How does asbestos cause lung cancer?

asbestos is a naturally occuring substance that is basically strands of crystals that can embed themselves in your lung tissue.  on type, called crocidolite, is the worst kind of asbestos because the crystals have barbs on them that burrow into your lung tissue and causes cancer.  Crocidolite is mined in Africa and is banned in the US by the EPA.  there is a misconception that all asbestos is bad for you, but white asbestos does not cause cancer because the crystals are too big and rounded to embed themselves.  anyway, i hope this helped...

The carcinogenic nature of asbestos (chrysotile) has been related to the shape of the particles more than their composition. In other words, the substance itself is not carcinogenic - the shape is!

Chrysotile produces very thin fibers that can be many times longer than they are wide. When these become embedded in the lungs, larger particles can be coughed out but smaller particles need to be carried out by a type of white blood cell called a macrophage. Unfortunately, small asbestos fibers tend to be so long relative to their width that they tend to be actually longer than the macrophages. When the macrophages try to engulf them, the cells puncture and the macrophages die before they can do their job.

The EPA has targeted asbestos fibers over 8 micrometers in length as being the bad actors in causing mesothelioma (asbestos-related cancer), and claims that particles shorter than about 4 micrometers are not harmful (although this point is still being argued). Theoretically, the macrophages can successfully engulf shorter particles and get rid of them.

So why the cancer? There have been various theories about the mechanism. One theory is that the constant release of biochemical "distress signals" given off by the dying macrophages are the actual cause of the cancer. Another theory is that the asbestos particles have active surface sites for the generation of free radicals from oxygen, and that the free radicals are capable of reacting with and damaging the surrounding cells.

It's an interesting story. The link below has everything that you need (it is basically a list of resource papers and articles) although you will have to do some work to sift through the material.

The summary I wrote here is just from memory. When I was in university many moons ago this was one of the hot research topics in our department, so I got to see a lot of presentations on the subject although it was not an area in which I was personally working.

Good luck on the project