The fires at Ground Zero (GZ) did not diminish despite the use of millions of gallons of water, a chemical fire suppressant Pyrocool, and rain fall. The pulverized concrete blanketed the area and also failed to suppress the red hot fires from the debris piles. An
article by Dr. Steven Jones, Kevin Ryan, and James Gourley, argues that, "such fires are better explained given the presence of chemical energetic materials, which provide their own fuel and oxidant and are not deterred by water, dust, or chemical suppressants." Energetic chemical materials are evidenced, says the article, by: (1) Photographs and witness testimony evidencing molten metal and explosions accompanied by white dust clouds; (2) Extremely high temperatures in the fires at the WTC; (3) Unusual spikes in volatile organic chemical (VOC) emissions, suggesting abrupt, violent fires on specific dates; (4) Unusual species in the environmental monitoring data, also corresponding to specific dates.
The presence of 1,3 Diphenylpropane (DPP) and other materials and characteristics have yet to be explained by the government and EPA.
For those new to 9/11 studies, or if you're interested in current 9/11 research, a good place to start is
Scholars for 9/11 Truth and Justice. This group of academics, scholars, and professionals create peer reviewed research easily accessible to the public.