Maps, compasses, astrolabes, and calipers are among the early tools used by ocean navigators. In the modern era, these tools have been largely replaced by electronic and technological equivalents. Despite these early beginnings, it would take many centuries before global navigation at sea became possible.
Harmful Effects of Radon. 1  Radon is the second leading cause of lung cancer (diagram to the right) and a serious public health concern. 2  The primary adverse health effect associated with chronic exposure to radon is lung cancer (typically bronchogenic): -squamous cell carcinoma.
16% of lung cancers deaths in Canada are attributable to radon exposure. The only known health effect of radon is an increased chance of developing lung cancer. Radon is the second leading cause of lung cancer after smoking. Because it is radioactive, radon decays.