What Was So Toxic at the Pentagon?

I knew it was bad at Ground Zero, but hadn't heard of this happening at the Pentagon site:

Special Agent Melissa Morrow died on Thursday.

Kansas City, MO - FBI Special Agent Melissa Morrow, 48, died on Thursday from a 9/11 related illness.

On September 11, 2001, agent Morrow was assigned to the Evidence Response Team at the FBI's Washington Field Office, according to Kansas City Star. ODMP reports that she spent 10 weeks collecting evidence in contaminated conditions at the site of the terrorist attack on the Pentagon.

In 2013 she also responded to a six-alarm fire at a warehouse containing contaminated evidence from the Pentagon, according to Kansas City Star.

Agent Morrow later developed brain cancer as a result of those conditions, which ultimately killed her. Her death is classified as a line of duty death.

Agent Morrow served in the FBI at the Kansas City field office at the time of her passing.

Former FBI agent Ali Soufan tweeted:

Ali H. Soufan ‏ Verified account @Ali_H_Soufan Mar 23

FBI SA Melissa Morrow passed away on Thursday. She was a 9/11 first responder and was exposed to toxins at the Pentagon. Melissa is the 11th FBI Agent lost due to such exposures. Remember the many who continue to suffer from the health impacts of 9/11.

11 FBI agents died from 9/11 exposures at the Pentagon? Or altogether? Would make more sense if most were at GZ...