You might not like my answer at all, and I don't want to get all analytical on you....but I used to have the fear of lead poisoning. To be honest, the fear is not what is important, rather what is important is what kind of pathology the fear points to.
For me, the fear of lead was the fear of losing my intelligence. That being said, i had a whole spectrum of fears related to that problem and they didn't go away until i started to confront that issue head on....i.e. to not be afraid of losing/not placing as much value on my intelligence.
The truth is, even if you overcome you phobia of mercury and asbestos, that fear will only transform into some other phobia until you address the underlying issue.
This post is a bit old but I was searching for people like me. I can’t even read some of the replies because they set me off. But just want you to know that I know what you are going through and you are not alone. It feels very lonely to be like this because no one takes your fears seriously. I don’t worry about myself being contaminated, but a loved one. It’s very hard. And don’t take me being afraid of it as a reason to justify you being afraid. We are totally exaggerating the risk and we are fine. I’m sure you know this too, but it doesn’t stop us from being afraid.