The US Centers for Disease Control and Prevention recommends avoiding Gulf Coast regions affected by the oil spill due to the presence of the toxic substance as well as related activities such as oil burning that are releasing harmful airborne contaminants like methane, benzene and lethal hydrogen sulfide gas, among others.

http://www.digitaljournal.com/article/294098
http://www.salem-news.com/articles/june302010/oil-lifespans.php
http://www.mobiletribune.com/profiles/blogs/0702-is-oil-spill-releasing
http://rt.com/Top_News/2010-07-01/health-concerns-rise-gulf.html