Furniture varnishes may contain acid-cured urea–formaldehyde resins dissolved in
organic solvents. In Finland, workers were exposed to an average level of about 1 ppm
[1.23 mg/m3] formaldehyde in most facilities (Priha et al., 1986; Heikkilä et al., 1991).
In a recent study in wood-working shops in Egypt, the levels of formaldehyde were
found to average 0.42 and 0.64 ppm [0.52 and 0.79 mg/m3] in ventilated and unventilated
workplaces, respectively (Abdel Hameed et al., 2000). [The origin of the formaldehyde
was not stated.]