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ABP Use of Formaldehyde for Fixation of Whole Animals and Tissues

1. Purpose and Scope

This Animal Biosafety Procedure (ABP) describes the general practices and procedures to be used when working with formaldehyde (available as a 37% solution) or paraformaldehyde (white crystalline powder of polymerized formaldehyde) in whole animals or tissues, especially when performing perfusion fixation, which presents a higher risk of exposure to the user than does immersion. Formaldehyde is a carcinogen and its use must conform to the Occupational Safety and Health Administration (OSHA) National Research Council Recommendations Concerning Chemical Hygiene in Laboratories, 29 CFR 1910.1450 App A, OSHA Hazard Communication, 29 CFR 1910.1200 and OSHA General Industry Standard Formaldehyde 29 CFR 1910.1048.

Alternative practices, procedures, and equipment may be used, but they must be described in an attachment at the end of this document or in a separate user-generated Standard Operating Procedure (SOP), and approved by EHS and the IACUC before use.

2. Responsibilities

The Principal Investigator will ensure that personnel are made aware of the hazards associated with formaldehyde and that they receive training commensurate with their activities prior to commencing experiments. Personnel will comply with the safe work practices and procedures described within this Animal Biosafety Procedure.

3. Administrative Controls

  • 3.1 Training and Exposure Monitoring

    • 3.1.1 Complete CULearn Trainings: EHS Laboratory Safety (EHS 2555), Formaldehyde Awareness (EHS 2341), Chemical Waste Disposal (EHS 2716), Cleaning up Small Lab Spills (EHS 2394)
    • 3.1.2 Review the Safety Data Sheet (SDS), Formaldehyde Awareness Toolbox Safety Talk and obtain laboratory-specific training/orientation for the manipulation of formaldehyde, perfusion techniques, symptoms associated with accidental exposure, and spill and exposure response procedures.
    • 3.1.3 Airborne concentrations of formaldehyde must not exceed the Personal Exposure Limit (PEL) of 0.75 ppm over an 8-hour period; the Short Term Exposure Limit (STEL) must not exceed 2.0 ppm as a 15-minute exposure. Contact EHS Occupational Safety Health and Injury Prevention (OSHIP) for assistance with airborne measurements and any consequent modifications to control measures and signage.
    • 3.1.4 Formaldehyde is a carcinogen. Symptoms of acute exposure include irritation/burning of the eyes, skin and respiratory tract, tightening of chest, and headaches. Chronic exposure effects may result in asthma and chronic bronchitis, loss of smell, pulmonary edema, and nasopharyngeal cancer.
    • 3.1.5 CARE and EHS will provide additional on-site training, as necessary.
  • 3.2 Access and Signage

    • 3.2.1 Post a hazard sign at the designated area where and when formaldehyde will be used if there is a potential for airborne concentrations to exceed the exposure limits (see step 3.1.3)
  • 3.3 Medical Surveillance

    • 3.3.1 If handling live animals, participate in the Animal Users Health and Safety Program (AUHSP). 

4. Work Practice and Procedure Controls

  • 4.1 General Handling Practices

    • 4.1.1 Keep containers closed as much as possible.
    • 4.1.2 Use the smallest quantities for the experiment being performed. If weighing paraformaldehyde use a balance equipped with draftshield.
    • 4.1.3 Place as little volume of fixative solution into containers as possible, gently add specimens to limit splashing, and then gently pour fixative solution over the specimen, leaving some headspace at the top of the sample container.
    • 4.1.4 Use a tray to capture any spills, and work in well-ventilated areas, within a chemical fume hood where possible. If access to a chemical fume hood is not possible, contact EHS to assist with identification of an appropriate location to conduct this work.
    • 4.1.5 Wipe down work area with soap and water.
  • 4.2 Hygiene

    • 4.2.1 Eating, drinking, smoking, handling contact lenses, applying cosmetics, storing food for human consumption, and mouth pipetting are strictly prohibited in laboratory and animal facilities.
    • 4.2.2 Wash hands with soap and water after removing gloves.
    • 4.2.3 Do not wear PPE such as gloves and lab coats outside of work areas.
  • 4.3 Sharps Handling

    • 4.3.1 Substitute plasticware for glassware whenever possible, and implement the following practices described in the table:
      • Safe Practices for Handling Sharps
        Limit the use of sharps to when no other alternatives are available
        Keep all sharps in full view at all times
        Use only Luer-lock syringes and needles or units where the needle is integral to the syringe
        Implement safety engineered sharps where practical (retractable needles, needle tip shields, self-sheathing scalpels, etc)
        Dispose of sharps directly, without manipulation (i.e., do not bend, shear, break, recap, or use hands to remove needles from syringes or blades from scalpels), in an approved sharps disposal container. Maintain disposal container in animal room within arm’s reach
        Handle broken glass or other sharps with a secondary device such as forceps or broom and dustpan- not your hands
    • 4.3.2 Do not recap needles. However, if recapping must be done first receive approval by EHS and the IACUC, and use one of the following two methods: one handed scoop technique; forceps or tongs to place the cap on the needle.
  • 4.4 Spill Response

    • 4.4.1 For small spills (<100ml) don the appropriate PPE (see section 6) and use a formalin spill control sorbent, activated carbon, or absorbent pads. Cover the spill with the pad or pour the absorbent material around the outside of the spill and move inward to cover the entire spill. Scoop up the absorbed material and place material in plastic bag. There should be no free-flowing liquid.
    • 4.4.2 If you experience any irritation or other adverse reactions, or are not adequately prepared to clean up a small spill, refer to step 4.4.5.
    • 4.4.3 Label the bag with the EHS green Hazardous Waste label identifying all the contents. Make sure to leave the bag in the room (in a fume hood, when possible) where the spill occurred, and request removal via the EHS online waste pick-up request. Wash spill area several times with soap and water.
    • 4.4.4 For large spills evacuate the area and call 911 (from a campus phone) or 255-1111 (from a cell phone). Clearly identify location, chemical, concentration and amount, as well as any other details that are pertinent to the spill area.
  • 4.5 Handling of Waste

    • 4.5.1 Collect formaldehyde in compatible containers (e.g., glass, polyethylene). Label the container and request pick-up as described in step 4.4.3
    • 4.5.2 Dispose of formaldehyde contaminated sharps-related items (e.g., needles, syringes, Pasteur pipettes, and blood tubes) directly in a sharps disposal container.
    • 4.5.3 Collect carcasses/tissues in clear, labeled bags and store in a refrigerator until disposal.
    • 4.5.4 Refer to the appropriate Waste Disposal Guide (CVM or non-CVM) for more information 
  • 4.6 Transport, Storage, and Incompatibilities

    • 4.6.1 Transport formaldehyde and contaminated samples in a sealed, secondary container lined with absorbent toweling, and labeled with ”Formaldehyde” and/or formaldehyde right-to-know label.
    • 4.6.2 Store containers of formaldehyde in secondary containers in areas separate from the incompatible materials such as oxidizers, alkalis, inorganic acids, ammonia, phenol, isocyanates, peroxides, and anhydrides. These can be stored safely in a flammable storage cabinet or area under the fume hood.
    • 4.6.3 Keep away from heat, sparks, and flame.
    • 4.6.4 Formaldehyde reacts violently with nitrogen dioxide, perchloric acid/aniline mixtures and nitromethane. It also reacts with hydrochloric acid (HCl) and sodium hypochlorite (household bleach) to form the potent carcinogen, bis-chloromethyl ether.

5. Engineering Controls

  • 5.1 Handle powder and make dilutions in a certified chemical fume hood.

  • 5.2 Conduct procedures in an approved chemical fume hood, ducted biosafety cabinet, or use a local exhaust ventilation system, or downdraft table whenever possible to maintain airborne concentrations of formaldehyde at their lowest levels.

  • 5.3 Dilute solutions (e.g., 4% formaldehyde) may be handled on the bench top if there is sufficient room ventilation (i.e., air changes within room), but consult with EHS to determine if airborne concentrations will be below exposure limits (see section 3.1.3).

6. Personal Protective Equipment (PPE)

  • 6.1 Don the following minimum PPE before working with formaldehyde:

    • Safety glasses with side shields or chemical splash goggles
    • Protective outer garments (lab coat, coveralls), or disposable fluid resistant solid front gown
    • Nitrile disposable gloves- latex is not recommended. Use double nitrile gloves if there is extended contact, especially with higher concentrations (e.g., >4% formaldehyde).
    • Closed toed shoes
  • 6.2 Ensure there are no breaks in protective coverage (e.g., gloves overlap with sleeve of lab coat)

  • 6.3 Wear additional PPE (e.g., face shield, respiratory protection) when there is a risk of splash, appropriate engineering controls are not available (e.g., fume hood), or as indicated by the hazards or experimental conditions. (The use of respiratory protection will require enrollment in the EHS Respiratory Protection Program)

  • 6.4 Remove and replace PPE if contaminated or breached.

7. Response to Accidental Exposures

  • 7.1 Personnel who sustain an exposure such as a splash to eyes or other mucous membranes, direct contact with skin or respiratory inhalation should:

    • Wash exposed area in emergency eye wash or safety shower for at least 15 minutes and call 911 or (607) 255-1111.
    • Seek fresh air if respiratory exposure.
    • Notify supervisor and seek medical evaluation at Cornell Health, Occupational Medicine (607-255-6960 (off hours 607-255-5155)) as soon as possible. If after hours seek evaluation at Cayuga Medical Center.
    • Document exposures, injuries, and illnesses in the Cornell University Injury/Illness/Exposure Report, Incident Reporting

8. Emergency Phone Numbers

Updated July 15, 2020

More Information


  1. Cornell University Toolbox Safety Talk: Formaldehyde Awareness
  2. Cornell University Regulated Medical Waste
  3. National Research Council Recommendations Concerning Chemical Hygiene in Laboratories, 29 CFR 1910.1450 App A. Occupational Safety and Health Administration
  4. Hazard Communication, 29 CFR 1910.1200. Occupational Safety and Health Administration.
  5. National Research Council 1995. Prudent Practices in the Laboratory. National Academy Press: Washington D.C.
  6. 14th Report on Carcinogens
  7. NIOSH Carcinogen List. National Institute for Occupational Safety and Health
  8. List of Highly Hazardous Chemicals, Toxics and Reactives. Occupational Safety and Health Administration