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Standard Operating Procedure:

 

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Corrosive Chemicals

Standard operating procedures (SOP) are intended to provide you with general guidance on how to safely work with a specific class of chemical or hazard. This SOP is generic in nature. It addresses the use and handling of substances by hazard class only. In some instances multiple SOPs may be applicable for a specific chemical (i.e., both the SOPs for flammable liquids and carcinogens would apply to benzene). If you have questions concerning the applicability of any item listed in this procedure contact the EHRS 215-898-4453 or the Principal Investigator of your laboratory. Specific written procedures are the responsibility of the Principal Investigator.

If compliance with all the requirements of this standard operating procedure is not possible, the Principal Investigator must develop a written procedure that will be used in its place. This alternate procedure must provide the same level of protection as the SOP it replaces. The Office of Environmental Health and Radiation Safety is available to provide guidance during the development of alternate procedures.

Corrosive chemicals are substances that cause visible destruction or permanent changes in human skin tissue at the site of contact, or are highly corrosive to steel. Corrosive chemicals can be liquids, solids, or gases and can affect the eyes, skin, and respiratory tract.  The major classes of corrosives include strong acids, bases, and dehydrating agents.  Liquid corrosive chemicals are those with a pH of 4.0 or lower or a pH of 9 or higher. Solid chemicals are considered corrosive when in solution; they fall in the above pH range. A highly corrosive chemical has a pH of 2 or lower or a pH of 12.5 or higher. Injurious chemicals cause tissue destruction at the site of contact. 

Some examples of corrosive materials:

Strong Acids:  hydrochloric, sulfuric, phosphoric

Strong Bases:  hydroxides of sodium, potassium, ammonia

Strong Dehydrating Corrosives:  sulfuric, phosphophrous pentoxide, calcium oxide

Strong Oxidizing Corrosives:  concentrated hydrogen peroxide, sodium hypochlorite

Corrosive Gases:  chlorine, ammonia

Corrosive Solids:  phosphorous, phenol

 

JUMP TO SECTION IN THIS S.O.P.

 

Before you begin

  • Approvals and Notifications
    • Most corrosives can be used by properly-trained individuals in the laboratory environment without the need for specific EHRS approval.  Special circumstances, such as abnormally large-scale use may require evaluation.  Contact EHRS at x84453 for assistance.
    • EHRS should be notified before purchasing hydrofluoric acid for use in your laboratory for the first time.  See the HF Safety Fact sheet for more details about working with liquid hydrofluoric acid. 
    • EHRS should be notified before purchasing certain corrosive compressed gases such as anhydrous ammonia.
    • Training required
      • Training requirements based on job duties and responsibilities are determined for each employee by completing the Penn Profiler.
      • Any corrosives users should have taken an Introduction to Laboratory Safety course as well as any required annual updates.
      • Most introductory programs are offered monthly. Dates are published in the Almanac and on the EHRS website. Annual updates of these programs can be completed online. For more information on these programs or to request a training program on safety or health topics for your department, please contact Valerie Perez at 215-746-6652 or send email to: traininghelp@ehrs.upenn.edu
      • Purchasing materials
        • Purchase of any container of corrosives with a volume of greater than 5 gallons for laboratory use requires EHRS approval.  
        • Hazard Assessment
          • A hazard assessment for work involving corrosives must thoroughly address the issues of proper use and handling, fire safety, chemical toxicity, storage, and spill response.
          • A hazard assessment must be conducted when a process/reaction/work-up/or purification is changed or when scaling-up any corrosives use to more than 10 times the original volume. 
          • The first time a highly hazardous corrosive material such as concentrated sulfuric or nitric acid is used for a process, a hazard assessment should be conducted.
          • Upon request EHRS can assist you in performing a thorough hazard assessment.

 

Setting-up

  • Storage:  Corrosive Chemical Storage Cabinets
    • Chemicals should be segregated according to the Chemical Storage and Transportation section of the Chemical Hygiene Plan
    • Cabinets:  Specially designed corrosion resistant cabinets should be used for the storage of large quantities of corrosive materials. For new lab construction, renovations, and whenever possible in existing labs, the specifications for acid cabinets found in the Laboratory Design & Equipment section of the EHRS website should be followed.  Cabinets for storing alkaline corrosive materials should be of the same construction whenever possible.
    • If no corrosion-resistant cabinet is available, store corrosives on plastic trays.
    • Do not store corrosive liquids above eye level.
    • Engineering Controls (ventilation, shielding, vacuum protection)
      • Safety Shielding:  Shielding is required any time there is a risk of explosion, splash hazard or a highly exothermic reaction.  All manipulations of corrosives which pose this risk should occur in a fume hood with the sash in the lowest feasible position.  Portable shields, which provide protection to all laboratory occupants, are also acceptable.
      • Special Ventilation:  Corrosive materials must be handled in a chemical fumehood if production of corrosive vapor is anticipated.  Manipulation of corrosives outside of a fume hood may require special ventilation controls in order to minimize exposure to the material. Fume hoods provide the best protection against exposure to corrosives in the laboratory and are the preferred ventilation control device. Always attempt to handle quantities of corrosives greater than 500 mL in a fume hood. If your research does not permit the handing of large quantities of corrosives in your fume hood, contact the EHRS to review the adequacy of all special ventilation. 
      • Vacuum Protection:  Evacuated glassware can implode and eject flying glass, and chemicals. Vacuum work involving corrosives must be conducted in a fume hood, glove box or isolated in an acceptable manner.  Mechanical vacuum pumps must be protected using cold traps and, where appropriate, filtered to prevent particulate release. The exhaust for the pumps must be vented into an exhaust hood. Vacuum pumps should be rated for use with corrosives. 
      • Personal Protective Equipment
        • Splash proof goggles in addition to standard laboratory personal protective equipment (PPE) consisting of a 100% cotton lab coat, closed toe shoes and nitrile gloves must be worn when there is a significant risk of splash.  Pouring very large volumes or handling particularly corrosive materials may require additional PPE consisting of thicker gloves and an apron. Contact EHRS with assistance in selecting chemical resistant personal protective equipment that is appropriate for the materials you are handling and the type of work you are doing.
        • Eye protection in the form of safety glasses must be worn at all times when handling corrosives. Ordinary (street) prescription glasses do not provide adequate protection. (Contrary to popular opinion these glasses cannot pass the rigorous test for industrial safety glasses.) Adequate safety glasses must meet the requirements of the Practice for Occupational and Educational Eye and Face Protection (ANSI Z.87. 1 1989) and must be equipped with side shields. Safety glasses with side shields do not provide adequate protection from splashes; therefore, when the potential for a splash hazard exists other eye protection and/or face protection must be worn.  In addition to safety glasses, a face shield should be worn when splash or spray is foreseeable. 
        • Gloves must be worn when handling corrosives.  Disposable nitrile gloves (4 mil minimum thickness) provide adequate protection against accidental hand contact with small quantities of most laboratory chemicals.  Lab workers should contact EHRS for advice on chemical resistant glove selection when direct or prolonged contact with hazardous chemicals is anticipated. 
        • Some examples of when specialty gloves may be necessary are:  Handling of hydrofluoric acid, when immersion in corrosive liquids is anticipated, when large volumes of corrosive liquids are being transferred or dispensed. 
        • At a minimum, 100% cotton lab coats, closed toed shoes and long-sleeved clothing must be worn when handling corrosives.  Additional protective clothing, such as a chemical-resistant apron, should be worn if the possibility of skin contact is likely.   
        • Protect all skin surfaces from contact with corrosive or irritating gases and vapors. 
        • Emergency Irrigation (Eyewash and safety shower)
          • A safety or drench shower should be available within 10 seconds of travel from where the corrosives are used. 
          • Safety showers are tested annually by facility’s personnel. 
          • Where the eyes or body of any person may be exposed to corrosives, suitable facilities for quick drenching or flushing of the eyes and body shall be provided within the work area for immediate emergency use.  Bottle type eyewash stations are not acceptable. 
          • Eyewashes must be activated weekly by laboratory workers to ensure proper function of equipment and to flush the plumbing. 

 

Carrying out your work

Consult the Material Safety Data Sheet (MSDS) for any new corrosive chemicals you introduce to your lab.  Fully assess the potential hazards and consider what safety equipment will be needed before you begin your work.  EHRS can provide you with an MSDS for any chemical you plan to use.

  • Handling
    • Handling process for liquids should be designed to minimize the potential for splash, splatter, or other likely scenarios for accidental contact.
    • Do not pour water into acid.  Slowly add acid to water with stirring and cooling if heat generation can be anticipated.
    • Reactions involving acids and bases are often very exothermic
      • Use only heat resistant labware
      • Allow for extra volume in your mixing or reaction vessel to account for expansion and/or foaming
      • It may be necessary to pre-cool solutions and cool while mixing or reacting
      • Corrosive Gases
        • Corrosive compressed gases can burn and destroy body tissue (especially the eyes or respiratory contact) on contact.  The magnitude of the effect is related to the solubility of the material in the body fluids.  Highly soluble gases such as ammonia or hydrogen chloride can cause severe nose and throat irritation, while substances of lower solubility such as nitrogen dioxide, phosgene, or sulfur dioxide can penetrate deep into the lungs.  Corrosive gases also can corrode metals.  Warming properties such as odor or eye, nose or respiratory tract irritation may be inadequate with some substances.  Do not rely upon these symptoms as warning of overexposure. 
        • All procedures detailed in the Compressed Gases Standard Operating Procedure should be followed for work with corrosive gases.
        • Perform manipulations of materials  that pose an inhalation hazard in a chemical fume hood to control exposure. 
        • To prevent environmental pollution and damage to equipment it may be necessary to trap and or scrub exhaust from processes which utilize corrosive gases even when working in the fume hood.  Contact EHRS for assistance with design and set-up of gas neutralization processes.
        • When corrosive gases are to be discharged into a liquid, a trap, check valve, or vacuum break device must be employed to prevent dangerous reverse flow.
        • Regulators and valves must be closed when the cylinder is not in use and flushed with dry air or nitrogen after use.
        • Labeling
          • All corrosives must be clearly labeled with the correct chemical name.  Handwritten labels are acceptable; chemical formulas and structural formulas are not acceptable. 
          • The label on any containers of corrosives should say “Flammable” and include any other hazard information, such as “Flammable” or “Toxic”, as applicable.
          • Heating/Open flame
            • Do not store corrosives in chemical fume hoods or allow containers of corrosives in proximity to heating mantles, hot plates, or torches.
            • Transferring/Dispensing
              • Weighing, transferring, and dispensing of corrosive solids must be performed carefully to avoid aspiration and ingestion of airborne powders and solids. 
              • The materials of construction for lab apparatus and vessels that will come in contact with corrosive chemicals must be evaluated for compatibility with the chemical in use.
              • Transport corrosives in secondary containment, preferably a polyethylene or other non-reactive bottle carrier and/or a sturdy cart designed for chemical transport.
              • When combining acid and water, always add ACID to WATER

 

Cleaning-up

  • Small spills
    • Anticipate spills by having the appropriate clean up equipment on hand. The appropriate clean up supplies can be determined by consulting the material safety data sheet. This should occur prior to the use of any corrosives.
    • Corrosive spill controls neutralize the hazardous nature of the spilled material. Acids and bases require different types of spill control materials.
    • Specific acid and base neutralizing spill kits are available from Fisher Scientific.
    • Sodium carbonate (soda ash) can also be used to neutralize spills of acidic liquids prior to clean-up.  Do not attempt to neutralize a hydrofluoric acid spill.  EHRS should be notified to handle all spills involving hydrofluoric acid.
    • In the event of a spill all personnel in the area should be alerted. Turn off all sources of ignition.
    • Waste disposal
      • Corrosives are hazardous wastes.  Questions regarding waste disposal should be directed to the EHRS. 
      • Vented caps for 1-gallon sized plastic containers are available from EHRS for collection of wastes that are likely to produce gas.  These wastes include mixtures of corrosive liquids and peroxides (such as Piranha and Chromerge).

 

Emergencies

  • Decontamination
    • Personnel: Immediately flush contaminated area with copious amounts of water after contact with corrosive materials. Remove any jewelry to facilitate removal of chemicals. If a delayed response is noted report immediately for medical attention. Be prepared to detail what chemicals were involved.
    • If the incident involves hydrofluoric acid (HF), seek immediate medical attention.
    • If there is any doubt about the severity of the injury, seek immediate medical attention.
    • Area: Decontamination procedures vary depending on the material being handled.  Contact EHRS in the event of a large spill.
    • Large spills
      • Do not attempt to handle a large spill of corrosives. Vacate the laboratory immediately and call for assistance.
        • Office of Environmental Health & Radiation Safety, 215-898-4453
        • University Police 511 or 215-573-3333. This is a 24 hour service.

 

  • Remain on the scene, but at a safe distance, to receive and direct safety personnel when they arrive.
  • Fire
    • Pull the fire alarm
    • Turn out the lights and close your laboratory door when everyone is out
    • Evacuate the building
    • Call 511 from a university phone or 215-573-3333 from a safe location to give Penn Police more information about the fire situation
    • Make yourself available to give emergency responders information as needed