Is formalin flammable?

In this blog post, we will answer the question, “Is formalin flammable?”. We will also discuss what formalin is, the flash point, reactivity, and guidance of storing formalin, and then how to extinguish fire caused by formalin.

Is formalin flammable?

Yes. Formalin is flammable. It is a 37% formaldehyde solution with a flash point of 185°F. This low flashpoint makes formalin categorized as a flammable liquid according to OSHA.

What is formalin?

Formalin is a formaldehyde solution that has a concentration of about 37%. Organic chemical formaldehyde has a CH2O structure originating from the incomplete combustion of various organic molecules. 

It may be found in the smoke from smoky meats such as pork and fish. Formaldehyde is often found in the air, especially in major cities. It is commercially manufactured utilizing the catalytic vapor phase oxidation of methanol using air as the oxidant and silver, copper, alumina, or coal as the catalyst.

This solution is colorless or virtually colorless like water, mildly acidic, has a powerful and caustic odor, decomposes when heated, and produces formic acid. 

Formaldehyde reacts aggressively with oxidizing agents and a wide range of organic molecules. It reacts with hydrochloric acid to form bischloromethyl ether (BCME), which is very poisonous. 

At 25°C, the pKa of formalin is 13.27; the boiling point is 101°C; the density is 1.067 (air=1); the flash point is 85°C; and it is soluble in alcohol, ether, acetone, benzene, and benzene. Solubility in water: 4 x 105 mg/L at 20°C.

Formalin is widely recognized as a pest killer (disinfectant) and specimen preservation (fixative) and is commonly utilized in sectors including the plywood industry as an adhesive. 

So far, its usage is not forbidden, but every person involved in carrying and processing this material must be careful because the hazards connected with this substance are reasonably substantial. As a disinfectant, formalin 2–8 percent is commonly employed.

Formalin is frequently misapplied as a food preservative, even though it is illegal (given the compound’s dangers). Those in the food industry who are careless engage in such unethical behavior. 

Examples of foods that may contain formaldehyde include salted fish, fresh fish, wet noodles, and tofu. Formaldehyde is not present in all food items, though.

What are the uses of formalin?

The uses of formalin include:

  • When used for cleaning, it effectively eliminates germs from surfaces such as floors, ships, warehouses, and clothing.
  • Fly and other insects killer
  • Mirror dyes, glass, and explosives are used to produce synthetic silk.
  • It is commonly used to harden gelatin and paper coatings in two photography.
  • In the form of urea-formaldehyde, it is utilized to produce continuous-release fertilizer.
  • Essential oils and perfume ingredient.
  • Nail hardeners and cosmetic preservatives
  • Oil well corrosion protection
  • Foam insulation components: materials available
  • Plywood-specific adhesives
  • Preservatives such as home cleaners, dishwashing liquids, softening agents, shoe care products, automobile shampoos, and carpet cleaners utilize formalin as a preservative in small quantities (less than 1%).

What is the flashpoint of Formalin?

The flash point of formalin is 185oF. When heated to 185 degrees Fahrenheit, formalin emits steam or gas, which can ignite and burn for a brief period when exposed to a heat source or pilot flame. 

This temperature is low enough that formalin is included in the category of flammable liquid, according to OSHA.

What is formalin’s reactivity?

Formaldehyde solution is stable under normal conditions. A white precipitate may arise from self-polymerization. 

It is not safe to mix formalin with acids and bases, oxidizing agents, reducing agents, metals and their salts, halogens, flammable compounds, and peroxides. 

Formalin should not be mixed with any of these. An explosion occurs when formalin, peroxide, nitrogen dioxide, and performic acid combine. Steel may be corroded by formalin.

What are the safest methods for storing formalin?

The safest methods for storing formalin are:

  • Separate from incompatible substances, such as oxidizing and alkaline chemicals, in a closed closet out of the reach of youngsters.
  • Minimize the chances of physical damage.
  • Keep dry by installing ground-level ventilation. 
  • To inhibit polymerization, 10% to 15% methanol is added to the formalin solution.

What are the circumstances that must be avoided when working with formalin?

When you’re working with formalin, avoid:

  • Sparks, fires, and other ignition sources. Containers can be damaged or burst if they are exposed to high temperatures.
  • Contact with incompatible substances, such as acids, bases, oxidizing and reducing agents, metals, metal salts, halogens, flammable materials, and peroxides.
  • Do not get too close to water supply pipes or drains.

What should you do if you spill formalin?

  • A little spill should be cleaned up with sand or another non-combustible substance. Spills should be contained until adequately disposed of in a closed container. Move somewhere safe
  • Weir/block the leak for further disposal if there are significant spills. Avoid anything that might catch fire. 
  • Forbid access into the hazard area by anybody not authorized to be in the area.

How to extinguish fire caused by formalin?

To extinguish fire caused by formalin:

  • Dry chemical, carbon dioxide, water, conventional foam, and alcohol-resistant foam are some options for dealing with little flames.
  • Large fires should be extinguished using a fine water spray or regular foam.
  • If it is safe to do so, remove containers from the location of the fire.
  • Do not use a pressured water stream, which may agitate the spill area further.
  • Dispose of the spill as soon as possible.
  • Use an appropriate fire extinguisher.
  • Avoid inhaling or exhaling fumes from burning things.
  • Stand at a lower place and against the wind.


In this blog post, we have answered the question, “Is formalin flammable?”. We have also discussed what formalin is, the flash point, reactivity, and guidance of storing formalin, then how to extinguish fire caused by formalin.

If you have more questions about formalin and flammability, please comment down below.

Frequently Asked Questions (FAQs): Is formalin flammable?

Is formalin harmful to health?

Inhalation, skin contact, or swallowing might result in skin blisters, burning mucous membranes, eye and respiratory tract irritation (potentially life-threatening), lacrimation, and an increased risk of cancer-causing allergic reactions (in humans).

What are the possible short-term hazards of formalin exposure?

It can induce irritation of the nose and throat, trouble breathing, burning in the nose and throat, and coughing when inhaled at concentrations of 0.1 to 5.0 ppm, 10 to 20 ppm, or 25 – 5 ppm, respectively. 

The additional symptoms include sneezing, trouble breathing, a sore throat, headaches, and dysphagia.

It’s lethal in extremely high doses, so exercise extreme caution. Asthmatic bronchitis, edema of the larynx, severe bronchitis, and urticaria have been recorded in people exposed to formalin.

Pain, white discoloration, hardness, numbness, and degree burns are possible side effects of vapors or solutions in contact with skin. 

It is common for people who have previously been exposed to allergens to develop eczema, vesicular responses, and other skin problems. There have also been reports of urticaria. Rabbits get a fatal dosage of 270 mg/kg.

0.05 – 3.0 ppm may cause eye irritation with redness, itching, discomfort, watering, impaired vision, and significant lacrimation if it comes into contact with the eyes. 

Lacrimation, chronic eye damage, and even blindness can result from exposure to concentrations of 4 to 20 ppm.

As a result of formalin ingestion in gaseous form, mouth, throat, and stomach burning, as well as trouble breathing, nausea, and vomiting (possible blood), severe stomach pain and headaches can occur. 

Also, fainting and coma are possible if the gaseous form of formalin is inhaled. Alterations in the liver, heart, and brain can lead to degeneration, spleen, pancreas, and central nervous system problems, and renal disorders such as acidosis and albuminuria.

What are the possible long-term hazards of formalin exposure?

Long-term inhalation

Chronic exposure can lead to: 

  • headaches 
  • rhinitis 
  • nausea 
  • sleepiness 
  • respiratory distress 
  • renal impairment
  • pulmonary sensitization
  • renal impairment and dysfunction. 
  • Sleep difficulties
  • irritability 
  • balance issues and memory loss. 
  • Female infertility and menstrual irregularities. 

Long-term contact with skin

Second-degree burns, numbness, itching, nail irritation, crusting, and sensitization are possible side effects of repeated or prolonged contact. 

Dermatitis can begin with breakouts in a specific region, spread to other body parts years later, or arise suddenly. As with the skin, severe liver damage in mice was seen following the trial.

Concentration and length of exposure are critical factors in whether or not eye contact has harmful effects. 

It is possible to get conjunctivitis or comparable symptoms after prolonged or repeated exposure to formalin.

If Consumed

Vomiting and dizziness might occur after consuming tiny doses of formalin regularly. There have been reports of sensitization responses. 

Men who drank milk contaminated with formalin for 15 days reported pain in the stomach and headaches. In addition, four males complained of itchy chest and thighs, a burning feeling in the neck, and a drop in body temperature.


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