Standard Operating Procedure for Formaldehyde Solution Use in Small Animal Perfusion


Standard Operating Procedure for Formaldehyde Solution Use in Small Animal Perfusion

EHS SOP #: 004

Version No.: 2.0

Supercedes: N/A

Formaldehyde Solution Formula


Formaldehyde is a colorless, highly toxic, and flammable gas at room temperature. It is a strong smelling chemical which is commonly used in research and medical laboratories as an aqueous solution. This document establishes procedures for the safe handling and use of formaldehyde, formalin, and paraformaldehyde solutions used in perfusions. Formalin is a 40% formaldehyde solution while paraformaldehyde is a polymerized form of formaldehyde that depolymerises when heated. A 4% formaldehyde solution is typically used in animal perfusion. Note that 10% neutral buffered formalin is approximately 4% formaldehyde.

Health Effects

Formaldehyde can act as a sensitizing agent and is a known human carcinogen that is linked to nasal cancer and lung cancer. Acute exposure is highly irritating to the respiratory system and can cause headaches and eye and throat irritation at very low concentrations.

Signs of acute exposure

Nasal, throat, and pulmonary irritation.

Signs of chronic exposure

Headaches, rhinitis, drowsiness, respiratory impairment, kidney injury, pulmonary sensitization, and tissue damage. May also cause neuropsychological effects such as sleep disorders, irritability, altered sense of balance, memory deficits, loss of concentration, and mood alterations.

Regulatory Limits

The OSHA Formaldehyde standard (29 CFR 1910.1048) protects workers exposed to formaldehyde and applies to all occupational exposures to formaldehyde gas, its solutions, and materials that release formaldehyde.

The permissible exposure limit (PEL) for formaldehyde is 0.75 parts per million (ppm) of air as an 8 hour time weighted average (TWA). The short term exposure limit (STEL) is 2 ppm maximum exposure over a 15 minute period. OSHA also defines an action level of 0.5 ppm when calculated as an 8-hour TWA which requires increased monitoring and initiation of worker medical surveillance.

Air Monitoring

  • Area monitoring can be requested to assess potential exposures in the general laboratory work area. The monitoring is performed using a direct read instrument to give concentrations in room during perfusions.
  • Personal monitoring can be requested to determine potential exposures for individual employees who work with formaldehyde. The monitoring is performed using a passive dosimeter that the employee wears in their breathing zone to quantify potential exposure.
  • Air monitoring can be requested by contacting Environment, Health & Safety (EHS) at 919-962-5507.


Administrative Controls

Based on the risk associated with the use of formaldehyde solutions, the safety procedures outlined below are required by all research staff when working with formaldehyde.

  • Institutional Animal Care and Use Committee (IACUC) protocols that include formaldehyde should reference this SOP to verify that the standard operating procedures are being followed.
  • Anyone who uses formaldehyde solutions in perfusions is required to review this SOP and the attached Safety Data Sheet (SDS) prior to work.
  • Storage should take place in a cool, ventilated area, with a tightly closed container.
  • An eye wash should be available in the room with a safety shower accessible nearby.
  • Employees who use, or may be exposed to, formaldehyde solutions are required to have formaldehyde training.

Engineering Controls

  • Formaldehyde solutions used in perfusions should be used in a chemical fume hood, ducted biological safety cabinet, or downdraft table to achieve formaldehyde levels less than the TWA or STEL.

Personal Protective Equipment (PPE)

  • Nitrile gloves, a lab coat, and safety glasses.
  • When in rodent barrier facilities, PPE use must be consistent with the facility policy.

Waste Disposal

  • Unused solutions of formaldehyde will be disposed of as a hazardous material through EHS.
  • Formaldehyde waste should be stored in a closed container near the point of generation. Liquid waste containers should be kept in secondary containment.
  • Transfer of waste into a waste container should take place in a ventilated hood or biosafety cabinet. 
  • Do not discard perfusion waste down the sink.

Accidents or Injuries

Spill Procedures

  • Do not attempt to clean-up if you feel unsure of your ability to do so or if you perceive the risk to be greater than normal laboratory operations.
  • If a small spill occurs rapidly absorb any liquid with absorbent pads or paper towels and place in chemical fume hood for safe evaporation.
  • If a large spill occurs notify others in the area and evacuate room immediately. Contact EHS (919-962-5507) during working hours and 911 if after hours.

Contact Information

Policy Contact

Environment, Health & Safety
1120 Estes Drive
Campus Box #1650
Chapel Hill, NC 27599-1650
Phone: 919-962-5507

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Article ID: 132071
Thu 4/8/21 9:23 PM
Thu 5/5/22 4:11 PM
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02/23/2022 12:00 AM
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02/23/2022 12:00 AM
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Environment, Health and Safety