[Mike Irwin]

In a very tony section of Washington, DC, near American University it's a different problem...

They don't find explosives, they find chemical munitions and laboratory equipment, some of it still lethal after nearly 100 years, when they dig for things like swimming pools.

Where American University is now was once a US Army chemical weapons research and development lab when that section of the city, well, was still farm and forest.

After WW II the Army closed the lab down, and much of the equipment, including loaded shells, raw materials, lab retorts, and lots of other goodies, were thrown into pits or natural ravines and covered over. Lots of fun stuff like phosgene, mustard, Lewisite, etc.

Now it's the location of multi million dollar homes. Apparently when the homes were being built none of this stuff was found (or so is claimed). It was later when people started digging in their back yards to put in swimming pools and stuff like that that it started turning up.

Every couple of years the Army Corps of Engineers descends on the area and starts digging frantically after someone uncovers something, and every time they say "We've finally got it all!"

Yeah.