The intent of OSHA’s Silica PEL is to keep people working in a safe environment. From the OSHA FAQ document above: “The National Institute for Occupational Safety and Health (NIOSH) first recom- mended this exposure limit to OSHA over 40 years ago, and the American Public Health Association has also recom- mended that OSHA adopt this PEL. The American Conference of Governmental Industrial Hygienists recommends an even lower exposure limit of 25 µg/m of air, averaged over an eight-hour day. OSHA established a PEL of 50 µg/m because the agency deter- mined that occupational exposure to respirable crystalline silica at the previous PELs resulted in a sig- nificant risk of developing or dying from silicosis and dying from lung cancer, other lung diseases, or kid- ney disease, and that compliance with a 50 µg/m PEL would substan- tially reduce that risk. OSHA also finds significant risk remaining at the new PEL, but considers a PEL of 50 µg/m to be the lowest level that can reasonably be achieved through use of engineering con- trols and work practices in most affected operations.” It’s critical to measure air qual- ity to determine the amount of dust in a worker’s breathing area in the specific area of exposure, such as during floor grinding or using a tile saw. The most accu- rate measurements take place in a full eight hours. The OSHA FAQ document states that “Published OSHA, NIOSH, and MSHA meth- ods for analyzing respirable crys- talline silica are able to measure concentrations at the new PEL and action level with acceptable preci- sion, based on analyses of qual- ity control samples and on studies conducted when those methods were developed in the 1970s.” The TECH TALK –––––––––––––––––––––––––––––––––––––––––––––––––––––––––– 66 TileLetter | June 2018