Background and Overview of Hazards

Formaldehyde (HCHO) is an organic compound and the simplest aldehyde. It is a colorless gas with a pungent odor and is most commonly used as a saturated aqueous solution (formalin).

Formalin is usually supplied as 37% by weight of formaldehyde and 6-13% by volume of methanol in water. Methanol is added to stabilize the solution, suppressing oxidation and polymerization. This aqueous solution is combustible.

Formaldehyde has an acute toxicity by inhalation, ingestion, and dermal exposure. It is both corrosive to the skin and eyes, and is a suspected carcinogen. Upon exposure, formaldehyde can cause an immune system response due to the sensitizing nature of the chemical. Eye, nose, and throat irritation occurs upon exposure that can cause coughing and wheezing. Allergic reactions can occur upon exposure, and Ingestion of the chemical can be fatal. The National Institute for Occupational Safety and Health (NIOSH) considers 20 ppm of formaldehyde to be immediately dangerous to life and health (IDLH).

Depending on the use of the chemical, anyone using formaldehyde must comply with either the OSHA Laboratory Standard (29 CFR 1910.1450) or Formaldehyde Standard (29 CFR 1910.1048). Both standards require that the permissible and short time exposure limits are not exceeded. The permissible exposure limit (PEL) is 0.75 ppm measured as an 8-hour time weighted average (TWA).The short-term exposure limit (STEL) is 2 ppm which is the maximum exposure allowed in a 15 minute period.

Anyone working with or near formaldehyde/formalin should perform a risk assessment to determine their potential exposure. Initial air and exposure monitoring may be required in some cases. A standard operating procedure should be developed to describe laboratory specific information for handling the chemical.

Safe Handling

Proper engineering controls must be utilized when working with any form of formaldehyde. In laboratories, formaldehyde must be used in a functioning chemical fume hood. In areas where a chemical fume hood is not available, other forms of local exhaust ventilation (e.g. canopy hood, elephant trunk) should be used. If local exhaust ventilation is not feasible or insufficient to keep the concentration below the PEL, respirators must be worn by those exposed to the vapors. It is required that those using respirators complete a medical evaluation and are fit tested by the Division of Safety and Compliance (S&C).  S&C should be contacted to perform air monitoring in these areas to determine potential exposures.

  • At a minimum wear standard laboratory attire: closed-toe shoes, long pants, a lab coat, safety glasses with side shields or splash goggles and gloves.
  • Keep sources of ignition away when handling formalin solutions.
  • Keep containers tightly closed when not in use.
  • Store in a well-ventilated place.
  • Unstabilized solutions may require refrigeration. Refer to section 7 in the product's Safety Data Sheet (SDS) for manufacturer recommended storage conditions.


In work areas where the concentration of airborne formaldehyde exceeds either the TWA or the STEL, OSHA 1910.1048 requires signs on all entrances with the following legend:






Access to these work places has to be limited to authorized personnel that have received training on the hazards of formaldehyde and safe handling procedures.

Emergency Procedures

Ingestion: Do not induce vomiting. Rinse mouth with water. Seek medical attention.

Skin Contact: Immediately remove all contaminated clothing. Rinse affected skin with water and then wash with soap and water. Seek medical attention if necessary.

Inhalation: Remove victim to fresh air and keep at rest in a position comfortable for breathing.

Eye Contact: Rinse cautiously with water for several minutes. If contact lenses are present, remove if possible. Continue rinsing. Seek medical attention if necessary.

Fire: Use water spray, alcohol-resistant foam, dry chemical, or carbon dioxide fire extinguishers.

Spills: Before cleaning up a spill, make sure you are wearing appropriate PPE (gloves, lab coat, safety glasses). Spills of a formalin solution should be cleaned up immediately, using non-flammable absorbent pads. Have enough material readily available before working with the chemical.

If neutralization powder is available, it is best to neutralize the formalin before cleanup. Commercial neutralizing powders or solutions can be purchased from your preferred vendor (e.g., VWR, Grainger, Fischer Scientific, etc.). Follow the directions for the product.

If the spill is defined as a complicated spill, evacuate the area, alert others, and call 911 for emergency response.


Formalin solutions stabilized with methanol are usually stable at room temperature. Store them away from heat sources. Unstabilized solutions may require refrigeration. Refer to section 7 in the product’s SDS for manufacturer recommended storage conditions.

Waste Disposal

Collect all waste and dispose of by DRS. The following UI#s for formaldehyde containing waste are established to request a waste pick-up:

14176: Formaldehyde solution – used

16188: Formaldehyde solution (formaldehyde, methanol, water)

496: Formaldehyde, aqueous

11900: Formaldehyde/formalin with blood (non-infectious)

453: Formalin


Formaldehyde SDS

e-EROS Formaldehyde Article

OSHA guidelines for formaldehyde use

Last Updated: 9/19/2019