The Asbestos Survey has become a precondition of almost every construction scheme. And almost always comes up positive unless you're building on a greenfield site. You see, Asbestos is ubiquitous; it's contained in the hard plastic that old toilet seats are made out of, in lino floor tiles and even as flash pads inside electrical switches. Dig a trial pit on any London brownfield site and you'll find Asbestos - even if it's in an old Bakelite doorknob.
But it's all religiously removed by blokes in full respirator suits and double-bagged for disposal in special landfill sites. And people wonder why construction is so expensive ...
Asbestosis and Mesothelioma usually occur after high intensity and/or long-term exposure to asbestos (particularly in those individuals working on the production or end-use of products containing asbestos). There is much scientific literature on the subject, including An Expert System for the Evaluation of Historical Asbestos Exposure as Diagnostic Criterion in Asbestos related Diseases by Burdorf and Swuste (Erasmus) published by the British Occupational Hygiene Society (Full text HERE).
I reproduce the decision tree for Mesothelioma below;
The disease is only attributable to Asbestos where exposure exceeds daily working exposure in air containing over 1 fibre per 2 cubic centimeters for more than six months.
If you're going to comment, please do so on the basis of attributable scientific evidence, not scary folk-tales and anecdotal evidence.