Workers in hairdressing salons are exposed to several hundred chemicals, of which a few are possibly detrimental to pregnant workers or their fetuses. In Quebec, a government program provides protective reassignment for exposed pregnant workers. This study was set up to assist public health physicians by describing the exposure levels for ingredients that were measurable (i.e., airborne), selected from a list of possibly detrimental hairdressing ingredients. Twenty-six salons were sampled in Montreal, Canada, between June 1996 and December 1997. At the time of sampling, information on certain work conditions (e.g., chemical services offered, number of clients, average CO(2) level during the day) was also noted. Fifty percent of the salons provided additional services other than hairdressing, such as manicures, pedicures, or beauty treatments. Almost half of the salons were quite small, with less than 5 employees. Average temperature ranged between 17 and 26 degrees C, relative humidity between 18 and 59 percent and average CO(2) concentrations from 583 to 4301 mg/m(3). Duration of samples varied between 15 minutes and 8 hours. The most prevalent chemicals were alcohols: ethanol, at an average personal concentration of 39.9 mg/m(3), and isopropanol at an average personal concentration of 3.1 mg/m(3). Acetone, toluene, and acetates, all related to manicure services, were also measured in small quantities. An empirical mathematical model brought in evidence that CO(2) levels explained 46 percent of variation in the concentration of ethanol; when number of permanent waves done during the day and relative humidity and temperature were added, the resulting model explained 68 percent of the variations in ethanol. Thus, although the measured concentrations of chemicals were fairly low in this study, it appears possible that on very busy days, especially if other chemical services are performed in the salon, the total mixture of airborne chemicals could reach significant concentrations.