Most exposures to benzene occur by inhalation. Its odor threshold generally provides adequate warning of acutely hazardous concentrations (odor threshold 1.5-5 ppm). Benzene vapor is heavier than air and may cause asphyxiation in enclosed, poorly ventilated, or low-lying areas.
Children exposed to the same levels of benzene vapor as adults may receive larger dose because they have greater lung surface area:body weight ratios and increased minute volumes:weight ratios. In addition, they may be exposed to higher levels than adults in the same location because of their short stature and the higher levels of benzene vapor found nearer to the ground