The D.O.E came out to clean up my warehouse of U-235 (?) back in 1994. The place was used during WW II to machine billets of uranium. They would machine the billets and let the pieces fall onto the dirt ground. The DOE sub-contractors, Bechtel, came in and saw cut the concrete reinforced floor and removed the dirt below the extra thick concrete. The workers dug eight feet deep in some sections approximately 30 x 50 yards. Shipped the dirt and old concrete out to a place in Tennessee and re-filled with clean dirt. My Uncles won the bid to lay the concrete floor and finish the outside block work. The Government most likely knew that the U-235 would kill the unprotected workers who probably worked with the uranium as if was common steel. The floor was extra thick (according to the sub-contractor) to shield the radiation from future people and it took them four months to clean it up. They would seal a section of the warehouse, approximately 50 feet x 50 feet, with plastic from floor to sealing and remove the contaminated dirt through a zippered door. They would work 6 PM to 6 AM so not to impede our operations. The workers did not use respirators, but had to keep the dirt wet so that the U-235 would not become airborne. I wonder if any of them have cancer after 24 years. One guy knew my Grandfather, who died in 1980, and told me that this was one of the easier jobs as they did not need to wear full protection. He told me that they go into nuclear reactors to work and they are only allowed to stay in a few minutes out of the hour at a time. I choose to keep my distance for those few months from the front warehouse.