Vermiculite is a mineral that has been used to insulate homes for decades. However, the vast majority of vermiculite insulation in North America came from a mine that also contained asbestos, which can cause lung disease and cancer.
If your home contains vermiculite insulation, you need to know how to avoid disturbing it and how to protect yourself when you enter your attic. In some cases, removal is necessary, and you can even be reimbursed for it.
The EPA recommends treating all vermiculite as contaminated. It is best to leave vermiculite alone, ideally sealed within walls or contained in an unused attic. Vermiculite should only be handled by professionals.
Vermiculite Insulation Risk: Asbestos Exposure
The Libby Mine in Montana, active starting in the 1920s, was contaminated with a natural deposit of asbestos.
Before the mine closed in 1990, it supplied 80% of the vermiculite sold in the United States under the name Zonolite insulation for decades.
Not all vermiculite insulation contains asbestos, even if it was installed before 1990, because not all vermiculite was mined at Libby. When new vermiculite insulation is installed today, suppliers must provide proof of asbestos testing.
You cannot tell by looking at it whether vermiculite insulation contains asbestos.
The U.S. Environmental Protection Agency (EPA) advises people to assume that vermiculite is contaminated and take precautions. Most states, including New York, list vermiculite as a suspect miscellaneous asbestos-containing material.
If contaminated vermiculite insulation is disturbed, asbestos fibers can become airborne and get inhaled.
The negative health effects of asbestos are caused by inhalation and mainly relate to lung conditions. Asbestosis—scarred lung tissue that makes breathing difficult—occurs in people who had high and prolonged exposure through their jobs.
Asbestos can also cause lung cancer, mesothelioma, and larynx cancer. Furthermore, research increasingly suggests that asbestos is linked to colorectal and ovarian cancers.
Apart from the potential contamination with asbestos, vermiculite by itself has not been found to pose any threats to health.
Official Recommendation: Leave It Alone
Avoid disturbing the vermiculite. Officials leading asbestos research, policy on asbestos handling, and the EPA all say to leave vermiculite alone if it is not an active threat.
While it might seem like common sense to get rid of the potential threat, asbestos is most dangerous when fibers are disturbed and become airborne.
Interacting with the vermiculite in any way—removing it, blowing new insulation over it, or simply going into your attic—can cause asbestos fibers to be released into the air.
While we will discuss options for professional removal, this should only be done in particular circumstances, for example if a remodeling or maintenance project will disturb the insulation.
Vermiculite should not be removed for the sake of removing it.
Most importantly, never attempt to remove, adjust, or touch vermiculite insulation by yourself.
Precautions to Take
Get the Vermiculite Sealed In
Sealing can mean one of two things.
On the low-tech end, vermiculite can be covered with plywood boards or Tyvek to create a barrier. This is recommended for “inactive” attics that will not usually be entered.
Additionally, seal the ceiling of rooms below the attic. Dust from vermiculite insulation can fall through cracks in the ceiling, particularly around light fixtures and fans. Apply caulking around the attic hatch or make sure that the attic door seals.
For insulation contained within finished walls as opposed to unfinished attics, caulking is a good first step. The EPA does not recommend opening up walls to check for vermiculite. Caulk around window and door frames, baseboards, and outlets if you suspect that you have vermiculite.
Asbestos-contaminated vermiculite is much less dangerous when contained within a wall cavity than when left open to the air in an attic.
Sealing can also mean asbestos encapsulation—spraying an approved protective coating like AsbestoSafe, which should be done by a professional. A spray sealant, used in conjunction with another barrier, is recommended for “active” attics where objects will be stored or contractors will be working.
Cover With New Insulation
Professionals have differing opinions on the question of whether you should add new insulation over the top of vermiculite, or have it professionally removed before re-insulating.
Some asbestos remediation companies recommend installing certain forms of insulation like fiberglass batts (not blown-in fiberglass), as long as a sealant is sprayed on the vermiculite.
However, some insulation companies argue that simply adding new insulation, regardless of the type, runs the risk of disturbing asbestos fibers.
Another issue to consider is that once new insulation comes into contact with vermiculite, it is considered asbestos-contaminated. If you ever need to reinsulate again, it will be more expensive to remove both materials.
Never cover vermiculite with blown-in insulation, as the blowing process will disturb asbestos fibers.
Stay out of the Area
Each trip to your attic increases the risk of inhaling asbestos fibers and releasing more fibers. Limit the number of trips you make to the attic and limit the length of those trips.
Staying out of the area usually means not using the attic whatsoever. Do not store boxes, furniture, or any items in the attic.
The EPA specifically mentions that children should not enter the area.
While no level of asbestos exposure is considered safe, the risks of disease depend on the level, duration, and frequency of exposure.
Strategies like sealing in the vermiculite address the level of exposure; staying out of the area addresses the duration and frequency of exposure.
Wear PPE if You Have to Enter The Area
Whenever you must enter your attic, wear personal protective equipment (PPE).
Common dust masks and surgical masks, including even N95 masks, are not enough to protect you from asbestos fibers. Effective PPE in this situation means wearing a respirator mask, as required by OSHA in the context of workplace asbestos exposure.
Other best practices for entering an asbestos-contaminated attic include:
- Stay on the floored part of the attic or walk on boards to avoid kicking up dust.
- If you must move or remove boxes (as you should not store anything in the attic), move them very gently.
- Leave the attic as soon as possible.
- Change clothes and shoes so that you do not track dust into your primary living space.
Monitor the State of the Vermiculite
It is important to make sure that vermiculite is not degrading or shifting. Dust and fragments can fall through cracks into other areas of your home. If you notice changes to the appearance of the vermiculite, that could be a sign that something is wrong.
However, when monitoring vermiculite, be careful to follow the procedure outlined above. Wear a respirator and avoid making extra trips to the attic. Try to check on the insulation when you have to enter the area for another reason.
You should not open a wall to check on vermiculite insulation. Similarly, lifting up boards to look at the vermiculite means disturbing the potential asbestos fibers and should be avoided.
If you cannot see your vermiculite insulation without uncovering or unencapsulating it, the costs of disturbing it generally outweigh the benefits of monitoring it.
If you are concerned that something has changed, consider hiring a home inspector to test for asbestos or purchasing an asbestos testing kit. Testing the air for asbestos is more accurate and noninvasive than testing a physical vermiculite sample.
Because asbestos fibers are dangerous when inhaled, you might think that ventilation would reduce exposure. However, increasing ventilation in your home is not something that most asbestos experts recommend.
Vents or open windows that blow air around the attic could disturb the vermiculite. If you or a contractor has to spend time in the attic, wearing a respirator to protect against asbestos fibers is much more effective than increasing airflow.
Increasing ventilation in areas other than the attic to reduce asbestos exposure is not an official recommendation.
If you are concerned that asbestos is getting into your main living spaces, the problem cannot be addressed simply through ventilation. In that case, contact an accredited asbestos inspector.
Remodelling Must Be Done by a Professional
You may need to have vermiculite removed or have contractors follow special procedures if you plan to do work on your attic or remove walls, for example:
- Electrical rewiring
- Installing bathroom vents or certain types of ceiling lights in rooms below the attic
- Renovations due to water or fire damage
- Planned renovations
- Bat or rodent infestation
- Air sealing and re-insulating the attic for energy efficiency
Home improvement projects that require access to the attic or the removal or opening of walls must be done by a professional. It is vital to notify plumbers, electricians, and other contractors that you have, or suspect you have, vermiculite insulation.
Sometimes contractors will be able to complete their work while following extra safety procedures. However, some projects, like air sealing and deep renovations, require the professional removal of vermiculite.
Professionally removing vermiculite is allowed and necessary in such cases, even though the EPA recommends that you avoid removing vermiculite in general.
Get It Tested Before Removal
If you eventually end up needing or wanting to remove vermiculite, it must be done by an accredited professional trained in asbestos handling. Be aware that common methods of removal like vacuuming are dangerous when applied to vermiculite.
Testing vermiculite for asbestos can lead to false negatives (when a physical sample of the mineral tests negative but the air tests positive). Because of uncertainty around testing, the EPA recommends treating all vermiculite as contaminated even if it tests negative.
Testing a vermiculite sample for asbestos can’t tell you whether or not you need to remove vermiculite, or even how much you are being exposed.
However, a different form of vermiculite testing can be incredibly useful for another reason.
You can submit a sample (collected by yourself, by a home inspector, or by a Certified Asbestos Professional) to Zonolite Attic Insulation (ZAI), who will perform a constituent analysis test to determine if your vermiculite came from their Libby mine.
If the test shows that your vermiculite is Zonolite, the ZAI Trust may have to reimburse you for up to 55% of the cost of removing and replacing the insulation.