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,
Hydrochloric acid acid is in the pickling of steel, to remove rust or iron oxide scale from iron or steel before subsequent processing, such as extrusion, rolling, galvanizing, and other techniques. Technical quality HCl at typically 18% concentration is the most commonly used pickling agent for the pickling of carbon steel grades. The spent acid has long been reused as iron(II) chloride (also known as ferrous chloride) solutions, but high heavy-metal levels in the pickling liquor have decreased this practice. The steel pickling industry has developed hydrochloric acid regeneration processes, such as the spray roaster or the fluidized bed HCl regeneration process,