The theft was discovered Sunday night by local authorities.
ATF agents are investigating the large theft from Cherry Enginering, a company owned by Chris Cherry, for decades the senior explosives scientist at Sandia National Laboratories in New Mexico.
Also, 2,500 detonators were missing from a storage explosive container, or magazine, in the name of Cherry Engineering.
The theft is one of the largest reported cases from a facility in the United States in the last decade ending 2004. During that time, a total of about 1,000 pounds was reported stolen from government facilities in 14 reported incidents. It is unknown whether there is any connection to terrorism.
A special agent at ATF said the incident was unusual because such high-powered material was targeted.
One hundred and fifty pounds of the plastic explosive compound C-4 and 250 pounds of undetectable "sheet explosives" — a DuPont flexible explosive material that can be hidden in books and letters — were stolen in the burglary, which also included the theft of blasting caps.
Burglars used a torch bar to break into the explosives containers and remove the material.
The missing material could potentially make numerous bombs.