Actually radon was there all the time, even before Naval Research Institute. I grew up myself in this area, and spent in vicinity of the palace more time, than most of you all combine. I release this post not to alarm you about harm, because some of you leave in similar condition:

but raise the question, about Romanov family and servants health possibility, if radon effected anyhow some illnesses, they blamed on tuberculosis everything, but I think some possibility could be long cancer, direct result of the exposure to radon.