`` It would be almost like a gas explosion . '' Authorities say a house holds a second homemade explosive , PETN . PETN happens to be the target of new U.S. Army body scans and pat downs . The 8 or 9 pounds of HMTD found is equivalent to a ` ` large '' car bomb , FBI estimates . Bomb technicians must be careful ; the slightest movement could trigger an explosion .
Authorities say a house holds a second homemade explosive , PETN . PETN happens to be the target of new U.S. Army body scans and pat downs . The 8 or 9 pounds of HMTD found is equivalent to a ` ` large '' car bomb , FBI estimates . Bomb technicians must be careful ; the slightest movement could trigger an explosion .