Sources Used in Preparation of this Document
Canadian Center for Occupational Health and Safety website:
OSHA fact sheet about quartz silica:
World Health Organization fact sheet:
National Toxicology Program, Department of Human Health and Services- Report on Carcinogens, 11th Edition: http://ntp.niehs.nih.gov/ntp/roc/eleventh/profiles/s161sili.pdf OSHA Silica Advisor: http://www.osha.gov/SLTC/etools/silica/silicosis/silicosis.html
Page 5 of 6iAmerican Journal of Respiratory and Critical Care Medicine: We found an increased risk of total mortality associated with each 10-μg/m
increase in average PM2.5 over
the entire follow-up period. Conclusion: Total, cardiovascular, and lung cancer mortality were each positively associated with ambient PM2.5 concentrations. Reduced PM2.5 concentrations were associated with reduced
mortality risk. http://ajrccm.atsjournals.org/cgi/content/full/173/6/667 American Thoracic Society, 2006 International Conference: Abstract B16. Presented May 22, 2006
The study showed that each increase of 10 μg/m2 of PM10 over 2 years increased the risk of death by 32% for patients with diabetes, by 28% for patients with COPD, by 27% for patients with congestive heart failure, and by 22% for people with inflammatory diseases such as rheumatoid arthritis or lupus. http://www.medscape.com/viewarticle/533039
ii Environmental Health Perspectives, Supplements Volume 108, Number S4, August 2000, “Agricultural Lung Diseases.”
Very high concentrations of inorganic dusts are generated by field activities such as plowing, tilling, haying, and harvesting. The bulk of the inorganic dusts are silicates. These include crystalline silica (quartz) and noncrystalline amorphous silica (diatomite). Newer tractors with enclosed cabs containing air filtration can decrease
33 respirable dust exposure from an average of 2-20 mg/m to 0.1-1 mg/m .
Inorganic dusts, however, do not contribute to agricultural respiratory disease to the same extent as organic dusts. Furthermore, the weathering effects upon respirable quartz dusts generated by agriculture are considered to be less pathogenic than the freshly fractured quartz dust generated by industrial processes such as mining, quarrying, and sandblasting. Diatomaceous silicate inorganic dusts are also considered to have relatively nontoxic pulmonary properties (7).
7. American Thoracic Society. Respiratory health hazards in agriculture. Am J Respir Crit Care Med 158:S1- S76 (1998) http://www.ehponline.org/members/2000/suppl-4/705-712kirkhorn/kirkhorn-full.html
iiiThe Air Quality Permit issued to Canadian Sand and Proppants, Inc. ( transferred to EOG Resources in May 2010 ) is based on a wrong theory of science. It claims that a safe level of PM10 guarantees a safe level of Silica Dust. This is not necessarily true. One has to know the percent of PM10 that is silica dust in order to make this claim. The amount of respirable silica dust could change, depending on the area of the quarry being mined, how much blasting is done, and other factors.