The explosives were carried in a soft plastic container - possibly a condom - though much of the packaging was destroyed in the fire, the official said.
The FBI is questioning the suspect, identified as 23-year-old Nigerian Umar Farouk Abdulmutallab, who claimed to be acting on orders from al Qaeda to blow up the airliner, officials said.
A high-ranking law enforcement official told CBS News that the suspect apparently used a syringe to inject a chemical into the powder, which was located near his groin. It is a technique and it's possible that this incident was a test of whether the materials could pass screening and how effective they might be at causing damage, the source said.
According to Encyclopedia Brittanica, PETN is a highly explosive, colorless organic compound, and is related to nitroglycerin. Introduced as an explosive after World War I, PETN is "valued for its shattering force and efficiency ... and is the least stable of the common military explosives but retains its properties in storage for longer periods than nitroglycerin or cellulose nitrate (nitrocellulose) does."
PETN is also used in heart medication as a stimulant.
More Coverage from CBSNews.com:
Official: U.S. Knew of Suspect for 2 Years
U.S. Bolsters Security after Bomb Attack
Report: Father Warned of Bomb Suspect Son
Official: Explosive PETN Used in Attack
Jasper Schuringa ID'd as Flight 253 Hero
Failed Attack Signals New Threat?
Safety in the Air
Fight 253 Terror Scare
Obama Monitors 'Terror' Attempt
The attack began with a pop and a puff of smoke - sending passengers scrambling to subdue the suspect.
Travelers said they smelled smoke, saw a glow, and heard what sounded like firecrackers. At least one person climbed over others and jumped on the man, who officials say was trying to ignite an explosive device.
"It sounded like a firecracker in a pillowcase," said Peter Smith, a passenger from the Netherlands. "First there was a pop, and then (there) was smoke."
The passenger who pounced on the suspect was later , a director from Amsterdam. In extinguishing the explosive device, Schuringa told CNN he suffered minor burns to his hands.
Afterward, the suspect was taken to a front-row seat with his pants cut off and his legs burned. Authorities told CBS News he suffered third-degree burns.
The White House said it believed it was an attempted act of terrorism and stricter security measures were quickly imposed on airline travel. Dutch anti-terrorism authorities said the U.S. has asked all airlines to take extra precautions on flights worldwide that are bound for the United States.
The incident was reminiscent of Richard Reid, who tried to destroy a trans-Atlantic flight in 2001 with explosives hidden in his shoes, but was subdued by other passengers.