Tasmith,
Benzene exposure is usually at the top of the list of suspected causes of bone marrow failure diseases, including MDS, AA and leukemia. You can find quite a bit of info on it by searching online. Here is just one article I found:
http://news.bbc.co.uk/2/hi/health/4065349.stm
It may be hard to prove a cause, but if you know you had long-term exposure to it it certainly seems like a red flag. Are you planning on taking any legal action? Otherwise, knowing the cause doesn't really change much, including the prognosis.