Why does some vermiculite contain asbestos?
Vermiculite is a silicate mineral that is mined from the ground. The presence of asbestos in vermiculite is dependent on the presence of asbestos in the same rock formation that the vermiculite is mined from (Asbestos is a set of 6 silicate minerals and is also mined from the ground). Therefore, when they were mining vermiculite in the past, they were unknowingly mining asbestos with it making asbestos a contaminant in the vermiculite. In the past this was considered a benefit as asbestos is resistant to heat, electricity, and chemicals making it a fantastic insulation product. Unfortunately our bodies are unable to break asbestos down and it can cause extensive damage to the respiratory system. Non-asbestos containing vermiculite is still mined and can be found at hardware stores. It is commonly used for gardening.
How do I know if the vermiculite in my attic contains asbestos?
If you have vermiculite insulation in your attic space, always take the precautionary principle and assume that it is contaminated with asbestos until proven otherwise. In order to determine if vermiculite contains asbestos it must be sampled and analyzed by a lab. At Hazpro we have two AHERA Building Inspectors on staff able to complete this sampling for you. Normally vermiculite contains around 1% tremolite or actinolite asbestos. It is not recommended that you take a sample of the vermiculite unless you are a trained professional who is aware of the proper sampling technique and have the appropriate PPE.
If the vermiculite in your attic is the second type of vermiculite that is large white flakes then there is a good chance that it does not contain asbestos. In order to prove that it is not asbestos containing, WorksafeBC requires that we take three large samples and have the samples analyzed using a technique that is not offered on Vancouver Island. Therefore the samples are sent away and analyzed using extremely expensive microscopes and techniques. This method is more costly but is worth it if the vermiculite is determined not to contain asbestos.
I have Asbestos-containing Vermiculite. Now what?
The presence of asbestos in vermiculite only becomes an issue if you plan on doing a renovation that will impact the space and cause the vermiculite to be disturbed. For example, when ripping down a ceiling, roof work, electrical work, plumbing work, demolition, etc. Asbestos-containing vermiculite can also be an issue when buying or selling a home (Please see Are you buying a home with asbestos in it?).If the vermiculite needs to be disturbed then it must be removed under High-Risk Asbestos Abatement work procedures which are laid out by WorkSafeBC prior to any disturbances occurring. There are two ways of removing the vermiculite from the attic. The first is the conventional method and the second is the Hazpro method. I will describe the conventional method first.
The Conventional Method of removing vermiculite is an extensive process. The basic steps are simplified below.
Step 1: A three-stage decontamination unit (3 plastic rooms with a shower in the middle) is set up at the attic access. This containment must include a full portable shower as it is required that all workers who enter the workspace shower before exiting the workspace.
Step 2: The entire attic must be made airtight by sealing all openings. The space is then put under negative pressure using a HEPA filtered negative air unit that ensures that all air flows into the work zone and out through the HEPA filter.
Step 3: Air sampling must be completed on a daily basis to ensure that there are no asbestos fibers leaving the containment and to ensure that the workers are adequately protected by their respirators.
Step 4: The vermiculite waste and all other contaminated insulation is shoveled and bagged in one layer of 6 mil poly. The bags are then rinsed in the shower and then bagged in a second layer of asbestos labeled 6 mil poly and transferred out to the waste bin. This process continues until as much vermiculite as possible is removed.
Step 5: All surfaces in the attic must be vacuumed with a small HEPA filter vacuum to remove the bits and pieces that may not have been bagged.
Step 6: An encapsulating glue is sprayed on all surfaces to ensure that any fibers that may not be visible to the human eye are secured to a surface and unable to become airborne.
Step 7: Finally, a third party consultant complete air clearance sampling to determine that the space is safe for reentry. Once air clearance is granted then the containment can be removed.
This process normally takes 4-6 business days depending on the size of the attic, amount of insulation, and other factors.
The Hazpro Method: At Hazpro, we want to make this process as pain free as possible so we have built Victoria’s first and only High Powered Vermiculite Vacuum truck. This is a self-contained vacuum truck that allows us to simply vacuum the vermiculite straight from the attic into the vacuum where it is then bagged. This means that we are not required to put a portable shower in your home. Less space is required at the attic entrance and we also do not need to transport all of the waste through your home as it is vacuumed directly to the vacuum. This leap in technology also reduces the time and manpower required to remove vermiculite, which in turn allows us to pass savings on to you. This method has many advantages but Step 2,3,5,6 and 7 described above must still occur even when the vacuum is used.