A worker measuring levels of radiation in the contamination area between a new confinement structure and the old concrete sarcophagus, visible in the background, that covers the damaged reactor No. 4. All workers use a personal dosimeter to measure and control exposure to radiation and an alarm sounds if safe levels are exceeded. Staff work for two weeks within the contaminated zone and two weeks outside of the zone. Hundreds of tons of radioactive uranium and graphite are still boiling away beneath the sarcophagus, leaking into the ground water and into the air from the decaying building. Although the sarcophagus was built in a rapid six months it came with a heavy, and as yet unknown, long-term toll on the health of those involved in building it. The new structure will have taken nine years to erect but without any workers suffering from radiation related illnesses.