) argue against formaldehyde-induced DNA adduct formation beyond the nasal epithelium and underscore the need to further examine the epidemiological evidence for the association between formaldehyde exposure and leukemia as well as to consider alternative mechanisms.