We found that worker’s exposure to xylene (4.7¡5.5 ppm) was lower than the standards
recommended by the American Conference of Governmental Industrial Hygienists (ACGIH) and the
Occupational safety and health administration (OSHA). Despite the low TWA exposures, the short-term
exposures for some workers were higher than STEL levels. Three canopy hoods were designed and
installed with capture velocities of 0.508 m second21 and duct velocity of 10.16 m second21.
Conclusion: We found that an exhaust ventilation system had a significantly reduced occupational
exposure to xylene vapor.