Before we cause alarm, we should discuss what it means for insulation to be toxic to humans. Most common forms of insulation work well because they are lightweight and trap pockets of air throughout the material. Unfortunately, those same features can make the material dangerous.

Here we will discuss how insulation materials can be toxic, and rank them from most toxic to least. We will differentiate between materials that are safe to handle, but toxic when ignited, and those that require personal protective equipment to safely work with normally.

How Is Insulation Toxic?

To be clear, most common forms of home insulation are safe to own, provided they were installed correctly. Most of the danger occurs when the materials are being installed, burn, or are poorly maintained.

Trapped air, not the material itself, is actually what provides most of the thermal barrier between ourselves and outside temperatures. Some form bubbles, some are built up in layers, and others are blown into attic spaces using motorized tools.

Unfortunately, these processes and the materials used in them can be toxic to humans to some degree, in some circumstances. Generally, these insulation materials are irritants to the eyes, skin, and respiratory system in their normal form. However, some emit dangerous fumes, known as volatile organic compounds (VOCs), if they catch fire and burn.

Today we are focusing on insulation that is toxic both to handle, may emit toxic fumes, or both. 

Here’s a list of the most common forms of insulation sorted from most toxic to least toxic:

1.  Asbestos

Up until the mid-1970s asbestos was used as residential insulation. Because asbestos was extremely heat resistant it became a common way to insulate around chimneys, boilers, and other sources of heat. 

Of course, now we know how toxic asbestos is and the variety of health problems it can cause. Asbestos has been found responsible for cancer and respiratory problems, primarily through prolonged exposure.

Asbestos is no longer sold to consumers or included in everyday materials. However, if your home is more than 50 years old it may have asbestos floor and roof tiles, or asbestos insulation. If you suspect asbestos is in your home, contact a local asbestos removal company as soon as possible.

2. Styrofoam

Styrofoam is a form of plastic that is lightweight, and holds its shape well. Styrofoam insulation is very effective at establishing R value, and can be highly controlled as needed. 

Handling styrofoam requires the use of minimum safety gear because the material produces little dust, does not irritate the skin, and is very lightweight.

However, styrofoam can burn, or be melted with solvent, and produce several harmful fumes, known as volatile organic compounds, or VOCs. Carbon monoxide is also produced when styrofoam burns, which can be fatal to humans after even a small exposure.

3. Spray Foam: Closed and Open Cell

Spray foam is created when two chemicals are combined to start a chemical reaction. The result is a durable foam that traps air inside itself as it dries. This makes it ideal for insulating, because the spray is also sticky and will adhere to nearly anything.

Those same benefits can also be toxic to humans. The chemical reaction disburses volatile organic compounds, or VOCs. You can think of VOCs as fumes, which many of us have accidentally inhaled and experienced.

Because spray foam has strong adhesion properties it will bond to skin immediately. Acetone is used to remove spray foam from skin and clothes, but acetone itself also emits VOCs. VOCs can cause respiratory problems, headaches, and nausea, especially in children.

4. Fiberglass: Loose Fill and Batts

Fiberglass is an effective insulation material because it traps air pockets in between the very light strands of glass. 

However, the lightweight nature of fiberglass also means it becomes airborne very easily, and can be breathed into the lungs. Fiberglass will also irritate the skin, so gloves, eye protection, and long sleeves are recommended.

Some forms of fiberglass insulation also may contain formaldehyde, which is toxic and flammable at room temperature. Formaldehyde is used as a binding agent in some forms of insulation, and can cause cancer and respiratory problems over a long exposure.

5. Cellulose: Loose Fill and Batts

Cellulose insulation is made from paper by products, so the material causes less skin irritation than fiberglass. However, the material can become airborne, irritating the lungs and eyes.

Cellulose is often treated with chemicals as well to slow the spread of flame and reduce mold growth. These chemicals can be toxic to those sensitive to them, so skin protection is very important.

Be advised that formaldehyde is also a component of paper production. Although cellulose is generally considered formaldehyde free, it could contain traces of the chemical.

6. Foam Board

Foam board insulation is often made from closed cell spray foam that has been sandwiched between two thin sheets of aluminum. Foam board insulation can emit airborne particles when cut, so most pros use a sharp blade instead of a saw. These particles can be irritating to the lungs and can accumulate.

7. Stone Wool

Stone wool, also known as mineral wool, is likely the safest insulation material to work with. Stone wool creates no VOCs, but it can be irritating to the skin, eyes, and lungs. Stone wool will not burn either, so it will not emit harmful gasses under intense heat.

8. Foil

Aluminum foil has a complicated history as an insulation material. From the 1940’s through the 1960’s aluminum foil was used as wall insulation. The idea was that the aluminum surface would reflect heat from the home back into the room instead of allowing it to escape through the wall.

Fortunately the idea was abandoned in favor of the materials we use today. Today we use aluminum foil more efficiently by installing it under roof materials. 

Known as a radiant barrier, or reflective insulation, foil is placed between the roof sheathing and the roof material, such as shingles. The foil reflects much of the UV energy received from the sun back into the environment instead of letting the home absorb it.

9. Denim

Denim and other cotton products are commonly recycled in insulation blankets, batts, and loose fill. Denim insulation is sometimes treated with chemicals to resist mold growth and heat. Denim insulation is a green option, as much of the material is made from recycled jeans.

10. Hemp

Hemp is a very hardy plant with several famous cousins, including marijuana. Hemp is grown and harvested for hundreds of uses, including insulation. Hemp is a natural fiber, making it another green option with little toxicity.

However, some believe hemp cultivation contributes to greenhouse gasses, so hemp may be toxic, just in a less direct way. 

11. Sheep’s Wool

Sheep’s wool is actually an old version of insulation that is making a comeback. Today, sheep’s wool is available in loose fill and pre-formed batts. Especially popular in countries like Ireland, sheep’s wool insulation is easy to work with, doesn’t make you itch, and is very resistant to heat.

You should consider most common forms of insulation toxic to some degree, and wear the correct personal protective equipment (PPE) for the job. However, some less common forms of insulation, like recycled denim and sheep’s wool, are considered more safe to work with, and are typically less harmful.

Most pros wear protective clothing, eye and skin protection, and a respirator when installing insulation. Repeated exposure can accumulate and lead to health issues later in life. 

Most toxins used in insulation will irritate or even burn exposed skin, so protection is critical to preventing injury. Some forms of insulation can contain small percentages of toxic chemicals, like formaldehyde, while others contain fire retardant chemicals and moldicides. Using an appropriate respirator can help the installer prevent exposure.

How Do I Protect Myself From Insulation?

The common forms of insulation we use today are mostly harmful to the lungs, eyes, and skin. As such, it is important to wear personal protective equipment any time you are working around insulation.

Eye Protection 

Depending on which type of insulation you’re working with, you will need some, or all, face protection. Those working with insulation are among the groups that report the most eye injuries.

Skin Protection 

As mentioned earlier, most forms of insulation are caustic to the skin. Depending on your sensitivity you may want to wear a full body suit, or at least long sleeves and gloves. Fiberglass has a nasty habit of becoming lodged in the skin and breaking off, making removal nearly impossible.

Respiratory Protection

Perhaps the most dangerous toxicity insulation creates involves lung damage. Asbestos was by far the worst offender of any insulation material. However, fiberglass, cellulose, spray foam, and stone wool can create dangerous airborne particles.

What are Some Less Toxic Insulation Alternatives?

As long as proper safety precautions are taken, all common forms of insulation are safe for use in a residential home. These products have all been tested exhaustively for resistance to flame and the limited use of toxic chemicals.

The important part is to follow the directions provided by the manufacturer. Each material will list the recommended procedures and safety gear, so following the list closely will reduce the chance of personal injury.

Here’s a few practical tips to consider if you’re concerned about the toxicity of insulation materials:

  • Use fasteners instead of glues and adhesives. Foam board and styrofoam are commonly installed using some form of adhesive. These adhesives can emit VOCs of their own. Use screws, nails, or staples to help reduce the use of adhesives, and the chemicals used to clean the tools.
  • Use natural wood products, like cork. Cork is a soft, spongy wood and offered in various thicknesses. Cork can be installed with staples or button cap nails to avoid using adhesives.

Cork will burn, but does not emit particles more harmful than regular wood. Cork can absorb moisture, so it must remain dry or mold can begin to grow.

  • Sheep’s wool is another good natural product used as insulation. Sheep’s wool is actually wool, and can be spun into either loose fill form or formed into a batt. Sheep’s wool will not emit toxic fumes, but it will burn just like other hair.
  • Some homeowners use hemp insulation for its green nature and effective R value. Hemp is a plant, which is harvested and used for all sorts of rope and fabric. Hemp insulation does not produce harmful fumes during installation, or if it ignites.

Which Insulation Should I Choose?

Which insulation you choose for your home should represent a balance of cost, effectiveness, and safety. As mentioned earlier, common forms of insulation are safe to use, as long as they are installed as directed.

Wearing the appropriate PPE is the key to installing any insulation safely, so make sure you observe any manufacturer’s recommendations. Generally, wear a respirator, gloves and other skin protection, and eye protection to stay as safe as possible.

If you would normally DIY an insulation project but would like some help this time, the experts at Phoenix Insulation Pros can help. Phoenix Insulation Pros invests in the tools, training, and skills insulating requires.

If you would like a free, no obligation estimate to install your insulation for you, just click here and make an appointment. These insulation experts can not only help you choose the best insulation for your home, but they’ll expertly install it too.


Evan has decades of experience as a project manager for large-scale commercial renovation home-building projects throughout the US. Currently, Evan runs a successful construction management company in Virginia.

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