Laserfiche WebLink
Mr. Kevin T. Haroff AOL <br /> Page 5 <br /> performed using x-ray diffraction (using a modified NIOSH method <br /> 7500) to determine the fraction of free crystalline silica. The <br /> report stated that the only free crystalline silica type detected <br /> was cristobalite (no quartz or tridymite were detected) . In the <br /> bag house sample, 17.9 percent (by weight) of the total sample was <br /> found to be free crystalline silica; in the surge bin sample, 44.4 <br /> percent. In the bag house sample, 0.61 percent (by weight) of the <br /> total sample was found to be less than five An in size; in the <br /> surge bin sample, 0.106 percent. In the bag house sample, 5.3 <br /> percent (by weight) of the particles less than five µm in size were <br /> found to be free crystalline silica; in the surge bin sample, 40.3 <br /> percent. RJ Lee then calculated that the percent (by weight) of <br /> the total samples that was free crystalline silica with a particle <br /> size of less than five µm was 0.032 percent for the bag house <br /> sample, and 0.043 percent for the surge bin sample. Since 35 <br /> percent of the ash at the facility is collected in the surge bin, <br /> and the remaining 65 percent is collected in the bag house, the <br /> weighted average of the total samples that was free crystalline <br /> silica with a particle size of less than five µm was 0.036 percent. <br /> Since results from only one sample were provided, an 80 percent <br /> confidence interval could not be calculated. <br /> The Material Safety Data Sheet (MSDS) for this waste prepared <br /> September 15, 1989 by "Wadham Energy Ltd. , Partnership," indicates <br /> that 70 percent of the ash is amorphous silica. The balance of the <br /> ash is principally free crystalline silica, but also includes a <br /> small fraction (up to one percent) of carbon. <br /> DISCUSSION <br /> Wadham first claimed that even though the ash contains free <br /> crystalline silica, none of the free crystalline silica particles <br /> are of respirable size. Later, Wadham modified their position to <br /> claim that even though some of the ash particles are of respirable <br /> size, there is not a sufficient quantity of respirable free <br /> crystalline silica within the ash to cause any silica induced <br /> respiratory disease (i.e. , any airborne concentration from their <br /> facility would be "safe") . A concentration of a substance within a <br /> waste does not directly relate to "safe" levels of airborne <br /> particles, nor are specific exposure scenarios envisioned when the <br /> Department establishes thresholds for hazardous waste. <br /> There are numerous articles in the sc*entific literature <br /> establishing that inhalation of "respirable " free crystalline <br /> 3 The term respirable refers to particles which are <br /> sufficiently small to be aspirated into the human respiratory <br /> (Footnote Continued) <br />