Hydraulic fracturing in the United States with hydraulic fracturing activity versus those without, with each well addition increasing rates of accidents by 2% and risk of fatality by .6%. Rig-Up and Rig-Down are terms used to refer to the delivery, construction, dismantling and breakdown of equipment required throughout the hydraulic fracturing process. Incidents and fatalities during rig-up/rig-down operations may result if struck or crushed by the heavy equipment involved. Hazards during Mixing and Injection Workers may be exposed to dangerous chemicals while mixing and injecting fluids used in hydraulic fracturing. Potential chemicals include, hydrochloric and hydrofluoric acid, biocides, methanol, ethylene glycol, guar gum, polysaccharides and polyacrylamides,
Sol–gel process requires an excess of water and/or the use of a hydrolysis catalyst such as acetic acid or hydrochloric acid. Intermediate species including [(OR)−Si−(OH)] or [(OR)−Si−(OH)] may result as products of partial hydrolysis reactions. Early intermediates result from two partially hydrolyzed monomers linked with a siloxane [Si−O−Si] bond: or Thus, polymerization is associated with the formation of a 1-, 2-, or 3-dimensional network of siloxane [Si−O−Si] bonds accompanied by the production of H−O−H and R−O−H species. By definition, condensation liberates a small molecule, such as water or alcohol. This type of reaction can continue to build larger and larger silicon-containing molecules