Is Formaldehyde Flammable? What You Need To Know Now

Suppose you worked in a hospital, used fertilizers for your farm, or are a photographer who washes films. If that were the case, you would have used formaldehyde several times. Even household items like paints, cosmetics, and glues contain formaldehyde.

But you need to ask yourself: Is formaldehyde flammable? In this post, we will break down the flammability of formaldehyde and provide tips for safe handling.

Is Formaldehyde Flammable

Is Formaldehyde Flammable?

The answer is yes. Formaldehyde is flammable. It is a flammable gas that can easily ignite at room temperature, depending on its concentration. In addition, the liquid form of formaldehyde is also highly flammable, and formaldehyde vapor, when mixed with air, is explosive.

What Is Formaldehyde's Flash Point?

Flash point is the minimum temperature necessary for a substance, especially liquids, to burn in the presence of an ignition source. It measures the degree to which substances easily catch fire. For instance, formaldehyde’s flash point sits at around 255°F - 300°F.

Formaldehyde has a boiling point of -2.2°F, which means it's volatile and evaporates at room temperature. This vaporized form of formaldehyde forms an explosive mixture when combined with air.

How Flammable Is Formaldehyde?

Formaldehyde is highly flammable, and its flammability increases with the increase in formaldehyde or methanol concentration. This increased flammability is due to a reduced flash point caused by the increased concentration.

These flame retardants often form a protective layer around the material's surface that delays ignition. However, it's pure in its liquid form and quite easily ignitable, with a flash point between 255°F - 300°F. Although the National Fire Protection Association(NFPA) describes flammable substances as ones possessing flash points below 100°F, formaldehyde is still considered quite flammable.

What Is Formaldehyde?

Formaldehyde is an organic compound that occurs naturally from the amino acid serine. It is a colorless, reactive, and poisonous gas under normal conditions but can be converted into a colorless aqueous solution. This gas is flammable at room temperature and is readily soluble in water.

It is also made industrially in labs from a compound called methanol. The aqueous solution is denser than water and has a strong and sharp smell. In its vaporized form, it's denser than air. It is irritating to the nose and is toxic when swallowed. It's also called methanal or formalin.

Why Is Formaldehyde Flammable

Uses Of Formaldehyde

Formaldehyde is used in various industries and for multiple purposes. It is used to make molded casts and insulation. Some formaldehyde polymers are used in making permanent adhesives for plywood. It is also a compound used to make paints and explosives.

The aqueous form of formaldehyde is also called formalin and is used as a disinfectant. In healthcare, it is used as an additive in the production of vaccines to inactivate pathogens and toxins. It is also used as an embalming agent and tissue fixative to preserve tissue cells.

Formaldehyde is also an active ingredient in the process of drug testing. It helps to identify specific compounds in drugs, especially alkaloids, quickly. It is also used in photography for washing films.

Is Formaldehyde Corrosive?

Formaldehyde is corrosive. However, its corrosivity isn't across all metals. For example, the liquid form isn't corrosive to stainless steel and aluminum alloys, but it’s corrosive to carbon steel. It is also corrosive to the skin, eyes, and respiratory tract.

How To Put Out A Fire From Formaldehyde 

Formaldehyde is a flammable gas, and it is possible to start or cause a fire. To handle a fire from formaldehyde, you must understand that it is a Class B or C fire, which means it involves a flammable gas or liquid.

You should only use water in Class C fires to reduce the temperature of heated surfaces, and it should be applied even after the fire is out. Isolate the fire area, ensuring you evacuate people from the site of the fire.

Contact the fire support team immediately, especially if you're not trained to extinguish a fire caused by flammable gases. The suitable fire extinguishers for a formaldehyde fire are Class C extinguishers. There are six classes of fires with their corresponding extinguishers. These are:

  • Class A (solid substance) – water, foam, wet chemical, and dry chemical
  • Class B (flammable liquids) – water mist, dry chemical powder, foam, and carbon dioxide
  • Class C (flammable gases) – dry chemical powder and water mist
  • Class D (combustible metals) – carbon dioxide and dry chemical powder
  • Class E (electrical fires) – carbon dioxide and dry chemical powder
  • Class F (cooking oils and fats) – wet chemical

A fire caused by formaldehyde is classified under Class B or C, depending on the state of the compound (gas or liquid). Therefore, you should use the corresponding extinguishers. As most gas fires are left to burn out after the gas supply is shut off, the firefighters will determine the most suitable method to fight the fire.

How Flammable Is Formaldehyde

Safety Precautions For Handling Formaldehyde 

Take these steps to ensure your safety, as well as anyone else working with formaldehyde.

Store Your Formaldehyde Properly 

Formaldehyde should be stored in containers not exposed to fires, direct sunlight, static electricity, or sparks. In addition, you should keep it in tightly sealed, appropriately labeled containers.

You should also keep it away from other chemicals, especially oxidizing agents like bleach and other chlorine substances. It should also be kept away from children and pets to prevent accidental ingestion. 

Ensure You Use Personal Protective Equipment When Handling

Using personal protective equipment like face shields and safety goggles is best to prevent eye contact with formaldehyde vapor when handling formaldehyde. This vapor irritates the cornea, and long-term exposure could cause permanent damage.

Full-face masks that protect the respiratory tract from vapor inhalation should be used. Also, you should wear heavyweight PVC or neoprene gloves to prevent direct contact with the skin, as it can cause burns. 

Ensure Proper Disposal 

Refrain from pouring formaldehyde or waste products into the drains and sinks or tossing them in an incinerator. Formaldehyde should be considered a chemical hazardous waste. Instead, it should be dropped off or picked up by Environmental Health and Safety (EHS).

Final Thoughts

The short answer to the question: Is formaldehyde flammable? Yes, it is. It will readily ignite when heated. It's very reactive and can be explosive. It's best to store it in well-ventilated, cool areas away from heat and electrical sparks.

Avoid inhaling the vapor or fumes it releases, as it's hazardous to your health. And remember, always keep your extinguishers handy.