The BG institute for occupational safety (BIA) studied the capacity of polycyclic aromatic hydrocarbons to penetrate breathing tubes, and the potential hazard posed by this capacity to employees. The results show the material of which tubes are generally manufactured to be capable of resisting permeation by PAHs only for a limited time (approximately 30 days). Less volatile PAHs were detectable within the tubes after only 50 to 60 days. More highly volatile PAHs were not detected. A teflon-sheathed tube resisted permeation by PAHs for the entire test duration of 275 days. |