Posted by: Li Ling Young | September 4, 2012

Vermiculite Contains Asbestos

When we bought our house we knew that it had vermiculite in the attic, and we knew that we wanted it out.  The seller was willing to share some of the cost of removing the vermiculite and gave us $5000 off the cost of the house price.  The vermiculite removal cost about $7500.

The main reason we removed the vermiculite is that we intended to do aggressive air sealing and insulating in the attic.  In a ranch the attic is a large part of the envelope of the building.  Fortunately, that means about 25% of the envelope can be easily accessed and upgraded without having to disturb the finished surfaces on the inside or outside of the house…  Unless there’s poisonous stuff all over the attic floor.  On our way toward energy Valhalla we need to be able to make an awesome thermal envelope at the ceiling.  The vermiculite had to go.

I like to think of vermiculite as rock popcorn.  It’s not a bad insulation, though it has a low insulating value per inch.  It can withstand very high temperatures, which makes it good for insulating around chimneys.  However, the source for 70% of the US’s vermiculite, the mine at Libby, Montana, also contains a vein of asbestos.  It’s prudent to assume that any vermiculite installed before 1990, when the Libby mine was shut down, contains asbestos.  In fact, testing for asbestos in vermiculite is an unreliable way to determine whether your vermiculite is contaminated.  Just assume any old vermiculite has asbestos in it and treat it accordingly.

So, what’s so bad about asbestos?  Inhaled asbestos can cause several kinds of lung cancer.  Asbestos fibers are very tiny.  Neither a dust mask, nor your nose hairs will catch them, and they lodge deep in lung tissue.  Many years after exposure to vermiculite those fibers can cause a tumor to grow.  I appreciate my lungs.  And I like to think I would never ask a worker to do something personally hazardous (even if they’re not so fond of their lungs as I am of mine).  No vermiculite if work is going to go forward in the attic.

We hired Alderson Environmental to remove the attic insulation.  They are licensed by the state to remove and dispose of asbestos.  I asked them what their process would be, how they make sure vermiculite dust doesn’t get into the house and how they dispose of the vermiculite. They do a lot of this work because a lot of homes in this area have vermiculite in them.  As part of the contract Alderson disclaims not all of the vermiculite will be removed.  Some vermiculite may remain, for instance in electrical fixtures.

We were lucky that Alderson could schedule us for immediately after the closing, so that by the time we moved in the vermiculite removal would be done.  I stopped in while they were doing the work.

The environmental company built this containment area in our garage. The workers enter the work area through this containment area and are decontaminated here..

The workers shower after having been in the work area. These showers are in the containment area so they don’t track hazardous material outside the work area.

Here’s their containment zone with showers for the workers.  Pretty impressive.  Air quality testing inside the house is done continuously during the work.  After the work was done someone from a state lab came and did air quality testing in the attic.  The jobsite failed air quality testing so they had to leave a giant fan in the attic over the weekend and retest on Monday, when the test showed everything OK.

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s


%d bloggers like this: