Nuclear Waste Disposal Area One was the first waste dumping area on the Moon. It was closed in 1994; it was later identified as Navigation Beacon Delta, a distinctive landmark for traffic on the route to NDA2. It was built without synthocrete radiation covers; instead the silos are covered with large mounds of lunar regolith capped on orange monitoring domes. In-between the domes are towers, formerly used to provide artificial gravity (the same design as those surrounding Moonbase Alpha) and now used as flashing beacons.
The area was continually monitored by automatic systems; in early September 1999, a sharp rise in heat and a 20-fold increase in magnetic field was detected, although radiation levels remained normal. On September 11th, Area One burnt itself out in a magnetic sub surface fire storm.