Workplace atmospheric asbestos levels in different plants manufacturing asbestos-cement roofing sheets in India

Environmental monitoring was conducted to determine the workplace atmospheric asbestos levels in three different plants of an asbestos-cement (AC) roofing sheet manufacturing industry located in North India. Air samples were collected for analysis of asbestos fibers at key locations in all the three plants including fiber warehouse and factory main gate in order to assess the industrial hygiene conditions prevailed in work zone of this factory. A total of 24 samples were collected and analyzed by phase-contrast and polarized-light microscopy. Observations on asbestos fibers collected on membrane filters suggest that they are chrysotile asbestos and their average concentrations ranged between 0.036–0.148 fiber per cubic centimeter (f/cc) (mean 0.075 ± 0.034 f/cc). These fiber counts are less than the existing Indian Standard (0.5 f/cc). However, fiber counts in the ingredient mixing locations of all the plants of AC factory are higher than the proposed Indian Standard (0.1 f/cc). Further improvement in the pollution mitigation technology is highly desirable in view of the carcinogenic nature of asbestos that persists for very long time in the biological systems as well as in the environment.