Formaldehyde
exposure to wood dust, and lack of details in the reports. At best a weak positive response is
indicated, at the site of initial contact.
Carcinogenicity
Studies in animals
Formaldehyde has been tested in chronic animal studies and a number of other experimental models
to assess its carcinogenic potential in different species. Inhalation of concentrations of 10 ppm (12
mg/m 3 ) or above leads to clear increases in nasal tumor incidence in rats. Marked non- neoplastic
pathological lesions of the nasal cavity were present at tumorigenic concentrations. In contrast, no
significant numbers of tumors were seen in mice and Syrian hamsters following chronic exposure to
concentrations up to 14.3 or 30 ppm (17 - 36 mg/m 3 ), respectively.
These clear species differences appear to be related, in part, to the local dosimetry and disposition of
formaldehyde in nasal tissues. For example, mice possess the capacity to minimize inhalation of
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