we begin this morning with too close for comfort. this morning the nation s premiere nuclear laboratory is under siege. fire crews in new mexico are scrambling to drive back a wildfire that has now reached within just 50 feet of the los alamos national lab. nbc s kurt gregory reports. reporter: a fierce wildfire continues to grow in los alamos. very close to the los alamos national laboratory. firefighters are working day and night to clear brush and extinguish spot fires near the sprawling nuclear research facility. we have not lost any structures at the laboratory or in a town site and we don t plan on losing any structures. reporter: the secret of los alamos laboratory is made up of nearly 2,000 buildings at 4,000 sites. home to the largest supply of nuclear weapons. our facilities and nuclear materials are protected and safe. reporter: another concern the possible release of radioactive and harmful materials. thousands of 55-gallon drums containing plutonium-c