High concentration acids, such as sulfuric, hydrochloric, and nitric acid, are significant chemical hazards in laboratory and industrial settings. These substances are intensely corrosive to nearly all organic tissue due to their ability to rapidly donate a proton. The primary risks are severe chemical burns from direct contact, thermal burns from highly exothermic reactions, and inhalation hazards from corrosive fumes or mists. Strict adherence to safety protocols is necessary to mitigate the danger these chemicals pose.
Essential Personal Protective Measures
Working with concentrated acids requires a multi-layered defense against splashes, fumes, and contact. Eye and face protection must consist of chemical splash goggles worn with a full-face shield. This dual protection guards against splattering events and ensures corrosive liquids cannot reach the eyes.
Hand protection must be selected based on the specific acid being used, as no single glove material protects against all chemicals. For strong, concentrated acids, gloves made from materials like butyl rubber or thick neoprene are preferred over standard nitrile. Consult a chemical resistance chart to ensure the glove’s breakthrough time exceeds the entire task duration.
The body must be covered by a non-flammable lab coat, such as treated cotton, and a chemical-resistant apron covering the torso and legs. This outer layer protects the skin and clothing from direct splashes and spills. Foot protection must consist of closed-toe shoes that cover the entire foot, preventing exposure from drops or small spills.
Safe Handling and Dilution Protocols
Procedural safety begins with using a certified fume hood for all transfers and manipulations of concentrated acids. The fume hood’s ventilation system captures and exhausts corrosive fumes, such as hydrogen chloride gas, preventing inhalation exposure. Secondary containment, like a non-reactive tray, should also be used during transport and work to catch spills and prevent the acid from spreading.
The most important rule when preparing solutions is to “Always Add Acid to Water, Slowly.” This rule addresses the highly exothermic reaction that occurs when strong acids are dissolved. The hydration of the acid ions releases a significant amount of heat energy.
If water is added to concentrated acid, the small volume of water immediately heats up, flashes into steam, and causes the acid to violently boil and splatter. When acid is slowly poured into a large volume of water, the water acts as a heat sink, safely absorbing the released thermal energy. The dilution process must use appropriate, non-reactive glassware, such as borosilicate glass, which can withstand the temperature changes and corrosive nature of the acid.
Preparing for and Responding to Chemical Exposure
Preparation for accidents involves knowing the location of the nearest safety shower and eyewash station before beginning work. These emergency fixtures must be easily accessible, typically within a 10-second walk, and the path to them must be unobstructed. This minimizes the delay in decontamination, which prevents permanent tissue damage.
In the event of skin or eye contact, immediately flush the affected area with copious amounts of water for a minimum of 15 minutes. For full-body exposure, activate the safety shower while removing all contaminated clothing; rapid decontamination is the priority. The continuous flow of water washes away the chemical and dilutes any residue.
For a spill on a work surface, use a spill kit with appropriate neutralizing agents, such as sodium bicarbonate. Water should not be used to clean up concentrated acid spills, as it can cause splattering or release heat and fumes. If corrosive fumes are inhaled, move the victim immediately to fresh air, and seek medical attention promptly.
Proper Storage and Waste Management
The safe management of high concentration acids includes proper storage and eventual disposal. Acids must be stored in designated cabinets, often made of wood or specialized plastic, because metal cabinets corrode rapidly from acid fumes. A primary control is the strict segregation of incompatible chemicals.
Acids must never be stored near bases, flammable materials, or strong oxidizers. This separation prevents a catastrophic reaction if a spill or container failure occurs. All containers must be clearly labeled and placed within secondary containment trays to catch leaks.
Disposal of spent or unwanted high concentration acids must follow strict institutional and regulatory guidelines for hazardous waste. Concentrated acid should never be poured directly down a sink or into the drain system. Before disposal, the acid must be neutralized or collected by a licensed hazardous waste contractor to ensure safe handling.