Environmental impact of hydraulic fracturing in the United States tuberculosis, kidney disease, autoimmune disorders and airway disease such as asthma and bronchitis. Most of these debilitating and potentially fatal diseases are preventable with occupational control measures regarding respirable crystalline exposure. Hydraulic fracturing uses abundant amounts of sand in the process of fracturing as part of the hydraulic fluid. The fracturing fluid consists of a base fluid, proppant and chemical additives. The majority of proppant used in fracturing are made of silica (sand). Truck loads of sand are delivered to the sites, then loaded to sand movers that are then transferred to a blender that mixes the hydraulic fluid. The
Hydrochloric acid (roughly 20.2%) can be used as a primary standard in quantitative analysis, although its exact concentration depends on the atmospheric pressure when it is prepared. Hydrochloric acid is frequently used in chemical analysis to prepare ("digest") samples for analysis. Concentrated hydrochloric acid dissolves many metals and forms oxidized metal chlorides and hydrogen gas. It also reacts with basic compounds such as calcium carbonate or copper(II) oxide, forming the dissolved chlorides that can be analyzed. Physical properties of hydrochloric acid, such as boiling and melting points, density, and pH, depend on the concentration or molarity of HCl in the aqueous solution.