Healthy Indoors Magazine
Issue link: https://hi.healthyindoors.com/i/866924
Healthy Indoors 15 to ensure the work area is actually free of asbestos fibers (we already do this in schools under AHERA for large asbestos projects, and some schools re- quire all asbestos projects have to be cleared by AHERA TEM). In addition, any negative exposure assessment for floor tile removal that does not in- clude AHERA TEM analysis of some of the sam- ples should not be accepted as definitive to allow workers to not use respirators during asbestos floor- ing removal. As pointed out in the aforementioned study, there could be significant exposure to work- ers from respirable fibers/structures that the NIOSH 7400 method is not picking up. We look forward to a continuation of this debate, while we press the case for a requirement for AHERA TEM clearance for flooring removal projects. Angelo Garcia, III is founder and president of Future Environment Designs (FEDTC), one of the nation's leading indoor air quality, industrial hygiene and safe- ty training companies that is based in Syosset, New York. He has been a consultant and trainer working with government and industry on issues relating to asbestos and indoor air quality since he founded the company in 1988. An industrial hygien- ist since 1981, Mr. Garcia is a Council-Certified Indoor Environmental Consultant (CIEC), Certified Emergency Operations Professional (CEOP), and has achieved the highest level of accreditation in the field. His background includes extensive training from various agencies includ- ing the Occupational Safety and Health Administration (OSHA); the Department of Housing and Urban Devel- opment (HUD); the New York State Department of Labor (NYS DOL); United States Environmental Protection Agen- cy (USEPA) and the New York City Department of Environ- mental Protection (NYC DEP). www.futureenvironmentdesigns.com ag3@futureenvironmentdesigns.com 5 microns with a 3:1 or greater length-to-width ratio are counted. • Many research studies have found the pre- ponderance of fibers at autopsy left in lung tissue, pleural plaques, and lymph nodes of persons who have occupational exposure to asbestos are shorter them 5 microns in length. • The NIOSH 7402 TEM method is flawed be- cause it underreports the amount of asbestos in the samples. It ignores all fibers less than or equal to 5 microns, and all those fibers lon- ger than 5 microns but less than 0.25 micron in diameter. • AHERA TEM method counts for total asbes- tos structures per cubic centimeter averaged 22 times greater than the PCM fiber counts on the same filters. • AHERA TEM asbestos concentrations ob- tained during mastic abatement with a com- mercial mastic remover averaged 11 times higher than those measured when removal used amended water. • The study also found that there were consid- erable amounts of asbestos dust settled on exposed surfaces during tile removal. This indicates a need to thoroughly HEPA vacuum and wet clean surfaces, or contaminated dust may remain that could be re-entrained by oc- cupant activity. • The study also indicates that workers in these areas, would not have to wear respi- rators, so anyone in these areas would have inhaled asbestos fibers or structures of re- spirable dimensions. • The study suggests that for Resilient Floor- ing Removal clearance sampling should use aggressive methods, and require a clear- ance level of less than 0.005 structures per cubic centimeter for each sample, with all samples analyzed by AHERA TEM protocol. It also suggests a minimum number of sam- ples for clearance should be one sample per 500 square feet, a volume of air of at least 1250 liters, and the use of 0.45 micron mixed cellulose ester filters in a 25-millimeter diam- eter conducting cassette with a 50-millimeter extension cowl. After reading this study, it becomes apparent that asbestos containing flooring or mastic removal should be cleared using the AHERA TEM method