I'm currently working as a PCM analyst looking at samples to identify asbestos. There is a lot out there still, we are busy every week. (technically PCM doesn't identify asbestos, just the number of fibers during abatement, PLM will identify asbestos but that takes a lot longer to process).
Interesting, I had some vermiculite removed recently and got a response from the ZAI trust that the samples had fibers but they couldn't say specifically that it was asbestos. I assumed that was a legal distinction, it didn't occur to me that it might be from different test methods.
Yeah, for a PCM test we only count 100 fields, and identify the number of fiber end points (upto 2) which with math can give an approx number of fibers/cc2 - helps determine approx how much potential can be in the air (this is usually done during abatement - when it's being cleaned up).
A PLM analyst will use multiple methods to determine if the sample has asbestos, and takes a much longer time.
There are even more expensive tests that can be performed but I'm not so familiar with those.
