Specifically what are the risks to my health and at what levels of exposure?
Public Lab is an open community which collaboratively develops accessible, open source, Do-It-Yourself technologies for investigating local environmental health and justice issues.
As an open source community, we believe in open licensing of content so that other members of the community can leverage your work legally -- with attribution, of course. By joining the Public Lab site, you agree to release the content you post here under a Creative Commons Attribution Sharealike license, and the hardware designs you post under the CERN Open Hardware License 1.1 (full text). This has the added benefit that others must share their improvements in turn with you.
This is a complex question. Oil pollution can have a variety of impacts on a person’s health, or the health of an ecosystem. In addition to birds and other wildlife getting covered by an oil slick which can result in hypothermia or suffocation, oil is comprised of several toxic compounds that can have severe consequences. Polycyclic aromatic hydrocarbons (PAHs) in oils can impair reproduction, physiological and neurological development in marine organisms, and some PAHs are likely to be carcinogenic in humans (e.g. Pelletier et al, 1995, Samanta et al, 2002). Other volatile components of oil may induce headaches, nausea, and respiratory difficulty during even short exposures (e.g. Solomon and Janssen, 2010). For more information about studies investigation human health effects of exposure to oil, please see this ATSDR reference and this NIOSH reference, both hosted by the national Centers for Disease Control.