The research was funded by NIOSH (National Institute for Occupational Safety and Health) and the CDC (The Center for Disease Control and Prevention). The study of 800 participants was conducted from January 2011 through September 2013. The dynamics of the study included how long each participant was exposed to 9/11 particulate matter and how close in proximity they were to Ground Zero. The study also showed evidence that inhaling these toxic particles also increased risk of PTSD. Those responders in the study who had PTSD also had biological characteristics that point to increased risk of cardiovascular disease. It was found that those WTC responders with PTSD had substantially higher levels of hsCRP (high sensitivity C-reactive protein), a key indicator of increased cardiovascular disease risk.