A 2008 study by Metatech found that the time required to obtain a replacement for any one of the 370 or so largest transformers in the United States was 3 years. In a solar superstorm that affects vulnerable areas of the entire world, delivery times could easily be much longer. The United States, which for many years had no capability to manufacture those transformers (and which is just now regaining that capability), will be at the end of a very long waiting line. Since such a expansion of transformer manufacturing capability requires a lot of electrical power, the capability cannot be developed after an electromagnetic catastrophe. The capability has to be developed before there is an actual critical need. In the past five years, two United States companies have begun the process of expanding into the large transformer business, but it will take a considerable length of time before a reasonable number of spare transformers can be manufactured.
Radon is a naturally occurring radioactive gas resulting from the decay of uranium-238, which concentrates in enclosed spaces such as buildings and underground mines, particularly in early uranium mines where it sometimes became a significant hazard before the problem was understood and controlled by increased ventilation. Radon has decay products that are short-lived alpha emitters and deposit on surfaces in the respiratory tract during the passage of breathing air. At high radon levels, this can cause an increased risk of lung cancer, particularly for smokers. (Smoking itself has a very much greater lung cancer effect than radon.) People everywhere are typically exposed to around mSv/yr, and often up to 3 mSv/yr, due to radon (mainly from inhalation in their homes) without apparent ill-effect d . Where deemed necessary, radon levels in buildings and mines can be controlled by ventilation, and measures can be taken in new constructions to prevent radon from entering buildings.