The Official Account
NIST wrote as if no one — including members of the Fire Department of New York — gave evidence of explosions in the Twin Towers. 
The Best Evidence
Over 100 of the roughly 500 members of the FDNY who were at the site that day reported  what they described as explosions in the Twin Towers. Similar reports  were given by journalists, police officers, and WTC employees.
References for Twin Towers Point 3
- NIST, “Answers to Frequently Asked Questions,” August 30, 2006 (8/6/2006), Question 2.
- Graeme MacQueen, “118 Witnesses: The Firefighters’ Testimony to Explosions in the Twin Towers,” Journal of 9/11 Studies, Vol. 2, August 2006, 47-106.
- Reports by journalists, police officers, WTC employees are summarized here: David Ray Griffin, “Explosive Testimony: Revelations about the Twin Towers in the 9/11 Oral Histories,” 911Truth.org, January 18, 2006.