As a health hazard, corrosive substances cause destruction of, or alterations in, living tissue by chemical action at the site of contact. Major classes of corrosive substances include:

• Strong acids - e.g., sulfuric, nitric, hydrochloric, and hydrofluoric acids.
• Strong bases - e.g., sodium hydroxide, potassium hydroxide and ammonium hydroxide.
• Dehydrating agents - e.g., sulfuric acid, sodium hydroxide, phosphorus pentoxide and calcium oxide.
• Oxidizing agents - e.g., hydrogen peroxide, chlorine and bromine.

Symptoms of exposure for inhalation include a burning sensation, coughing, wheezing, laryngitis, shortness of breath, nausea, and vomiting. For eyes, symptoms include pain, blood shot eyes, tearing, and blurring of vision. For skin, symptoms may include reddening, pain, inflammation, bleeding, blistering and burns. As a physical hazard, corrosive substances may corrode materials they come in contact with and may be highly reactive with other substances. It is important to review information regarding the materials they may corrode, and their reactivity with other substances, as well as information on health effects. In most cases, these materials should be segregated from other chemicals and require secondary containment when in storage.

Wherever acids and bases are used, an eyewash and emergency shower must be available. If any corrosive chemical is splashed in the eyes, immediately go to an eyewash station and flush your eyes for at least 15 minutes. The importance of flushing for at least 15 minutes cannot be overstated. Once the eyewash has been activated, use your fingers to hold your eyelids open and roll your eyeballs in the stream of water so the entire eye can be flushed. After flushing for at least 15 minutes, seek medical attention immediately and complete an Incident Report. See all sections under Emergency and Exposures.

Handling Guidelines

The following guidelines should be adhered to when using peroxide forming chemicals:

• Concentrated acids and bases must be added to water to minimize the possibility that the heat of reaction will cause eruption of the corrosive.
  • Never add water to a concentrated acid or base as the water will layer on the top of the more densely concentrated acid or base. The extreme heat produced may boil and project the upper layer.
  • Always add a concentrated acid or base to water.
• Since the fumes of concentrated corrosives can cause severe external and internal burns, these solutions should be handled in a fume hood with the employees wearing rubber gloves, rubber apron and safety glasses. 
• If a spill occurs, neutralize spills of concentrated acid with dry sodium carbonate or bicarbonate, and neutralize spills of concentrated alkali with citric or boric acid.  Keep a supply on hand.
• Drips of acids or alkalis on the sides of containers are best cleaned off with paper towels. 
• Plastic stoppers are better than glass stoppers for glass bottles holding an alkaline solution. Alkalis tend to bind glass to glass making it sometimes impossible to remove a glass stopper. 
• For safe transportation of corrosives, protective packaging should be used. 
• When a corrosive chemical is to be disposed of, it should first be neutralized before adding to waste containers.
• Before transporting a carboy of acid or base, check to make certain the neck of the bottle is not broken.
• Ensure all glassware used to hold corrosive chemicals is well rinsed with water before sending to washup
• Picric Acid
  • Picric acid is explosive when dry and must be stored under water and kept out of contact with metals as much as possible.  Bottle necks and lids should always be wiped with a moist paper towel to prevent the formation of crystals around them.  Picric acid should never be allowed to reach a crystalline state, however, if this should happen - DO NOT HANDLE ANY PICRIC ACID IN THIS STATE - Contact RMS and PI immediately.
  • Metal contamination or storage in metallic containers should be avoided.

Storage Guidelines

• Store corrosive chemicals (e.g., acids, bases) below shoulder level and in secondary containers that are large enough to contain at least 10% of the total volume of liquid stored or the volume of the largest container, whichever is greater.
• Corrosive chemicals are best stored in special ventilated cabinets.
• Never store strong acids with bases or either of the two with flammable liquids or oxidizing chemicals. 
• Acids must always be segregated from bases and from active metals (e.g., sodium, potassium, magnesium) at all times and must also be segregated from chemicals which could generate toxic gases upon contact (e.g., sodium cyanide, iron sulfide).
  • Keep sealed when not in use. 
  • Specific types of acids require additional segregation.
  • Organic acids should be segregated from inorganic acids (mineral acids).
  • Oxidizing acids must be segregated from organic compounds including organic acids, flammable and combustible substances.
  • Inorganic acids and organic acids should be stored separately or in separate secondary containers.
  • Perchloric acid and hydrofluoric acid should be stored by themselves, away from all other chemicals.
  • Picric Acid is reactive with metals or metal salts and explosive when dry and must contain at least 10% water to inhibit explosion (see below for more information on picric acid).
  • Perchloric acid that is heated must be used in a specific fume hood to prevent formation of explosive powder residue, if your lab plans to use perchloric acid inform RMS immediately.

Hydrofluoric acid

Hydrofluoric acid (HF) is a corrosive material that is dangerous even at low concentrations (50 - 250 ppm) and brief exposure times. Skin contact causes serious skin burns, which may not be immediately apparent or painful since HF interferes with nerve function, initially blocking pain. Symptoms may be delayed 8 hours or longer, resulting in deep acid penetration and severe burns. The fluoride ion readily penetrates the skin causing destruction of deep tissue layers and bone. Systemic fluoride poisoning has been associated with sudden death due to cardiac arrest, which can occur with burns to as little as 2.5% of body surface area. Inhalation of HF vapor may cause ulcers of the upper respiratory tract and can lead to systemic fluoride ion poisoning.

HF should be used in an operational chemical fume hood. In addition to a chemical fume hood, the following personal protective equipment   is required for HF use:

• Rubber or plastic apron
• Gloves
  • Incidental use - double glove with heavy nitrile exam gloves and re-glove if any exposure to the gloves
  • Extended use - heavy neoprene or butyl over nitrile or silver shield gloves
• Splash goggles in conjunction with a fume hood sash
• Closed toed shoes
• Long pants and a long sleeve shirt with a reasonably high neck (no low cut)

HF is usually stored in polypropylene containers since it attacks glass and other silicon containing compounds. HF reacts with silica to produce silicon tetrafluoride, a poisonous, corrosive gas known to cause pneumonitis and pulmonary edema. Older polypropylene containers can become brittle or start to bubble. If such a container is found, contact RMS immediately. If concentrated HF contacts the skin call 911 immediately and inform medical personnel that a hydrofluoric acid exposure has occurred; and complete an Incident Report.

Labs using hydrofluoric acid must have a supply of either calcium gluconate gel (preferred), or a 10% W/V calcium gluconate solution on hand as an antidote. Topical applications of the gel or solution should be applied frequently and liberally while the victim is awaiting further medical attention. Contact RMS for more information.

Perchloric acid

Perchloric acid is a corrosive oxidizer that can be dangerously reactive. At elevated temperatures, it is a strong oxidizing agent and a strong dehydrating reagent. Perchloric acid reacts violently with organic materials. When combined with combustible material, heated perchloric acid may cause a fire or explosion. Cold perchloric acid at less than 70% concentration is not a very strong oxidizer, but its oxidizing strength increases significantly at concentrations higher than 70%. Anhydrous perchloric acid (>85%) is very unstable and can decompose spontaneously and violently. When using perchloric acid, remember the following:

• Be thoroughly familiar with the special hazards associated with perchloric acid before using it.
• If possible, purchase 60% perchloric acid instead of a more concentrated grade.
• Always wear rubber, neoprene, or nitrile gloves and chemical splash goggles while using perchloric acid. Consider also wearing a face shield and rubber apron if splashing is likely.
• Store perchloric acid inside secondary containment (such as a Pyrex dish) and segregated from all other chemicals and organic materials. Do not store bottles of perchloric acid in wooden cabinets or on spill paper.

For any work involving heated Perchloric acid (such as in perchloric acid digestions), the work must be conducted in a special perchloric acid fume hood. Perchloric acid hoods are generally made of non-corrosive materials (stainless steel), and are equipped with a water wash down mechanism in the ductwork. Perchloric acid fume hoods must be clearly labeled and used only for perchloric acid or other mineral acids, such as nitric, hydrochloric, and hydrofluoric. No organic solvents should be stored or used in these hoods. When perchloric acid is heated above ambient temperature, vapor is formed which can condense in the ductwork and form explosive perchlorates. After each use, the fume hood operator shall wash down the hood and ductwork with water.